Graphene/Ag–Ag2S based hybrid nanostructure for methylene blue degradation

In this study, novel 2D/1D graphene/silver-silver sulfide (Ag–Ag₂S) hybrid nanocomposites were successfully synthesized and characterized using X-ray Diffraction (XRD), Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). The structural–optical properties and dye-photodegradation performance of Ag nanowires (NWs), Ag–Ag₂S core–shell NWs, and a 2D/1D graphene/Ag–Ag₂S hybrid nanocatalyst were examined. SEM confirms uniform, non-agglomerated Ag NWs and a layered graphene morphology; after sulfidation, Ag₂S (and incidental Ag₂O) forms on Ag NW surfaces, while Ag–Ag₂S NWs are randomly distributed across graphene sheets. XRD results confirm the presence of crystalline phases corresponding to Ag, Ag₂S, and silver oxide (Ag₂O), indicating successful hybridization and partial oxidation during synthesis. UV–Vis spectra show the two Ag localized surface plasmon resonances (LSPR) (∼350/380 nm) collapsing into a broadened band upon Ag₂S shelling, consistent with higher dielectric loss and interfacial damping; graphene/Ag–Ag₂S is dominated by a π–π* transition near 200–250 nm. Tauc analysis yields, E.g., ≈ 2.9 eV (Ag NWs), and after hybridization, approximately 2.5 eV (Ag₂S), 3.8 eV (Ag), and 4.6 eV (Ag₂O); the composite (graphene/Ag–Ag₂S) exhibits two optical gaps (∼3.28 and 4.72 eV), reflecting its multiphase nature and graphene-induced states. Methylene blue (MB) degradation follows pseudo-first-order kinetics with the strongest linearity for graphene/Ag–Ag₂S (R² ≈ 0.89–0.92). At pH 3, the hybrid achieves the highest removal efficiency (89.55% at 5 h) and the largest rate constant (k_obs = 0.5349 h⁻¹). The synergy arises from assisted carrier generation in Ag, heterojunction-driven separation in Ag–Ag₂S, and rapid electron transport/π–π adsorption on graphene, which together maximize radical formation and suppress recombination under acidic conditions.

1 Introduction

The global shortage of clean water continues to grow, prompting the search for science- and technology-based solutions. In this context, hybrid photocatalytic materials have become especially promising. Industrial dye effluents significantly contribute to water pollution, with the textile industry identified as the main source. Literature indicates that approximately 54% of wastewater contains dyes, emphasizing the scale of the challenge and the need for effective decolorization methods (Katheresan et al., 2018; Kaushal et al., 2021). Among common model pollutants, methylene blue (MB)—a phenothiazine dye—remains widely used for performance testing because of its persistence and known risks to environmental and human health (Khan et al., 2022). Photocatalytic dye removal occurs through light-excited charge carriers in a semiconductor. Photoexcitation generates e⁻/h⁺ pairs; their interfacial reactions produce reactive oxygen species (·OH, O₂·^-) that break down organic compounds into CO₂ and H₂O (König, 2013; Mohamadpour and Amani, 2024; Muhd Julkapli et al., 2014). Therefore, practical efficiency depends on broad or visible-light absorption, rapid charge separation and transport, minimized recombination, high surface area, and photostability. To meet these needs, recent studies have engineered plasmonic/semiconductor and carbon-hybrid architectures—such as Ag–Ag₂S heterostructures and graphene-based composites—that improve visible-light harvesting and carrier lifetimes, resulting in higher MB degradation rates compared to their single-component versions (Chen et al., 2020; Hu et al., 2016).

Single-phase photocatalysts and adsorbents have long served as benchmarks for MB removal. Ag nanoparticles (NPs) can quickly decolorize MB under light, with recent reports showing approximately 90%–95% removal within minutes and pseudo-first-order rate constants around 10⁻¹ min⁻¹. This is attributed to strong LSPR-assisted charge generation and electron transfer to MB (sodium dodecyl sulfate (SDS)-capped Ag NPs achieved 92.5% in 12 min, k ≈ 0.263 min⁻¹) (Almarashi et al., 2024). As a single phase, Ag₂S (α-Ag₂S) functions as a narrow-gap (≈1 eV) visible-light photocatalyst. Studies report efficient MB degradation under sunlight and visible light via reactive oxygen species (ROS) formation, with activity adjustable by particle size and surface states (e.g., Ag₂S and Ni/Ag₂S under visible light, cellulose-fiber/Ag₂S films reaching nearly 100% MB removal in about 2 h of sunlight) (Kharlamova and Kramberger, 2022). Graphene-based materials (GO/rGO) are excellent as single-phase adsorbents for MB due to π–π interactions and electrostatic attraction; rapid uptake and high capacities are widely reported (such as quick GO adsorption, and metal-free rGO acting as an adsorbent and photocatalyst under natural light) (Siong et al., 2019). Collectively, these benchmarks clarify intrinsic roles: LSPR-enabled reduction and photocatalysis for Ag, band-gap-driven visible-light response for Ag₂S, and high-surface-area adsorption with charge shuttling for graphene-based materials.

Ag nanomaterials with one-dimensional shapes (nanowires, nanorods) show excellent optical, electrical, thermal, and mechanical responses, mainly because of their high aspect ratios and strong LSPR effects (Yang et al., 2023). In particular, LSPR in Ag nanostructures depends heavily on size and shape: smaller particles shift the resonance to blue and increase sensitivity to the surrounding refractive index, while different shapes (spheres, triangles, rods, wires) allow precise tuning of optical responses for sensing and electrocatalysis (Ditlbacher et al., 2005; Wiley et al., 2006; Yang et al., 2023). Silver sulfide (Ag₂S) is a chalcogenide semiconductor mainly found as monoclinic acanthite (α-Ag₂S), which is semiconducting at room temperature, and it transforms into body-centered-cubic argentite (β-Ag₂S) at higher temperatures, showing superionic Ag⁺ transport; nanoscale studies directly observe the α↔β transitions and confirm superionic behavior above around 450 K (Gusev and Sadovniov, 2017; Sadovnikov and Gerasimov, 2019; Simonnin et al., 2020). Electric-field–induced resistive switching in Ag/Ag₂S junctions further demonstrates the mobility of Ag species and how conductivity is affected by phase or state changes (Billy et al., 2017; Gubicza et al., 2016; Gusev and Sadovniov, 2017). Ag₂S has a narrow direct band gap near 1.0 eV, allowing strong absorption in the near-infrared region (Trukhanov et al., 2007; Xiang et al., 2008), making it useful for IR-active optoelectronics and photodetectors (Mubarokah et al., 2023; Wang F. et al., 2022; Zamiri et al., 2015). Its mixed ionic and electronic transport, along with high Ag⁺ conductivity, supports applications in solid-state ionics, sensors, and memory devices (Boussaida and Masrour, 2023; Shahjamali et al., 2016; Simonnin et al., 2020). When size is confined, the band gap widens; for instance, Ag₂S nanoparticles (NPs) show, E.g., increasing from about 0.88 eV at roughly 500 nm to around 1.21 eV at approximately 60 nm, which aligns with quantum-size effects (Darvishi and Seyed-Yazdi, 2016; Sadovnikov et al., 2016). In the literature, Ag–Ag₂S composites have also been combined with CdS to enhance visible-light activity toward dyes like MB. However, since Cd compounds are toxic and carcinogenic, these systems are not considered eco-friendly (Eswari et al., 2022; Gahramanli et al., 2024a; Gahramanli et al., 2024b; Peana et al., 2022).

Graphene, a carbon-based material considered relatively “green” and highly compatible with aqueous processing, combines extremely high electrical and thermal conductivities with excellent mechanical properties (Xin et al., 2015). Its in-plane tensile strength (∼130 GPa) and Young’s modulus (∼1 TPa) define practical limits for supporting and conductive frameworks in hybrid catalysts and membranes (Lee et al., 2008; Scarpa et al., 2009). Graphene is also chemically stable in many environments and processing methods, enabling strong device integration (Zhao et al., 2017; Zhou and Bongiorno, 2013). Due to its single-atom thickness and mass-free Dirac-fermion electronic structure, a single layer absorbs only about 2.3% of visible light but can maintain ultrahigh carrier mobility (up to ∼200,000 cm² V⁻¹ s⁻¹ in clean suspended devices). This makes it useful for transparent electrodes and fast charge transfer in photocatalytic hybrids (Bolotin et al., 2008; Castro Neto et al., 2009; Nair et al., 2008; Zhen and Zhu, 2018).

Building on these baselines, hybrid nanostructures consistently outperform single phases by combining light harvesting, interfacial charge separation, and adsorption or dispersion. Ag–Ag₂S heterostructures use Schottky or ohmic junctions to suppress e⁻/h⁺ recombination and extend the response into the near-infrared. Ag–Ag₂S nanoplates showed significantly faster MB degradation than either component alone under visible light (Chen et al., 2020). Adding graphene (rGO or graphene) to Ag₂S provides a conductive network and additional adsorption sites, resulting in better visible light MB degradation than pure Ag₂S (Hu et al., 2016). Ternary systems further enhance these synergies: Ag/Ag₂S/rGO composites and related Ag₂S–oxide–graphene junctions demonstrate higher rates and better cycling stability due to efficient interfacial charge routing and dye preconcentration (e.g., Ag/Ag₂S/rGO; Ag₂S-sensitized NiO–ZnO) (Shafi et al., 2019). Beyond all-Ag based materials, AgNWs integrated into metal–organic frameworks (MOFs) like ZIF-8@AgNWs and various rGO-oxide hybrids also show accelerated MB removal under visible light and sunlight, underscoring the broad applicability of plasmonic–semiconductor–carbon coupling (Gahramanli et al., 2025; Negash et al., 2023).

Collectively, these advances justify exploring new Ag/Ag₂S/graphene-type hybrids as efficient, photostable catalysts for dye removal under real-world conditions, while recognizing that testing on actual wastewater samples (beyond model MB solutions) is an essential next step for practical application (Katheresan et al., 2018; Khan et al., 2022; Mohamadpour and Amani, 2024; Muhd Julkapli et al., 2014; Pradyasti et al., 2020). The main goal of this work is to build on our previous publication by employing a novel graphene-based hybrid nanocomposite combined with Ag–Ag₂S nanostructures for MB degradation (Gahramanli et al., 2025). The study aims to leverage graphene’s superior electron mobility, high surface area, and excellent conductivity to enable rapid charge separation and transfer during photocatalytic reactions. By integrating these benefits with the visible-light activity and semiconducting properties of Ag–Ag₂S, the nanocomposite is expected to achieve increased photocatalytic performance. The research emphasizes developing an environmentally friendly, low-cost, and highly effective photocatalyst for environmental uses such as wastewater treatment and breaking down organic pollutants. The combined use of graphene and Ag–Ag₂S is examined to improve stability, reusability, and light-harvesting capabilities under sustainable conditions.

2 Experimental part

2.1 Synthesis of Ag NWs

Ag NWs were synthesized using the polyol method (Alsalme et al., 2024; Gahramanli et al., 2024a). First, silicone oil was added to the reaction vessel and heated. Next, 5 mL of ethylene glycol (EG) was poured into a glass vessel and then into the silicone oil. The temperature was expected to rise to 160 °C. A mixture of 0.063 g of AgNO3 and 2 mL of, EG was stirred on a magnetic stirrer for 10 min. Then, 10 mL of CuBr2 and 15 mL of NaCl were added dropwise to the ethylene glycol over 10 min. After that, 1.5 mL of the AgNO3 mixture and 1.5 mL of PVP were slowly added dropwise to the solution over 15–20 min. The reaction was carried out for 3 h. The final solution was washed with cold water, cooled, and then 9–10 mL of acetone was added, followed by centrifugation.

2.2 Synthesis of Ag–Ag₂S NWs

To synthesize Ag–Ag2S nanostructures, first, 1.33 g of Na2S is dissolved in 35 mL of distilled water to prepare a 200% solution. Then, 5 mL of the Na2S solution and 5 mL of the Ag NWs solution are taken, and both are added dropwise to the reaction vessel. The mixture is stirred for 1 h to ensure good dispersion, and the final solution is centrifuged in the same manner.

2.3 Synthesis of graphene nanoplates

Graphene was synthesized in a liquid medium using a microwave oven. This method stands out for its simplicity and environmental friendliness compared to other synthesis techniques. In this process, graphene layers are separated by microwave irradiation of partially exfoliated graphite in isopropyl alcohol. First, 100 mg of exfoliated graphite is dispersed in 50 mL of isopropyl alcohol. The mixture is then subjected to ultrasonic waves for 1 h. Afterward, it is filtered through filter paper, and the alcohol is absorbed with an absorbent. The mixture is then stored in a heater for 24 h to evaporate. During this time, the high evaporation capacity of isopropyl alcohol creates internal pressure between the graphite layers, weakening Van der Waals forces and causing the graphene layers to separate. This physicochemical process results in the formation of high-quality graphene layers. The obtained graphene is then dried and ground into powder.

2.4 Fabrication methodology of 2D/1D-graphene/Ag–Ag₂S

To prepare the composite graphene/Ag–Ag2S nanocomposites, first, 0.008 g of Na₂S was dissolved in 10 mL of distilled water. In parallel, 0.011 g of pre-dried Ag NWs was mixed in 10 mL of acetone, and 0.0292 g of graphene was mixed in 10 mL of isopropyl alcohol for 30 min to obtain homogeneous solutions. Then, Na₂S solution was added dropwise to the Ag solution using a magnetic stirrer over 20–30 min. Next, 3.33 mL of each prepared solution was taken and mixed on a magnetic stirrer for 2 h. After mixing, the samples were centrifuged and washed three times with ethanol to purify them. The resulting product was dried at room temperature and powdered.

2.5 Photocatalysis process of MB dye by using graphene/Ag–Ag₂S nanocatalyst

The degradation process of synthesized Ag, Ag2S NWs, and the composite material graphene/Ag–Ag2S was carried out under white light for 60, 120, 180, 240, and 300 min in different environments of MB dye using the formed graphene/Ag–Ag2S hybrid nanocatalysts in a neutral environment (pH = 6). To evaluate the degradation efficiency, graphene/Ag–Ag2S hybrid nanocatalysts were added to the prepared MB dye at a concentration of 10 ppm, and the mixed solution was exposed to white light for various durations.

To assess the degradation efficiency in an alkaline environment (pH = 10), which may have been affected by various additives (organic compounds), diluted 1M NaOH was added to the prepared 10 ppm MB dye. It was determined that the pH of the environment remained at 10. The same procedure was used to evaluate the degradation efficiency of these materials in an alkaline medium. To create an acidic medium (pH = 3), diluted 1M HCl was added to 10 ppm of MB dye. Experiments were conducted similarly, and the degradation efficiency was measured. To determine the degradation efficiency in all three environments, samples were examined at hourly intervals using UV-Vis spectroscopy. An amount of 0.01 g of each sample was used as a nanocatalyst, and the degradation of 10 mL of MB dye was studied in different pH environments. Based on the absorption spectrum observed each hour, the degradation efficiency was calculated using Equation 1 (Wang et al., 2009).

$\frac{{\mathrm{C}}_0-C}{{\mathrm{C}}_0}*100\%=\frac{{\mathrm{A}}_0-A}{{\mathrm{C}}_0}(1)$

where C0, C, A0, and A are the concentrations and absorptions of the dye at (0) and (t) minutes under the reaction conditions, respectively. The rate constant for the photocatalytic decomposition of MB dye by hybrid nanocatalysts was analyzed using the Langmuir–Hinshelwood (LH) kinetic model and shown as Equation 2 (Sadovnikov et al., 2016).

$\mathit{ln}\frac{{\mathrm{C}}_0}{C}=K_{obs}t(2)$

In the Formula 1/($K_{obs}$ t) concerning time, the derivative and intercept correspond to (C₀)/Kc and 1/(Kc K_lh) = $K_{obs}$ t, respectively. K_c is the rate constant of the surface reaction (mg L^-1min^-1) (Khezrianjoo and Revanasiddappa, 2012). The predicted degradation mechanism of MB by the graphene/Ag–Ag₂S hybrid nanocatalyst is shown in Figure 1.

Figure 1

Figure 1. Degradation mechanism of MB by the graphene/Ag–Ag₂S hybrid nanocatalyst.

At Ag–Ag₂S (and Ag₂S–X, if a third semiconductor or carbon is present) interfaces, band offsets (or an S/Z-scheme) generate internal fields that separate photogenerated electrons and holes, so more electrons reach O₂ to form ·O₂⁻ and more holes produce ·OH—, both speeding up MB oxidation (Alsalme et al., 2024; Huang et al., 2024). Under visible light, Ag’s LSPR creates strong near-fields and hot electrons that inject into the nearby semiconductor (Ag₂S or CdS, etc.), increasing reaction rates beyond either component alone; this plasmon-assisted separation and transfer are well established (Abouelela et al., 2021; Amirjani et al., 2023; Collado et al., 2018; Tatsuma et al., 2017). Because Ag₂S has a narrow band gap (∼1 eV), combining it with plasmonic Ag and/or a wider-gap partner creates stepwise energy levels (Schottky or Z/S-scheme), allowing efficient use of visible-to-NIR light and offering multiple charge-transport pathways that pure Ag or Ag₂S NWs lack (Liu et al., 2020; Zhang et al., 2019). Hybrid nanostructures expose more varied facets and metal/semiconductor boundaries, lowering overpotentials for surface redox steps and helping activate adsorbates, which accelerates degradation.

Graphene/rGO hybrids with Ag₂S (and/or Ag) enhance π–π adsorption, which pre-concentrates MB on the surface, and provide ultrafast electron highways that reduce recombination and boost steady-state reactive oxygen species (ROS) flux. Graphene-modified Ag₂S demonstrates higher visible-light activity through improved adsorption and electron transport (Hu et al., 2016; Shakoor et al., 2024). Compared to pristine Ag and Ag₂S NWs (Balamurugan and Maruyama, 2005), these plasmonic–semiconductor hybrids (i) amplify visible-light harvesting via Ag LSPR and hot-electron transfer, (ii) create internal electric fields or Z-scheme pathways that significantly reduce e⁻–h⁺ recombination, and (iii) increase the number of interfacial active sites (and, with carbon supports, improve dye adsorption and charge mobility), collectively enhancing ·O₂⁻/·OH flux and speeding up MB mineralization (Liu et al., 2020; Zhang et al., 2019).

2.6 Characterization methods

The structure of Ag, Ag2S, and graphene, both as individual components and as a composite material (graphene/Ag–Ag2S), was characterized using X-ray diffraction spectra (λ = 1.54060 Å with Ni-filtered Cu Kα radiation, Model MiniFlex 600, Rigaku Co. Ltd., Tokyo, Japan). To determine the absorbance spectrum and band gap values, as well as to investigate the degradation of MB dye over time, UV–Vis spectrophotometry (Model Specord 250 PLUS, Analytik Jena AG, Germany) was used. Chemical bonds were analyzed using FTIR spectra obtained from an IR Affinity-1 FTIR spectrometer (Shimadzu, Japan) within a wavenumber range of 400–4000 cm⁻¹. The morphology of the samples was examined with a Field Emission Scanning Electron Microscope (Model JEOL JSM-7600F, JEOL Ltd., Tokyo, Japan).

2.7 Uncertainty propagation of the degradation percentage (%d) of MB

This section summarizes the formulas shown in Equations 3-9, compiles instrument-related uncertainty components for absorbance measurements in the 200–800 nm range (Analytik Jena SPECORD UV–Vis- PLUS series), and demonstrates the propagation of uncertainty to the percent degradation. Absorbance A at a single wavelength λ is considered a measured quantity with a standard uncertainty u(A). The degradation percentage (D%) is defined as Equation 3:

$D\%=\frac{\left(A_0-A_t\right)}{A_0}\times 100=\frac{\left(1-A_t\right)}{A_0}\times 100(3)$

According to Guide to the Expression of Uncertainty in Measurement, the uncertainty propagation for a function F (x, y) is:

${\sigma }^2\left(y\right)={\displaystyle \sum _i}{\left(\frac{\partial F}{\partial x_i}\right)}^2{{\sigma }_{x_i}}^2+2{\displaystyle \sum _{i<j}}\frac{\partial F}{\partial x_i}\frac{\partial F}{\partial x_j}COV\left(x_i{x}_j\right)(4)$

Si ${\sigma }_{A_0}$ y ${\sigma }_{A_t}$ son las desviaciones típicas (incertidumbres estándar) y $COV\left(A_0,A_t\right)$ su covarianza, entonces:

${\sigma }^2\left(D\%\right)={\left(\frac{\partial D\%}{\partial A_0}\right)}^2{{\sigma }_{A_0}}^2+{\left(\frac{\partial D\%}{\partial A_t}\right)}^2{{\sigma }_{A_t}}^2+\frac{\partial D\%}{\partial A_0}\frac{\partial D\%}{\partial A_t}COV\left(A_0,A_t\right)(5)$

Derivadas parciales:

$\frac{\partial D\%}{\partial A_0}=-\frac{100}{A_0},\frac{\partial D\%}{\partial A_t}=100\frac{A_t}{{A_0}^2}(6)$

Entonces:

${\sigma }^2\left(D\%\right)={\left(\frac{100}{A_0}\right)}^2\left[{{\sigma }_{A_t}}^2+{\left(\frac{A_t}{A_0}\right)}^2{{\sigma }_{A_0}}^2-2\frac{A_t}{A_0}COV\left(A_0,A_t\right)\right](7)$

The spectrometer used in the absorbance measurement is SPECORD PLUS (50/200/210/250 PLUS). Wavelength capability covers UV–Vis; the following photometric specifications apply (values from the official technical data sheet):

• Photometric accuracy (VIS, 546 nm, neutral glass filter Hellma F4): ±0.003 A

• Photometric accuracy (UV, potassium dichromate): ±0.010 A (used for UV; not used in the VIS example below)

• Photometric reproducibility (RMS at 546 nm): ≤0.0005 A

• Baseline noise at 500 nm (RMS): ≤0.0001 A

• Long-term stability at 500 nm: ±0.0005 A per hour

• Stray light: ≤0.03 %T at 220–240 nm; as low as ≤ 0.01–0.005 %T near 340 nm

Uncertainty of a single absorbance reading A. For a single absorbance reading A in the VIS, a conservative standard uncertainty can be estimated as Equation 8:

${\sigma }_A=\sqrt{{{\sigma }_{instr}}^2+{{\sigma }_{repeat}}^2+{{\sigma }_{noise}}^2+{{\sigma }_{drift}}^2}(8)$

Where:

${\sigma }_{instr}$ = 0.003 A (VIS photometric accuracy),

${\sigma }_{repeat}$ ≈ 0.0005 A,

${\sigma }_{noise}$ ≈ 0.0001 A, and

${\sigma }_{drift}$ ≈ (0.0005 A/h) × t with t the measurement span in hours.

If measurements of A₀ and At are taken within 10 min (t = 1/6 h), then u_drift ≈0.0005 × (1/6) = 0.000083 A. Hence:

${\sigma }_A=\sqrt{{0.003}^2+{0.0005}^2+{0.0001}^2+{0.000083}^2}\approx 0.0030A(9)$

3 Results and discussions

3.1 Morphological analysis

The synthesized 1D-Ag and Ag₂S NWs, as well as 2D/1D graphene/Ag–Ag₂S nanocomposites, have been examined by SEM in Figure 2.

Figure 2

Figure 2. SEM images of Ag (a), Ag–Ag₂S (b) NWs, and graphene/Ag–Ag₂S (c) composite materials.

As shown in Figure 2a, pure Ag NWs were formed, with spherical small particles visible on them, as evident from the SEM images. After hybridization, Ag2S forms on the surface of the pure Ag NWs, along with Ag2O compounds in the form of crystallites (Gallardo et al., 2012) (Figure 2b). The morphology of the graphene/Ag–Ag2S nanocomposite materials is illustrated in Figure 2c. Both NWs and spherical nanoparticles are visible on the graphene surface in the Ag–Ag2S NWs nanocomposite. Therefore, the successful formation of the graphene/Ag–Ag2S hybrid nanocatalysts is confirmed by both structural and optical properties.

3.2 Structural analysis

X-ray structural analysis was used to determine the composition of composite materials. Figure 3 presents the individual structures of the compounds (Ag, Ag–Ag₂S, graphene) included in the composite material.

Figure 3

Figure 3. X-ray structural analysis of Ag (1), Ag–Ag₂S (2) NWs, and graphene/Ag–Ag₂S (3) composite materials.

As shown in Figure 3, three main diffraction peaks were observed at 2θ values of 38.0°, 44.8°, and 63.7°. These peaks relate to the cubic structure of Ag and match the ICDD 00-001-1167 database, as shown in the literature (Tseng et al., 2021). The peaks are indexed with the Miller indices (111), (200), and (220), respectively. The crystallite size, calculated using the Debye–Scherrer equation for each peak, is approximately 1.94 nm. The structural analysis of the Ag–Ag2S NWs after hybridization is shown in Figure 3. The diffraction pattern indicates that, after hybridization, Ag2S and Ag2O compounds form on the surface of the pure Ag NWs. These phases are labeled with Miller indices (−112) and (121), corresponding to acanthite Ag2S (JCPDS Card No. 14-0072) and cubic Ag2O (JCPDS Card No. 89-3722). The Debye–Scherrer method estimates the crystallite size at around 2.3 nm (Xiong et al., 2016). Since the structure is a 1D core-shell type, with Ag2S NWs forming on the surface of pure Ag NWs, the crystallite sizes increase compared to pure Ag due to the formation of Ag2S. Various sizes of Ag2S can develop on the surface of Ag, which can also affect the, E.g., value of the Ag–Ag2S NWs (Baghirov et al., 2024). Figure 3 presents the XRD analysis of 2D/1D structured graphene/Ag–Ag2S composite materials. The peak at 2θ = 26.4° corresponds to the (002) Miller index and has an interplanar spacing of 3.35 Å. Peaks at 2θ = 44.6° and 54.68° belong to graphene (Wang et al., 2017). Additionally, the peaks at 2θ = 38.07° and 64.36° are diffraction peaks from Ag NWs. No characteristic peaks of Ag2S are observed in the recorded diffraction pattern, likely because the characteristic peaks of Ag2S are weaker compared to those of other components.

3.3 Optical properties

To study the absorption spectra of the samples (Figure 4), each was studied by UV-Vis spectroscopy. The absorption spectrum of Ag (1), Ag–Ag₂S (2) NWs in Figure 4a, and graphene nanoplates (1), and graphene/Ag–Ag₂S (2) composite materials in Figure 4b was studied.

Figure 4

Figure 4. Absorbance spectrum of (a) Ag (1), Ag–Ag₂S (2) NWs, and (b) graphene (1), and graphene/Ag–Ag₂S (2).

The absorption spectrum of the synthesized Ag NWs displays two characteristic peaks at 350 nm and 382 nm (Cirit et al., 2024; Gebeyehu et al., 2017). The peak at 350 nm is due to the out-of-plane quadrupole resonance of the Ag NWs, while the more intense peak at 380 nm results from the out-of-plane dipole resonance (Gao et al., 2005). As shown in the absorbance spectra of Ag–Ag₂S NWs (Figure 4a), the two shoulder-like peaks typical of pure Ag NWs are missing (Zhang et al., 2017). With increasing Ag₂S coverage during hybridization, the wires become thicker and their surfaces more fully coated with Ag₂S. During sulfidation, sulfide ions (S^2-) diffuse inward most efficiently at the surface—where their concentration is highest—and less effectively with depth due to limited penetration. This process reduces the electron concentration near the surface and suppresses SPR.

Consistent with previous reports on Ag NWs (∼350/∼380 nm LSPR) and their sulfidized versions, Ag–Ag₂S NWs no longer show the ∼350 nm shoulder. The Ag₂S shell increases dielectric loss and boosts interfacial non-radiative damping, causing a broadened, merged band instead of two separate Ag modes (Gebeyehu et al., 2017; Jiang et al., 2017; Wang S. et al., 2022). Mechanistically, the Ag₂S shell (i) raises the local refractive index and introduces lossy dielectric damping (higher extinction coefficient), which broadens and weakens the Ag LSPR; (ii) adds surface/Ohmic and interfacial charge transfer pathways that dissipate plasmon energy non-radiatively; and (iii) changes morphology/roughness, disrupting coherent transverse modes. Collectively, these effects suppress the distinct shoulder observed in bare Ag NWs. Reports on Ag@Ag₂S systems show the same replacement of sharp Ag peaks with broadband absorption, and general LSPR theory also predicts peak broadening and attenuation when a metal is coated with a higher-index, absorptive shell (Jiang et al., 2017; Li et al., 2015; Mcoyi et al., 2025; Wang et al., 2012). The frequency of plasmon oscillations depends on the charge carrier concentration, as shown by Equation 10, which relates plasmon oscillations to charge carrier density (Zhu et al., 2015).

${\omega }_p=\sqrt{\frac{N_h{e}^2}{{\epsilon }_0{m}_h}}(10)$

Where e is the electron charge, ε0 is the permittivity of free space, mh is the hole effective mass (approximately 0.8 m0, where m0 is the electron mass), and Nh is the free hole density. Equation 10 shows that plasmon oscillations are influenced by charge carrier concentration. In other words, the frequency of plasmon oscillations varies with concentration. Because there are many free-charge carriers on the metal’s surface, the frequency of plasmon oscillations is also high. When the free charge carriers on the metal’s surface are replaced by a different concentration in the semiconductor, the frequency of plasmon oscillations decreases. The decrease in electron concentration reduces the SPR frequency. As Ag₂S is less conductive than metallic Ag, the formation of Ag₂S causes a decrease in the SPR frequency, shifting the plasmon band toward longer wavelengths—a red shift in the UV–Vis absorption spectrum. After hybridization, a red shift is observed in the absorption peaks (Gahramanli et al., 2024c).

Thus, based on the results obtained from UV-Vis spectroscopy, it can be said that both Ag and Ag–Ag₂S NWs were successfully synthesized. Since oxygen is dissolved in water during hybridization and the reaction is carried out in an atmospheric environment, oxygen is not removed from the reaction environment (it is not carried out in a nitrogen environment), Ag₂O is formed as a result of the oxidation of Ag, which is evident from both XRD and UV-Vis. results.

Figure 4b shows the UV-Vis spectra of graphene. The absorption spectrum of graphene displays a typical absorption curve reported in the literature (Gahramanli et al., 2024c) for graphene nanosheets. According to the literature, weak absorption in the range of 320–680 nm is characteristic of graphene nanosheets. Figure 4b shows the absorption spectra of graphene/Ag–Ag2S nanocomposites. As seen in the spectrum, the main absorption region of the nanocomposites is between 200 and 250 nm. This corresponds to the π–π* electronic transitions of graphene, related to its π-electron system (Uzek, 2024). Such transitions are characteristic of the ultraviolet range, common in aromatic structures, especially in carbon-based materials, and are also observed in graphene oxide or functionalized graphene structures (Dreyer et al., 2010).

Conversely, the Ag and Ag₂S nanostructures in the nanocomposite also influence the spectrum. Ag NWs can absorb in the visible and near-UV regions due to SPR. Typically, the SPR peak for Ag nanostructures is between 350 and 450 nm. However, because of the interaction of Ag–Ag₂S NWs with graphene and the formation of solid solutions or interactions of Ag with Ag₂S, this absorption band shifts to a lower wavelength — 250 nm (blue shift) (Liz-Marzán, 2006). After 250 nm, absorption drops sharply and stays nearly constant for wavelengths above 300 nm. This occurs because the nanocomposite is mainly active in the UV region and absorbs minimally in the visible spectrum.

In Figure 5, Tauc curves are presented to determine the band gap value for Ag (a), Ag₂S (b) NWs, as well as graphene/Ag–Ag₂S (c) composite materials.

Figure 5

Figure 5. Determination of the bandgap value of Ag (a), Ag–Ag₂S NWs (b), and graphene/Ag–Ag₂S hybrid nanocomposite materials (c).

By extrapolating the obtained straight line, the band gap of Ag NWs (Figure 5a) was found to be 2.9 eV. Although pure bulk Ag nanostructures do not have a band gap, Ag nanostructures exhibit a certain band gap due to quantum effects. This is explained by the increase in SPR and size effects, especially for 1D structures (NWs) (Jana et al., 2001). Due to hybridization, the band gap value tripled (Figure 5b). Consequently, after hybridization, Ag₂O was also formed in the composite material. Based on the Tauc plot analysis, the, E.g., values after hybridization were approximately 2.5 eV for Ag₂S, 3.8 eV for Ag NWs, and 4.6 eV for Ag₂O.

Two different straight-line extrapolations of the composite material were obtained from the (αhν)² ∼ hν dependence of graphene/Ag–Ag2S in Figure 5c. Using these lines, two different band gap energies of 3.28 eV and 4.72 eV were determined. This reflects the multiphase and multicomponent nature of the material. The graphene component can create local states that influence optical conductivity and electronic transitions (Eda and Chhowalla, 2010). Therefore, 3.28 eV is linked to low-energy transitions resulting from the interaction between nanoscale Ag₂S and graphene. The other, E.g., value (4.72 eV) is due to changes in plasmon resonance and carrier mobility caused by incorporating graphene into the Ag-based structure, leading to broadening of energy levels. This suggests that the 2D/1D graphene/Ag–Ag2S nanocomposites have potential applications in photocatalysis.

3.4 FTIR analysis

FTIR analysis was performed to determine the chemical bonds between elements in graphene/Ag–Ag₂S composite materials, and the results are shown in Figure 6.

Figure 6

Figure 6. FTIR spectrum of graphene/Ag–Ag₂S nanocomposite materials: 1-Ag NWs; 2-graphene; 3-graphene/Ag–Ag₂S.

Figure 6 shows the FTIR spectrum of the synthesized materials. In Figure 6, the spectrum of pure Ag NWs displays 2200–2000 cm⁻¹ – CO vibrations adsorbed on the Ag surface (Wang et al., 2025), 1660 cm⁻¹ – weak vibrations in PVP are slightly shifted due to the carbonyl group C=O, which coordinates with the silver surface (Kumar et al., 2017). The 1100–1050 cm⁻¹ peak corresponds to C–O stretching, related to PVP and residual, EG. These results indicate that the surface of the Ag NWs is coated with PVP. In Figure 6, the spectrum shows 3400–3200 cm⁻¹ – O–H stretching of adsorbed water, and 1630–1580 cm⁻¹ – weak aromatic C=C skeleton vibrations characteristic of pure graphene (Dreyer et al., 2010). The IR spectrum of graphene/Ag–Ag2S nanocomposites is shown in Figure 6. A broad absorption band around 3552 cm⁻¹, 3476 cm⁻¹, and 3415 cm⁻¹ can be attributed to O–H stretching vibrations (generally within 3300–3600 cm⁻¹), due to adsorbed moisture or hydroxyl groups in the precursor graphite structure (Hadi et al., 2018) (Wang et al., 2025). A notable absorption peak at 1621 cm⁻¹ corresponds to the C=C stretching vibration of the sp²-hybridized carbon atoms in the hexagonal graphene lattice (Ickecan et al., 2017) (Kumar et al., 2017).

A weaker band at 1696 cm⁻¹ is assigned to the C=O stretching vibration, characteristic of PVP chains adsorbed onto the surface of Ag NWs (Shokri Doodeji et al., 2024) (Dreyer et al., 2010). The Ag–S vibrational mode appears as a peak at 537 cm⁻¹, which is also often associated with Ag–O bonds, indicating the presence of both Ag₂S and Ag₂O phases (Pradheesh et al., 2020; Zamiri et al., 2015) (Hadi et al., 2018; Zamiri et al., 2015; Zamiri et al., 2015). Overall, the main FTIR signals are primarily attributed to graphene, reflecting its high surface area and abundance of functional groups. In contrast, signals related to silver compounds (Ag₂S and Ag₂O) are weaker. These FTIR results align with the XRD and SEM analyses, confirming that oxidation took place during the sulfidation process, as shown by the presence of oxygen-containing vibrational modes.

3.5 Photodegradation of MB by graphene/Ag–Ag₂S nanocatalyst: UV–Vis absorbance evolution, degradation efficiency, and kinetic rate analysis

Both the separately prepared Ag NWs and the Ag–Ag2S NWs obtained after hybridization, as well as the composite graphene/Ag–Ag2S hybrid nanocatalysts, were used to perform photocatalysis of MB dye in various environments with pH levels of 3 (acidic), 6 (neutral), and 10 (alkaline) for 60–300 min. To assess degradation efficiencies, absorption spectra were recorded every 60 min using UV-Vis spectroscopy. Figure 7 displays the absorption spectra collected during the photocatalysis process with Ag NWs for neutral (Figure 7a), alkaline (Figure 7b), and acidic (Figure 7c), with Ag–Ag2S NWs for neutral (Figure 7d), alkaline (Figure 7e), and acidic (Figure 7f), and with graphene/Ag–Ag2S nanocomposite materials for neutral (Figure 7g), alkaline (Figure 7h), and acidic (Figure 7i) media.

Figure 7

Figure 7. Absorption spectra of MB dye with Ag NWs, Ag–Ag₂S NWs, and graphene/Ag–Ag₂S (a,d,g) neutral medium (pH = 6); (b,e,h) alkaline medium (pH = 10); (c,f,i) acidic medium (pH = 3).

According to Equation 1, the average degradation efficiencies for each nanocatalyst at each pH –(Ag NWs -Figure 8A, Ag–Ag₂S NWs-Figure 8B, and graphene/Ag–Ag₂S -Figure 8C) are presented in Figure 8 and summarized in Table 1.

Figure 8

Figure 8. The average degradation efficiency of MB dye by Ag (A), Ag–Ag₂S (B) NWs, and (C) graphene/Ag–Ag₂S nanocatalysts.

Table 1

Table 1. The average degradation percentages (%) of MB dye by Ag, and Ag–Ag₂S, graphene/Ag–Ag₂S NWs. All the uncertainties were found to be less than 1%.

MB degradation was highest in acidic media. For Ag, it was 62.63% at pH 3 (5 h) versus 40.46% at pH 6 and less than or equal to 36.33% at pH 10 after 2 h. For Ag–Ag₂S NWs, the maximum was 68.27% at pH 3 (3 h; with no further change afterward), 59.77% at pH 6 (2 h), and 65.31% at pH 10 (3 h). For graphene/Ag–Ag₂S, it was 89.55% at pH 3 (5 h), 63.94% at pH 6, and 49.90% at pH 10 (5 h). In acidic conditions, (i) valence-band holes are stronger oxidants that efficiently generate ·OH/·O₂⁻, accelerating N-demethylation and ring-opening of cationic MB; (ii) Ag₂S captures visible/NIR light and, with Ag LSPR, enhances near-surface field intensity, boosting ROS formation; and (iii) graphene sheets in the hybrid facilitate e⁻ transport, reduce e⁻/h⁺ recombination (PL quenching/ higher photocurrent), and sustain ROS flux—together explaining the highest rate at pH 3 (Alaizeri et al., 2023; Mubarokah et al., 2023; Shokri Doodeji et al., 2024).

At neutral pH, activity decreases (Ag 40.46%; graphene/Ag–Ag₂S 63.94%) as hole oxidizing ability diminishes and adsorption becomes more influenced by surface charge. MB is mainly cationic, and its adsorption depends on the catalyst’s pH at the point of zero charge. Negative surfaces favor MB⁺ uptake, while protonated surfaces hinder electrostatic adsorption, leading to a lower local dye concentration at active sites and slower kinetics (Jaramillo-Fierro and Cuenca, 2024; Fito et al., 2023) (Alaizeri et al., 2023; Pradheesh et al., 2020). In alkaline conditions, two opposing effects occur. First, higher [OH⁻] levels can promote ·OH formation on some photocatalysts; second, Ag-based surfaces undergo pH-dependent transformations (transient Ag₂O/Ag–O species formation/dissolution; surface restructuring) and stronger product adsorption/passivation, which can stall progress (Ag stabilizing after 120 min).

The Ag–Ag₂S heterojunction partially compensates for these losses by enhancing charge separation (visible/NIR harvesting and interfacial band alignment), resulting in a relatively high efficiency of 65.31% at 180 min. Graphene further stabilizes reaction rates by improving adsorption (π–π interactions and van der Waals forces) and charge transport. However, excessive OH⁻ can still decrease net ROS availability on the surface and compete for active sites, which aligns with the lower efficiency of 49.90% at pH 10 (Mubarokah et al., 2023; Shokri Doodeji et al., 2024; Jaramillo-Fierro and Cuenca, 2024). Overall, acidic conditions maximize hole-driven oxidation and plasmon-assisted ROS generation, while neutral and alkaline environments introduce limitations related to adsorption and surface chemistry. The graphene/Ag–Ag₂S hybrid best alleviates these issues through improved MB uptake and reduced recombination (Alaizeri et al., 2023; Jaramillo-Fierro and Cuenca, 2024) (Pradheesh et al., 2020; Shokri Doodeji et al., 2024).

Photocatalytic kinetic rate constants (k_oβs, min⁻¹) and the coefficient of determination (R²) for each nanocatalyst across each medium (Ag NWs -Figure 9a, Ag–Ag₂S NWs-Figure 9b, and graphene/Ag–Ag₂S -Figure 9c) are presented in Figure 9.

Figure 9

Figure 9. Photocatalytic kinetic rate constants of MB by nanocatalysts (a) Ag NWs; (b) Ag–Ag₂S; (c) graphene/Ag–Ag₂S nanocatalysts.

Across all catalysts, ln(C₀/C) increases roughly linearly with time, supporting a pseudo-first-order model. The best linearity is observed for the graphene/Ag–Ag₂S hybrid (R² ≈ 0.89–0.92), while moderate fits are seen for pure Ag (R² ≈ 0.81–0.85). Ag–Ag₂S at pH 7 shows noticeable deviation (R² = 0.517). Rate constants (kobs, h^-1) reveal a clear activity ranking that depends on pH: under acidic conditions (pH 3), graphene/Ag–Ag₂S dominates with 0.5349, exceeding both Ag–Ag₂S (0.2781) and Ag (0.2517), resulting in approximately 2.1 times higher rates than Ag and Ag–Ag₂S. At neutral pH 7, the same order applies—0.2551 (graphene/Ag–Ag₂S) > 0.1518 (Ag–Ag₂S) > 0.1378 (Ag)—with about 1.9 times higher rates compared to Ag. In alkaline media (pH 10), however, Ag–Ag₂S (0.2779) outperforms both graphene/Ag–Ag₂S (0.1678) and Ag (0.1171), achieving roughly 2.4 times and 1.6 times higher rates, respectively. Overall, an acidic environment generally speeds up degradation for all materials. The graphene-modified hybrid delivers the highest kinetics at pH 3, and Ag–Ag₂S exhibits a notable performance boost at pH 10.

3.6 Limitations and perspectives

This study establishes the synthesis–structure–activity relationship of a graphene/Ag–Ag₂S hybrid toward methylene blue under controlled conditions, but it does not experimentally resolve the full degradation mechanism. The mechanistic rationale advanced here—plasmonic excitation in Ag, photoexcitation in Ag₂S, and graphene-mediated charge extraction with π–π enrichment of MB—remains a proposed pathway supported by literature rather than by new, dedicated diagnostics. In future work we will validate the dominant reactive oxygen species and charge-transfer sequence using dye-loaded spectroscopy (pre/post FT-IR or Raman), radical scavenger assays and ESR spin-trapping, and carrier-dynamics probes such as steady-state or time-resolved photoluminescence and electrochemical impedance. By separating adsorption from photoreaction and correlating spectral changes with kinetic signatures, these measurements will convert the present mechanistic proposal into direct experimental evidence.

The present report does not include reusability testing or long-term stability analysis. The study was performed on a small test batch synthesized to confirm composition, phases, and baseline photocatalytic response; this limited mass was insufficient to support statistically powered multi-cycle experiments alongside characterization. We therefore refrain from making durability claims. Subsequent work will scale the synthesis to enable repeated-use studies under identical conditions with triplicate measurements, report mean ± standard deviation for degradation efficiencies and apparent rate constants, annotate kinetic fits with R2, and examine post-reaction integrity by XRD, XPS, and FT-IR. Silver leaching will be quantified to verify heterogeneous operation, and any efficiency decay will be mapped to specific failure modes such as photocorrosion, surface fouling, or phase evolution.

Finally, we did not evaluate performance in industrial wastewater matrices. This is intentional to isolate intrinsic activity and avoid matrix-dependent artifacts in an initial materials report. Real-sample validation will be followed by testing representative effluents alongside standard MB solutions to quantify matrix effects from pH, ionic strength, turbidity, and co-contaminants. Spike-and-recovery protocols will be used to assess accuracy, total organic carbon or chemical oxygen demand will be monitored to gauge mineralization beyond decolorization, and catalyst integrity and leaching will be checked after treatment. These steps will translate the present proof-of-concept into a deployable treatment strategy while preserving the rigor of controlled benchmarking.

4 Conclusion

A robust 2D/1D graphene/Ag–Ag₂S photocatalyst was successfully synthesized and validated through complementary characterization methods. SEM revealed a core–shell Ag–Ag₂S structure on 1D NWs decorating 2D graphene. XRD confirmed the presence of fcc-Ag along with acanthite Ag₂S and Ag₂O. UV–Vis results showed LSPR suppression and broadening upon shelling, with π–π* dominated absorption in the hybrid, as seen in the UV-Vis spectrum and Tauc plots indicating multiphase band structures (E.g., ∼3.28/4.72 eV), which are advantageous for interfacial charge separation. FTIR verified Ag–S/Ag–O bonding alongside graphene signatures. These structure–property relationships explain the photocatalytic performance: (i) Ag LSPR supplies hot carriers; (ii) Ag–Ag₂S heterojunctions promote charge separation; and (iii) graphene enhances electron transport and dye adsorption. As a result, the hybrid achieved the fastest MB degradation in acidic media (pH 3: kobs = 0.5349 h⁻¹; 89.55% in 5 h), surpassing both Ag–Ag₂S and Ag. Performance was moderated at neutral pH with the same activity order, while alkaline conditions favored Ag–Ag₂S (kobs = 0.2779 h⁻¹) as surface chemistry and site competition reduced graphene’s advantage. The characterization confirms successful hybrid formation and explains its pH-responsive, high-efficiency dye removal, positioning graphene/Ag–Ag₂S as a tunable platform for wastewater remediation, with Ag–Ag₂S alone recommended for alkaline streams.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Author contributions

TT: Conceptualization, Data curation, Formal Analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review and editing. LG: Conceptualization, Data curation, Formal Analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review and editing. MM: Writing – original draft, Writing – review and editing. MB: Writing – original draft, Writing – review and editing. GE: Writing – original draft, Writing – review and editing. SB: Writing – original draft, Writing – review and editing. JMT: Writing – original draft, Writing – review and editing. CVG: Conceptualization, Data curation, Formal Analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review and editing. RK: Writing – original draft, Writing – review and editing. LC: Writing – original draft, Writing – review and editing. SS: Writing – original draft, Writing – review and editing.

Funding

The authors declare that financial support was received for the research and/or publication of this article. The article processing charge of this work has been supported by Universidad Técnica Particular de Loja. SB is supported in part by a project funded by Romania’s National Recovery and, Romania’s National Recovery and Resilience Plan (PNRR), component C9. Support for the private sector, research, development, and innovation “I8. Development of a program to attract highly specialised human resources from abroad in research, development, and innovation activities, entitled “Composite materials for applications in the water management field”, ID - 11/26.07.2023, contract number 760270/26.03.2024.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The authors declare that Generative AI was used in the creation of this manuscript. ChatGPT 4o and Grammarly for English improvement.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

References

Abouelela, M. M., Kawamura, G., and Matsuda, A. (2021). A review on plasmonic nanoparticle-semiconductor photocatalysts for water splitting. J. Clean. Prod. 294, 126200. doi:10.1016/j.jclepro.2021.126200

CrossRef Full Text | Google Scholar

Alaizeri, Z. M., Alhadlaq, H. A., Aldawood, S., Akhtar, M. J., Aziz, A. A., and Ahamed, M. (2023). Photocatalytic degradation of methylene blue and anticancer response of In2O3/RGO nanocomposites prepared by a microwave-assisted hydrothermal synthesis process. Molecules 28 (13), 5153. doi:10.3390/molecules28135153

PubMed Abstract | CrossRef Full Text | Google Scholar

Almarashi, J. Q., Gadallah, A. S., Shaban, M., Ellabban, M. A., Hbaieb, K., Kordy, M. G., et al. (2024). Quick methylene blue dye elimination via SDS-Ag nanoparticles catalysts. Sci. Rep. 14 (1), 15227. doi:10.1038/s41598-024-65491-6

PubMed Abstract | CrossRef Full Text | Google Scholar

Alsalme, A., Najm, A., Mohammed, N. N., Messih, M. A., Sultan, A., and Ahmed, M. A. (2024). Rational fabrication of Ag2S/g-C3N4 heterojunction for photocatalytic degradation of rhodamine B dye under natural solar radiation. Catalysts 14 (12), 914. doi:10.3390/catal14120914

CrossRef Full Text | Google Scholar

Amirjani, A., Amlashi, N. B., and Ahmadiani, Z. S. (2023). Plasmon-enhanced photocatalysis based on plasmonic nanoparticles for energy and environmental solutions: a review. ACS Appl. Nano Mater. 6 (11), 9085–9123. doi:10.1021/acsanm.3c01671

CrossRef Full Text | Google Scholar

Baghirov, M. B., Muradov, M., Eyvazova, G., Mammadyarova, S., Azizian-Kalandaragh, Y., Musayeva, N., et al. (2024). Preparation of anisotropic AgNWs/PVA/Ag 2 S nanocomposites via a vapor-phase sulfidation process. RSC Adv. 14 (24), 16696–16703. doi:10.1039/d4ra01585a

PubMed Abstract | CrossRef Full Text | Google Scholar

Balamurugan, B., and Maruyama, T. (2005). Plasmon resonance of Ag nanoparticles in glass thin films. Appl. Phys. Lett. 87 (14), 143105. doi:10.1063/1.2077834

CrossRef Full Text | Google Scholar

Billy, D. O., Tariq, A., Richards, B. D. O., Jose, G., Krasnikov, S. A., Kulak, A., et al. (2017). White light-induced covalent modification of graphene using a phenazine dye. Chem. Commun. 53 (77), 10715–10718. doi:10.1039/c7cc05158a

CrossRef Full Text | Google Scholar

Bolotin, K. I., Sikes, K. J., Hone, J., Stormer, H. L., and Kim, P. (2008). Temperature-dependent transport in suspended graphene. Phys. Rev. Lett. 101 (9), 096802. doi:10.1103/physrevlett.101.096802

PubMed Abstract | CrossRef Full Text | Google Scholar

Boussaida, B., and Masrour, R. (2023). Modelling of the structural, electronic, magnetic properties and magnetocaloric effect of Cr2Ge2Te6 and Cr2Si2Te6 compounds: DFT combined with the monte carlo method. Mol. Phys. 121 (6), e2197522. doi:10.1080/00268976.2023.2197522

CrossRef Full Text | Google Scholar

Castro Neto, A. H., Guinea, F., Peres, N. M., Novoselov, K. S., and Geim, A. K. (2009). The electronic properties of graphene. Rev. Mod. Phys. 81 (1), 109–162. doi:10.1103/RevModPhys.81.1094

CrossRef Full Text | Google Scholar

Chen, Y. C., Gregori, G., Rheingans, B., Huang, W., Kronmüller, H., Schütz, G., et al. (2020). Magnetic and microstructural properties of anisotropic MnBi magnets compacted by spark plasma sintering. J. Alloys Compd. 830, 154605. doi:10.1016/j.jallcom.2020.154605

CrossRef Full Text | Google Scholar

Cirit, E. S., Akyuz, S. A., Bilir, A., Dumanli, S., Can, V., and Canbek Ozdil, Z. C. (2024). Optimizing silver nanowire synthesis for In-Body applications. ACS Appl. Nano Mater. 7 (7), 8130–8139. doi:10.1021/acsanm.4c00625

CrossRef Full Text | Google Scholar

Collado, L., Reynal, A., Fresno, F., Barawi, M., Escudero, C., Perez-Dieste, V., et al. (2018). Unravelling the effect of charge dynamics at the plasmonic metal/semiconductor interface for CO2 photoreduction. Nat. Commun. 9 (1), 4986. doi:10.1038/s41467-018-07397-2

PubMed Abstract | CrossRef Full Text | Google Scholar

Darvishi, M., and Seyed-Yazdi, J. (2016). Effect of microwave power on created defects in graphene sheet of synthesized TiO2/graphene nanocomposite with enhanced photocatalytic performance. Surfaces Interfaces 4, 1–8. doi:10.1016/j.surfin.2016.07.001

CrossRef Full Text | Google Scholar

Ditlbacher, H., Hohenau, A., Wagner, D., Kreibig, U., Rogers, M., Hofer, F., et al. (2005). Silver nanowires as surface plasmon resonators. Phys. Rev. Lett. 95 (25), 257403. doi:10.1103/physrevlett.95.257403

PubMed Abstract | CrossRef Full Text | Google Scholar

Dreyer, D. R., Park, S., Bielawski, C. W., and Ruoff, R. S. (2010). The chemistry of graphene oxide. Chem. Soc. Rev. 39 (1), 228–240. doi:10.1039/b917103g

PubMed Abstract | CrossRef Full Text | Google Scholar

Eda, G., and Chhowalla, M. (2010). Chemically derived graphene oxide: towards large-area thin-film electronics and optoelectronics. Adv. Mater. 22 (22), 2392–2415. doi:10.1002/adma.200903689

PubMed Abstract | CrossRef Full Text | Google Scholar

Eswari, K. M., Asaithambi, S., Karuppaiah, M., Sakthivel, P., Balaji, V., Ponelakkia, D. K., et al. (2022). Green synthesis of ZnO nanoparticles using Abutilon indicum and Tectona Grandis leaf extracts for evaluation of anti-diabetic, anti-inflammatory, and in-vitro cytotoxicity activities. Ceram. Int. 48 (22), 33624–33634. doi:10.1016/j.ceramint.2022.07.308

CrossRef Full Text | Google Scholar

Fito, J., Abewaa, M., Mengistu, A., Angassa, K., Ambaye, A. D., Moyo, W., et al. (2023). Adsorption of methylene blue from textile industrial wastewater using activated carbon developed from Rumex abyssinicus plant. Sci. Rep. 13 (1), 5427. doi:10.1038/s41598-023-32341-w

PubMed Abstract | CrossRef Full Text | Google Scholar

Gahramanli, L. R., Muradov, M. B., Kim, J., Eyvazova, G. M., Gasimov, E. K., Rzayev, F. H., et al. (2024a). Enhanced adsorption and degradation kinetics of methylene blue by Ag–Ag2S–CdS hybrid nanowires. Opt. Mater. 154, 115760. doi:10.1016/j.optmat.2024.115760

CrossRef Full Text | Google Scholar

Gahramanli, L. R., Muradov, M. B., Kim, J., Eyvazova, G. M., Gasimov, E. K., Rzayev, F. H., et al. (2024b). Ag–Ag2S–CdS nanostructures: formation, physical characteristics, and role in methylene blue removal. J. Mater. Sci. Mater. Electron. 35 (27), 1799. doi:10.1007/s10854-024-13539-8

CrossRef Full Text | Google Scholar

Gahramanli, L. R., Bellucci, S., Muradov, M. B., Pietra, M. L., Eyvazova, G. M., Gomez, C. V., et al. (2024c). Synthesis and physical characterization of novel Ag 2 S-CdS/Ag/GNP ternary nanocomposite. Chalcogenide Lett. 21 (7), 513–527. doi:10.15251/cl.2024.217.513

CrossRef Full Text | Google Scholar

Gahramanli, L., Muradov, M., Baghirov, M., Eyvazova, G., Bellucci, S., Gomez, C. V., et al. (2025). Synthesis, characterization, and photocatalytic performance of 2D/1D graphene/Ag–Ag 2 S hybrid nanocomposites. Dalton Trans. 54, 15118–15133. doi:10.1039/d5dt01999k

PubMed Abstract | CrossRef Full Text | Google Scholar

Gallardo, O. A. D., Moiraghi, R., Macchione, M. A., Godoy, J. A., Pérez, M. A., Coronado, E. A., et al. (2012). Silver oxide particles/silver nanoparticles interconversion: susceptibility of forward/backward reactions to the chemical environment at room temperature. Rsc Adv. 2 (7), 2923–2929. doi:10.1039/c2ra01044e

CrossRef Full Text | Google Scholar

Gao, Y., Song, L., Jiang, P., Liu, L. F., Yan, X. Q., Zhou, Z. P., et al. (2005). Silver nanowires with five-fold symmetric cross-section. J. Cryst. growth 276 (3-4), 606–612. doi:10.1016/j.jcrysgro.2004.11.396

CrossRef Full Text | Google Scholar

Gebeyehu, M. B., Chala, T. F., Chang, S. Y., Wu, C. M., and Lee, J. Y. (2017). Synthesis and highly effective purification of silver nanowires to enhance transmittance at low sheet resistance with simple polyol and scalable selective precipitation method. RSC Adv. 7 (26), 16139–16148. doi:10.1039/c7ra00238f

CrossRef Full Text | Google Scholar

Gubicza, A., Manrique, D. Z., Pósa, L., Lambert, C. J., Mihály, G., Csontos, M., et al. (2016). Asymmetry-induced resistive switching in Ag-Ag2S-Ag memristors enabling a simplified atomic-scale memory design. Sci. Rep. 6 (1), 30775. doi:10.1038/srep30775

PubMed Abstract | CrossRef Full Text | Google Scholar

Gusev, A. I., and Sadovniov, S. I. (2017). Structure and properties of nanoscale Ag2S/Ag heterostructure. Mater. Lett. 188, 351–354. doi:10.1016/j.matlet.2016.11.111

CrossRef Full Text | Google Scholar

Hadi, A., Zahirifar, J., Karimi-Sabet, J., and Dastbaz, A. (2018). Graphene nanosheets preparation using magnetic nanoparticle-assisted liquid phase exfoliation of graphite: the coupled effect of ultrasound and wedging nanoparticles. Ultrason. sonochemistry 44, 204–214. doi:10.1016/j.ultsonch.2018.02.028

PubMed Abstract | CrossRef Full Text | Google Scholar

Hu, W., Zhao, L., Zhang, Y., Zhang, X., Dong, L., Wang, S., et al. (2016). Preparation and photocatalytic activity of graphene-modified Ag2S composite. J. Exp. Nanosci. 11 (6), 433–444. doi:10.1080/17458080.2015.1077533

CrossRef Full Text | Google Scholar

Huang, F., Zhang, X., Chang, Y., Chen, W., Wu, H., Li, L., et al. (2024). Construction of Ag2S@ CdS pn heterojunction for efficient visible light photocatalytic oxidative coupling of benzylamines to imines. Mol. Catal. 556, 113928. doi:10.1016/j.mcat.2024.113928

CrossRef Full Text | Google Scholar

Ickecan, D., Zan, R., and Nezir, S. (2017). Eco-friendly synthesis and characterization of reduced graphene oxide. J. Phys. Conf. Ser. 902 1. 012027. doi:10.1088/1742-6596/902/1/012027

CrossRef Full Text | Google Scholar

Jana, N. R., Gearheart, L., and Murphy, C. J. (2001). Wet chemical synthesis of silver nanorods and nanowires of controllable aspect ratioElectronic supplementary information (ESI) available: UV–VIS spectra of silver nanorods. Chem. Commun. (7), 617–618. doi:10.1039/b100521i

CrossRef Full Text | Google Scholar

Jaramillo-Fierro, X., and Cuenca, G. (2024). Enhancing methylene blue removal through adsorption and photocatalysis—a study on the Go/ZnTiO3/TiO2 composite. Int. J. Mol. Sci. 25 (8), 4367. doi:10.3390/ijms25084367

PubMed Abstract | CrossRef Full Text | Google Scholar

Jiang, Q., Zeng, W., Zhang, C., Meng, Z., Wu, J., Zhu, Q., et al. (2017). Broadband absorption and enhanced photothermal conversion property of octopod-like Ag@ Ag2S core@ shell structures with gradually varying shell thickness. Sci. Rep. 7 (1), 17782. doi:10.1038/s41598-017-18220-1

PubMed Abstract | CrossRef Full Text | Google Scholar

Katheresan, V., Kansedo, J., and Lau, S. Y. (2018). Efficiency of various recent wastewater dye removal methods: a review. J. Environ. Chem. Eng. 6 (4), 4676–4697. doi:10.1016/j.jece.2018.06.060

CrossRef Full Text | Google Scholar

Kaushal, J., Mahajan, P., and Kaur, N. (2021). A review on application of phytoremediation technique for eradication of synthetic dyes by using ornamental plants. Environ. Sci. Pollut. Res. 28 (48), 67970–67989. doi:10.1007/s11356-021-16672-7

PubMed Abstract | CrossRef Full Text | Google Scholar

Khan, I., Saeed, K., Zekker, I., Zhang, B., Hendi, A. H., Ahmad, A., et al. (2022). Review on methylene blue: its properties, uses, toxicity, and photodegradation. Water 14 (2), 242. doi:10.3390/w14020242

CrossRef Full Text | Google Scholar

Kharlamova, M. V., and Kramberger, C. (2022). Metal and metal halogenide-filled single-walled carbon nanotubes: Kinetics, electronic properties, engineering the fermi level. Nanomaterials 13 (1), 180. doi:10.3390/nano13010180

PubMed Abstract | CrossRef Full Text | Google Scholar

Khezrianjoo, S., and Revanasiddappa, H. D. (2012). Langmuir-hinshelwood kinetic expression for the photocatalytic degradation of metanil yellow aqueous solutions by ZnO catalyst. Chem. Sci. J.

Google Scholar

B. König (2013). Chemical photocatalysis (Berlin, Germany: Walter de Gruyter GmbH and Company KG).

Google Scholar

Kumar, M., Devi, P., and Kumar, A. (2017). Structural analysis of PVP-Capped silver nanoparticles synthesized at room temperature for optical, electrical, and gas sensing properties. J. Mater. Sci. Mater. Electron. 28 (6), 5014–5020. doi:10.1007/s10854-016-6157-y

CrossRef Full Text | Google Scholar

Lee, C., Wei, X., Kysar, J. W., and Hone, J. (2008). Measurement of the elastic properties and intrinsic strength of monolayer graphene. science 321 (5887), 385–388. doi:10.1126/science.1157996

PubMed Abstract | CrossRef Full Text | Google Scholar

Li, M., Cushing, S. K., and Wu, N. (2015). Plasmon-enhanced optical sensors: a review. Analyst 140 (2), 386–406. doi:10.1039/c4an01079e

PubMed Abstract | CrossRef Full Text | Google Scholar

Liu, Y., Chen, J., Zhang, J., Tang, Z., Li, H., and Yuan, J. (2020). Z-scheme BiVO 4/Ag/Ag 2 S composites with enhanced photocatalytic efficiency under visible light. RSC Adv. 10 (51), 30245–30253. doi:10.1039/d0ra05712f

PubMed Abstract | CrossRef Full Text | Google Scholar

Liz-Marzán, L. M. (2006). Tailoring surface plasmons through the morphology and assembly of metal nanoparticles. Langmuir 22 (1), 32–41. doi:10.1021/la0513353

PubMed Abstract | CrossRef Full Text | Google Scholar

Mcoyi, M. P., Mpofu, K. T., Sekhwama, M., and Mthunzi-Kufa, P. (2025). Developments in localized surface plasmon resonance. Plasmonics 20 (7), 5481–5520. doi:10.1007/s11468-024-02620-x

CrossRef Full Text | Google Scholar

Mohamadpour, F., and Amani, A. M. (2024). Photocatalytic systems: reactions, mechanism, and applications. RSC Adv. 14 (29), 20609–20645. doi:10.1039/d4ra03259d

PubMed Abstract | CrossRef Full Text | Google Scholar

Mubarokah, Z. R., Mahmed, N., Norizan, M. N., Mohamad, I. S., Abdullah, M. M. A. B., Błoch, K., et al. (2023). Near-infrared (NIR) silver sulfide (Ag2S) semiconductor photocatalyst film for degradation of methylene blue solution. Materials 16 (1), 437. doi:10.3390/ma16010437

PubMed Abstract | CrossRef Full Text | Google Scholar

Muhd Julkapli, N., Bagheri, S., and Bee Abd Hamid, S. (2014). Recent advances in heterogeneous photocatalytic decolorization of synthetic dyes. Sci. World J. 2014 (1), 1–25. doi:10.1155/2014/692307

PubMed Abstract | CrossRef Full Text | Google Scholar

Nair, R. R., Blake, P., Grigorenko, A. N., Novoselov, K. S., Booth, T. J., Stauber, T., et al. (2008). Fine structure constant defines visual transparency of graphene. science 320 (5881), 1308. doi:10.1126/science.1156965

PubMed Abstract | CrossRef Full Text | Google Scholar

Negash, A., Mohammed, S., Weldekirstos, H. D., Ambaye, A. D., and Gashu, M. (2023). Enhanced photocatalytic degradation of methylene blue dye using eco-friendly synthesized rGO@ ZnO nanocomposites. Sci. Rep. 13 (1), 22234. doi:10.1038/s41598-023-48826-7

PubMed Abstract | CrossRef Full Text | Google Scholar

Peana, M., Pelucelli, A., Chasapis, C. T., Perlepes, S. P., Bekiari, V., Medici, S., et al. (2022). Biological effects of human exposure to environmental cadmium. Biomolecules 13 (1), 36. doi:10.3390/biom13010036

PubMed Abstract | CrossRef Full Text | Google Scholar

Pradheesh, G., Suresh, S., Suresh, J., and Alexramani, V. (2020). Antimicrobial and anticancer activity studies on green synthesized silver oxide nanoparticles from the medicinal plant Cyathea nilgiriensis holttum. Int. J. Pharm. Investigation 10 (2), 146–150. doi:10.5530/ijpi.2020.2.27

CrossRef Full Text | Google Scholar

Pradyasti, A., Kim, D. H., Biutty, M. N., Yoo, S. I., and Kim, M. H. (2020). Ag–Ag2S hybrid nanoplates with unique heterostructures: facile synthesis and photocatalytic application. J. Alloys Compd. 826, 154191. doi:10.1016/j.jallcom.2020.154191

CrossRef Full Text | Google Scholar

Sadovnikov, S. I., and Gerasimov, E. Y. (2019). Direct TEM observation of the “acanthite α-Ag 2 S–argentite β-Ag 2 S” phase transition in a silver sulfide nanoparticle. Nanoscale Adv. 1 (4), 1581–1588. doi:10.1039/c8na00347e

PubMed Abstract | CrossRef Full Text | Google Scholar

Sadovnikov, S. I., Kuznetsova, Y. V., and Rempel, A. A. (2016). Ag2S silver sulfide nanoparticles and colloidal solutions: synthesis and properties. Nano-Structures and Nano-Objects 7, 81–91. doi:10.1016/j.nanoso.2016.06.004

CrossRef Full Text | Google Scholar

Scarpa, F., Adhikari, S., and Phani, A. S. (2009). Effective elastic mechanical properties of single-layer graphene sheets. Nanotechnology 20 (6), 065709. doi:10.1088/0957-4484/20/6/065709

PubMed Abstract | CrossRef Full Text | Google Scholar

Shafi, A., Ahmad, N., Sultana, S., Sabir, S., and Khan, M. Z. (2019). Ag2S-sensitized NiO–ZnO heterostructures with enhanced visible light photocatalytic activity and acetone sensing property. ACS omega 4 (7), 12905–12918. doi:10.1021/acsomega.9b01261

PubMed Abstract | CrossRef Full Text | Google Scholar

Shahjamali, M. M., Zhou, Y., Zaraee, N., Xue, C., Wu, J., Large, N., et al. (2016). Ag–Ag2S hybrid nanoprisms: structural versus plasmonic evolution. Acs Nano 10 (5), 5362–5373. doi:10.1021/acsnano.6b01532

PubMed Abstract | CrossRef Full Text | Google Scholar

Shakoor, M. H., Shakoor, M. B., Jilani, A., Ahmed, T., Rizwan, M., Dustgeer, M. R., et al. (2024). Enhancing the photocatalytic degradation of methylene blue with graphene oxide-encapsulated g-C3N4/ZnO ternary composites. ACS omega 9 (14), 16187–16195. doi:10.1021/acsomega.3c10172

PubMed Abstract | CrossRef Full Text | Google Scholar

Shokri Doodeji, M., Afzalzadeh, A., and Zerafat, M. M. (2024). Fabrication of Ag nanowires and Ag-graphite nanocomposite conductive adhesives by one-step hydrothermal method. J. Mater. Sci. Mater. Electron. 35 (22), 1543. doi:10.1007/s10854-024-13321-w

CrossRef Full Text | Google Scholar

Simonnin, P., Sassi, M., Gilbert, B., Charlet, L., and Rosso, K. M. (2020). Phase transition and liquid-like superionic conduction in Ag2S. J. Phys. Chem. C 124 (18), 10150–10158. doi:10.1021/acs.jpcc.0c00260

CrossRef Full Text | Google Scholar

Siong, V. L. E., Lee, K. M., Juan, J. C., Lai, C. W., Tai, X. H., and Khe, C. S. (2019). Removal of methylene blue dye by solvothermally reduced graphene oxide: a metal-free adsorption and photodegradation method. RSC Adv. 9 (64), 37686–37695. doi:10.1039/c9ra05793e

PubMed Abstract | CrossRef Full Text | Google Scholar

Tatsuma, T., Nishi, H., and Ishida, T. (2017). Plasmon-induced charge separation: chemistry and wide applications. Chem. Sci. 8 (5), 3325–3337. doi:10.1039/c7sc00031f

PubMed Abstract | CrossRef Full Text | Google Scholar

Trukhanov, S. V., Lobanovski, L. S., Bushinsky, M. V., Khomchenko, V. A., Fedotova, V. V., Troyanchuk, I. O., et al. (2007). Microstructure evolution and magnetoresistance of the A-site ordered Ba-doped manganites. Semiconductors 41 (5), 507–511. doi:10.1134/s1063782607050041

CrossRef Full Text | Google Scholar

Tseng, K. H., Yeh, C. T., Chung, M. Y., Lin, Y. S., and Qui, N. (2021). A study of preparing silver iodide nanocolloid by electrical spark discharge method and its properties. Sci. Rep. 11 (1), 20457. doi:10.1038/s41598-021-99976-5

PubMed Abstract | CrossRef Full Text | Google Scholar

Uzek, R. (2024). Engineering a graphene quantum dot-enhanced surface plasmon resonance sensor for ultra-sensitive detection of Hg 2+ ions. Adv. Mater. INTERFACES. doi:10.1002/admi.202400679

CrossRef Full Text | Google Scholar

Wang, K., Yu, L., Yin, S., Li, H., and Li, H. (2009). Photocatalytic degradation of methylene blue on magnetically separable FePc/Fe3O4 nanocomposite under visible irradiation. Pure Appl. Chem. 81 (12), 2327–2335. doi:10.1351/pac-con-08-11-23

CrossRef Full Text | Google Scholar

Wang, M., Wang, Y., Tang, A., Li, X., Hou, Y., and Teng, F. (2012). Optical properties and self-assembly of Ag2S nanoparticles synthesized by a one-pot method. Mater. Lett. 88, 108–111. doi:10.1016/j.matlet.2012.08.027

CrossRef Full Text | Google Scholar

Wang, Q., Wang, Y., Meng, Q., Wang, T., Guo, W., Wu, G., et al. (2017). Preparation of high antistatic HDPE/Polyaniline encapsulated graphene nanoplatelet composites by solution blending. RSC Adv. 7 (5), 2796–2803. doi:10.1039/c6ra26458a

CrossRef Full Text | Google Scholar

Wang, F., Zhang, H., Song, X., Li, H., Xu, Z., Wei, D., et al. (2022). High-responsivity vis–NIR photodetector based on a Ag2S/CsPbBr3 heterojunction. ACS Appl. Electron. Mater. 4 (8), 3922–3929.

Google Scholar

Wang, S., Liu, H., Pan, Y., Xie, F., Zhang, Y., Zhao, J., et al. (2022). Performance enhancement of silver nanowire-based transparent electrodes by ultraviolet irradiation. Nanomaterials 12 (17), 2956. doi:10.3390/nano12172956

PubMed Abstract | CrossRef Full Text | Google Scholar

Wang, Y., Liu, Y., Zhang, H., Duan, X., Ma, J., Sun, H., et al. (2025). Carbonaceous materials in structural dimensions for advanced oxidation processes. Chem. Soc. Rev. 54, 2436–2482. doi:10.1039/d4cs00338a

PubMed Abstract | CrossRef Full Text | Google Scholar

Wiley, B. J., Im, S. H., Li, Z. Y., McLellan, J., Siekkinen, A., and Xia, Y. (2006). Maneuvering the surface plasmon resonance of silver nanostructures through shape-controlled synthesis. J. Phys. Chem. B 110 (32), 15666–15675. doi:10.1021/jp0608628

PubMed Abstract | CrossRef Full Text | Google Scholar

Xiang, J., Cao, H., Wu, Q., Zhang, S., Zhang, X., and Watt, A. A. (2008). L-cysteine-assisted synthesis and optical properties of Ag2S nanospheres. J. Phys. Chem. C 112 (10), 3580–3584. doi:10.1021/jp710597j

CrossRef Full Text | Google Scholar

Xin, G., Yao, T., Sun, H., Scott, S. M., Shao, D., Wang, G., et al. (2015). Highly thermally conductive and mechanically strong graphene fibers. Science 349 (6252), 1083–1087. doi:10.1126/science.aaa6502

PubMed Abstract | CrossRef Full Text | Google Scholar

Xiong, J., Han, C., Li, W., Sun, Q., Chen, J., Chou, S., et al. (2016). Ambient synthesis of a multifunctional 1D/2D hierarchical Ag–Ag 2 S nanowire/nanosheet heterostructure with diverse applications. CrystEngComm 18 (6), 930–937. doi:10.1039/c5ce02134k

CrossRef Full Text | Google Scholar

Yang, L., Huang, X., Wu, H., Liang, Y., Ye, M., Liu, W., et al. (2023). Silver nanowires: from synthesis, growth mechanism, device fabrication to prospective engineered applications. Eng. Sci. 23 (3), 808.

Google Scholar

Zamiri, R., Abbastabar Ahangar, H., Zakaria, A., Zamiri, G., Shabani, M., Singh, B., et al. (2015). The structural and optical constants of Ag 2 S semiconductor nanostructure in the Far-infrared. Chem. Central J. 9, 28–6. doi:10.1186/s13065-015-0099-y

PubMed Abstract | CrossRef Full Text | Google Scholar

Zhang, N., Li, M., Tan, C. F., Peh, C. K. N., Sum, T. C., and Ho, G. W. (2017). Plasmonic enhanced photoelectrochemical and photocatalytic performances of 1D coaxial Ag@ Ag 2 S hybrids. J. Mater. Chem. A 5 (40), 21570–21578. doi:10.1039/c7ta06473j

CrossRef Full Text | Google Scholar

Zhang, S., Wang, J., Chen, S., Li, R., and Peng, T. (2019). Construction of Ag2S/WO3 direct Z-scheme photocatalyst for enhanced charge separation efficiency and H2 generation activity. Industrial and Eng. Chem. Res. 58 (32), 14802–14813. doi:10.1021/acs.iecr.9b02335

CrossRef Full Text | Google Scholar

Zhao, G., Li, X., Huang, M., Zhen, Z., Zhong, Y., Chen, Q., et al. (2017). The physics and chemistry of graphene-on-surfaces. Chem. Soc. Rev. 46 (15), 4417–4449. doi:10.1039/c7cs00256d

PubMed Abstract | CrossRef Full Text | Google Scholar

Zhen, Z., and Zhu, H. (2018). “Structure and properties of graphene,” in Graphene (Academic Press), 1–12.

Google Scholar

Zhou, S., and Bongiorno, A. (2013). Origin of the chemical and kinetic stability of graphene oxide. Sci. Rep. 3 (1), 2484. doi:10.1038/srep02484

PubMed Abstract | CrossRef Full Text | Google Scholar

Zhu, D., Tang, A., Ye, H., Wang, M., Yang, C., and Teng, F. (2015). Tunable near-infrared localized surface plasmon resonances of djurleite nanocrystals: effects of size, shape, surface-ligands, and oxygen exposure time. J. Mater. Chem. C 3 (26), 6686–6691. doi:10.1039/c5tc01310k

CrossRef Full Text | Google Scholar