Advanced electrocatalysts and mass transport optimization for PEM electrolyzers

Advanced electrocatalysts and mass transport optimization for PEM electrolyzers

Hydrogen energy offers substantial environmental benefits and contributes to the global objective of achieving carbon neutrality, while providing a secure and sustainable source of clean energy. As solar and wind energy are deployed at scale, hydrogen has also emerged as a versatile carrier for converting intermittent renewables into storable chemical energy. Among hydrogen production methods, proton exchange membrane water electrolysis (PEMWE) stands out as a leading technology for large-scale deployment, owing to its compact design, high hydrogen purity, low internal resistance, and rapid dynamic response. While advancing the design of efficient water-splitting electrocatalysts and developing robust, high-performance electrolysis devices are essential steps toward the scalable adoption of PEMWE.

Currently, the pursuit of higher energy efficiency in water electrolysis is primarily addressed through three interrelated research domains: (i) the design and scalable synthesis of efficient hydrogen evolution reaction (HER) catalysts; (ii) the design and scalable synthesis of efficient oxygen evolution reaction (OER) catalysts; and (iii) the optimization of mass transport within electrolyzers. The overpotential associated with HER catalysts has been substantially reduced, yet practical catalyst development remains largely dominated by platinum-based systems. By contrast, OER catalysts continue to exhibit sizable overpotentials and face notable stability challenges. Meanwhile, mass transport processes in electrolyzers are often not directly observable, and robust, model-based understanding remains limited.

Recent advances are gradually expanding our understanding of the mechanisms underlying the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). For instance, the influence of interfacial water structure on catalytic processes has attracted increasing attention. Studies on the structural evolution of catalysts are prompting researchers to reassess the nature of catalytically active sites and to deepen their understanding of catalyst stability. Non-precious-metal-based OER catalysts are expected to exhibit improved stability under PEMWE operating conditions. Optimizing gas–liquid mass transfer in PEMWEs is also crucial for enhancing overall energy efficiency.

The scope of this issue encompasses: (i) the design, synthesis, and scalable production of efficient catalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER); (ii) investigations into catalytic mechanisms and their implications; (iii) studies of catalyst structural evolution and strategies to enhance long-term stability; (iv) the mechanistic role of interfacial water structures in HER and OER; (v) applications and design strategies for non-noble-metal catalysts in OER; and (vi) research methodologies and theoretical frameworks related to the design of PEM electrolyzers, with particular emphasis on mass-transfer kinetics. Submissions may include original research articles, reviews, or perspective papers.