AUTHOR=Yan W. J. , Zheng Y. F. , Zhou T. W. , Wang G. Z. , Wang D. D. , Yuan H. K. 

TITLE=Formation of a Key Intermediate Complex Species in Catalytic Hydrolysis of NH3BH3 by Bimetal Clusters: Metal-Dihydride and Boron-Multihydroxy

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00604

DOI=10.3389/fchem.2020.00604

ISSN=2296-2646

ABSTRACT=The hydrolysis of AB (AB, NH3BH3) with the help of transition metal catalysts have been identified as one of the promising strategies for dehydrogenation in numerous experiments. Although
great progress has been achieved in experiments, the evaluation of the B-N bond cleavage channel
as well as the hydrogen transfer channel has not been performed to gain a deep understanding
of the kinetic route. Based on the density functional theory (DFT) calculation, we presented a
clear mechanistic study on the hydrolytic reaction of AB by choosing a smallest NiCu cluster as
the model catalyst. Two attacking types of water molecules are considered for the hydrolytic
reaction of AB: stepwise and simultaneous adsorption on the catalyst for reactions. The Ni and
Cu metal atoms play the distinctive roles in catalytic activity, i.e., Ni atom takes reactions for
H2O decomposition with the formation of [OH]− group whereas Cu atom takes reactions for hydride transfer with the formation of metal-dihydride complex. The formation of Cu-dihydride &
B-multihydroxy complex is the prerequisite for effectively hydrolytic dehydrogenation of AB. By
analyzing the maximum barrier height in the pathway which determines the kinetic rates, we found
that the hydride hydrogen transferring rather than the N-B bond breaking is responsible to the
experimentally measured activation energy barrier.