International Journal of Hydrogen Energy, Vol.44, No.16, 8307-8314, 2019
Transition metal tuned semiconductor photocatalyst CuCo/beta-SiC catalyze hydrolysis of ammonia borane to hydrogen evolution
In the study, a novel approach of Cu, Co tuned photocatalyst beta-SiC catalyze hydrolysis of ammonia borane was proposed as a means to boost H-2 evolution. Electronic properties including band structure and DOS of beta-SiC and CuCo/beta-SiC are calculated. In addition, the hydrolysis mechanism of AB and photocatalytic boosting mechanism of AB hydrolysis on the catalyst CuCo/beta-SiC are discussed. The systematic investigation showed that the transition metal atom (Cu, Co) can tune the electronic properties of the beta-SiC, and reduce the band gap of semiconductor catalyst beta-SiC from the value of 2.739eV-0.535eV. Which makes the beta-sic response to the wider UV-Vis spectrum, and transition metal atom (Cu, Co) tuned beta-sic can help to boost the photocatalytic quantum efficiency of photocatalytic AB hydrolysis reaction. In the process of CuCo/beta-SiC catalyzed AB hydrolysis, the reaction path can be described in three key steps: At first, CuCo/beta-SiC bond to B of AB, induce the B-H bond activation, then H3B- attacked by a H2O molecule, which contributes to the concerted dissociation of B-N bond. Finally, via -BH3 hydrolysis and produce the borate ion accompanied by the H-2 produce. In the reaction of AB hydrolysis, the reaction barrier step is the step of H2O molecule attack -BH3, and its energy barrier is 31.44 kcal/mol. In addition, the synergistic hydrolyze and photolyze AB to H-2 evolution mechanism was first proposed due to AB can be photocatalyzed by semiconductor photocatalyst beta-SiC and conventional catalyzed by the metal catalyst. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.