Transition metal tuned semiconductor photocatalyst CuCo/β-SiC catalyze hydrolysis of ammonia borane to hydrogen evolution

Abstract

In the study, a novel approach of Cu, Co tuned photocatalyst β-SiC catalyze hydrolysis of ammonia borane was proposed as a means to boost H2 evolution. Electronic properties including band structure and DOS of β-SiC and CuCo/β-SiC are calculated. In addition, the hydrolysis mechanism of AB and photocatalytic boosting mechanism of AB hydrolysis on the catalyst CuCo/β-SiC are discussed. The systematic investigation showed that the transition metal atom (Cu, Co) can tune the electronic properties of the β-SiC, and reduce the band gap of semiconductor catalyst β-SiC from the value of 2.739eV–0.535eV. Which makes the β-SiC response to the wider UV–Vis spectrum, and transition metal atom (Cu, Co) tuned β-SiC can help to boost the photocatalytic quantum efficiency of photocatalytic AB hydrolysis reaction. In the process of CuCo/β-SiC catalyzed AB hydrolysis, the reaction path can be described in three key steps: At first, CuCo/β-SiC bond to B of AB, induce the BH bond activation, then H3B- attacked by a H2O molecule, which contributes to the concerted dissociation of BN bond. Finally, via BH3 hydrolysis and produce the borate ion accompanied by the H2 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 H2 evolution mechanism was first proposed due to AB can be photocatalyzed by semiconductor photocatalyst β-SiC and conventional catalyzed by the metal catalyst.