Novel method of high-efficient synergistic catalyze ammonia borane hydrolysis to hydrogen evolution and catalytic mechanism investigation

摘要

In the study, we have successfully prepared beta-SiC NWs, Pt-Ru/beta-SiC NWs as the high-efficient catalysts to synergistic catalytic AB hydrolysis to hydrogen evolution. In addition, the mechanism of the Pt-Ru nanoclusters modified the band structure of the beta-SiC NWs and the synergistic catalytic AB hydrolysis are addressed clearly, and proposed a newly possible mechanism of photocatalytic AB hydrolysis to produce hydrogen. The orbital hybridizations of Pt-3d-orbitals, 4s-orbitals and Ru-3d-orbitals, 4s-orbitals, 4p-orbitals to the beta-SiC result in the variation of band structure and band gap, the experiment results show the band gap of beta-SiC NWs, Pt/beta-SiC NWs and Ru/beta-SiC NWs are 2.36 eV, 1.97 eV and 1.74 eV, respectively. Pt-Ru nanocluster's modification is beneficial to increase the transition probability of photo-induced electrons and the separation of photo-electron and hole pairs, and then improve the photocatalytic quantum efficiency. Pt-Ru/beta-SiC NWs both obtained higher catalytic activity in the light irradiation condition compare with in dark condition, the reaction required time decreased by 2'26. and 4. 12'. The experimental results above confirm the synergistic photocatalytic AB hydrolysis and conventional metal catalyze AB hydrolysis exist in the Pt-Ru/beta-SiC NWs catalytic AB hydrolysis reaction system. Ru/beta-SiC NWs have a perfect reusability due to the required time of completed reaction only extended by 0'58. even experiencing ten life cycles. In addition, the previous mechanism of AB photocatalytic hydrolysis which believes the reaction is related to the dissolved oxygen in the solution have proved to be inaccurate via demonstration experiment, and have proposed a newly possible mechanism of photocatalytic AB hydrolysis to produce hydrogen through the inference of the especial Lewis structure of AB.