The Research Of Mo₂N Cocatalyst In Photocatalytic H₂ Evolution

Mo2N has been proved to be a kind of cocatalyst in the photocatalysis. Generally, cocatalyst particle sizes, kinds and structure of surface atom can influence the species and quantity of active center and surface area of cocatalyst. Those are the main reasons leading to the different photocatalytic efficiency. So, we need to prepare the cocatalyst with high surface area, more active sites and selectivity for products with high active crystal face through the refined synthetic methods. Cocatalysts will largely enhance the rate of photocatalytic reaction.This paper mainly synthesized Mo2N non-noble mental cocatalysts with the different morphology.(1) The preparation methods of hexagonal rods Mo2N and performance of photocatalytic H2 evolution were studied. The photocatalytic hydrogen production of h-Mo2N/CdS is 218p mol/h,which is 2.0 times of irregular-Mo2N/ CdS and 10.0 times of CdS alone. The photocatalytic hydrogen activity of h-Mo2N/CdS is obviously higher than that of the Au, Ru, Pt and Pd loaded CdS, however, lower than the Rh/CdS.(2) The photoelectrochemical properties of hexagonal were researched. The capacitance of h-Mo2N is bigger than that of irregular Mo2N. h-Mo2N/CdS has a lower resistance than that of the CdS under the visible light irradiation. This work demonstrates the existence of h-Mo2N can facilitate the separation of photo-induced charges of CdS. The intensity of transient photocurrent responses of h-Mo2N/CdS is the highest and that the CdS is the weakest. These show that the separation of photo-induced charges and holes was promoted after the h-Mo2N loaded with CdS.The discharge velocity of h-Mo2N/CdS is slower than that of irregular-Mo2N/CdS, Pt/CdS and CdS alone. These demonstrate that the non-noble mental coatalyst Mo2N has a capacity to reserve the photo-induced electron. So, it can retard the recombination of photo-induced charges and holes,consequently, this will be enhanced the activity of photocatalysts and prolonged its stability.(3) The preparation of microbelt Mo2N and its photo(electrochemical) properties were researched. The microbelt Mo2N alone has no photocatalytic activity. The photocatalytic hydrogen production of microbelt Mo2N/CdS is 66?mol/h,which is 2.0 times of sphere-Mo2N/CdS, 2.7 times of CdS alone and 3.0 times of Au/CdS. The photoelectrochemical properties have proved that the capacitance of microbelt-Mo2N is bigger than that of sphere-Mo2N. Microbelt-Mo2N has a lower resistance than that of sphere-Mo2N and be beneficial to the photocatalytic reaction under the visible light irradiation.(4) The preparation of Pt/Mo2N and its photo(electrochemical) properties were researched.The photocatalytic hydrogen production of Pt/Mo2N/CdS is 173? mol/h, which is 2.0 times of irregular-Mo2N/CdS and 7.2 times of CdS alone. The photoelectrochemical properties have proved that the capacitance of Pt/Mo2N is the biggest. The intensity of transient photocurrent responses of Pt/Mo2N/CdS is the highest. This work demonstrates that the Pt/Mo2N can accelerate the separation of photo-induced electrons and holes, and facilitate the photocatalytic reaction.