| CdS is one of the most promising photocatalyst under the visible light for H2 production from water splitting due to its suitable band gap. However, only when CdS be loaded with Pt, Pd, Ir or other noble metals, it could show significant photocatalytic activity for H2 production from water splitting. Considering the scarcity and high price of noble metals, to develop a new preparation route to pursue a high photocatalytic performance and to minimize the use of costly noble metals, or to develop an alternative of non-noble metal catalysts is imminent. Based on this, this study focuses on the two aspects:in the study(1), for the first time, we prepared platinized CdS nanorods(Pt/CdS-N) by a simple and convenient one-pot solvothermal(OPS) method. The formation of hexagonal1 D structure CdS and the deposition of Pt(0) can be achieved simultaneously by the method, which is more convenient and efficient than the conventional post-deposition routes such as photochemical reduction and impregnation-reduction methods to enhance the photocatalytic activity of CdS-N for H2 evolution reaction(HER). The H2 evolution rate(rH2) of CdS-N could be remarkably improved from 2.10 to 10.29 mmol?h-1?g-1 by loading with only 0.06% Pt(wt. %) under visible light irradiation(λ>400 nm, 300 W Xe lamp). This loading amount of Pt is substantially lower than the reported optimal values(commonly in the range of 0.5-2%). A criterion of enhancement coefficient was proposed to identify the ideal loading amount of Pt and find this ultra-low amount 0.06 %(wt. %)of Pt is more practical than the optimal amount(determined to be 0.5%), considering the improvement efficiency of r H2 and the loading amount of Pt. According to a series of characterization results, the high and stable activity of Pt/CdS-N can be attributed to the hexagonal 1D structure of CdS and the high dispersion of Pt in the Pt(0) state. Besides Pt,the OPS method is also valid for the deposition of Pd or Ru on CdS and r H2 decreases in order Ru/CdS-N(12.89)>Pt/CdS-N(10.29)>Pd/CdS-N(6.72 mmol?h-1?g-1) at the nominal loading amount of 0.06%. It reveals that the using of noble metal co-catalyst can be significantly reduced without unduly sacrificing the HRE efficiency. The developed OPS route provides a new insight into the preparation of highly efficient and stablechalcogenide photocatalysts for HER. On the other hand, in the study(2), we mainly study the synthesis of non-noble metal MoS2 cocatalyst by in situ route and its effect on CdS-N for hydrogen production activity, to explore the possibility of Mo S2 instead of precious metals. In this part of our study, we take the sulfur ammonium molybdate as a precursor,MoS2 be deposited on the surface of CdS nanorods through a simple in-situ photoreduction method. The H2 evolution rate(rH2) of CdS-N could be remarkably improved from 2.54 to8.08mmol?h-1?g-1 by loading with only 0.2%(wt. %) Mo S2. The method is more efficient than the chemical reduction and the impregnation reduction methods. The closely interfacial contact of Mo S2 and CdS-N is very important factor responsible for the enhanced charge separation efficiency and better utilization of visible light, were crucial to the improved photocatalytic activity. |
PDF Full Text Request