Visible Light Hydrogen Production By CdZnS Photocatalysts Prepared in Ethylenediamine Aqueous Solution

摘要

Recently, semiconductor photocatalysts are expected to be a strategy to solve the energy demand and environmental pollution. Many researchers have attention, and have been developed photocatalysts for hydrogen production. Among them, metal sulfides (i.e. CdS, ZnS, MoS_2, etc.), metal oxides (i.e. TiO_2, Fe_2O_3, NiO_x, RuO_2) are regarded as good candidates for the photocatalytic H_2 production. CdS is highly important as a photocatalyst because of the low band gap energy (～2.4 eV) and high activity under visible light irradiation for the photocatalytic hydrogen evolution reaction (HER). However, pure CdS tends to form particle aggregation and inherent photocorrosion, resulting in a higher recombination rate of charge carrier limited its application. One of the effective ways is by combing CdS with ZnS to form CdZnS (cadmium zinc sulfide). CdZnS has been regarded as a promising photocatalyst, but it has fast recombination of photogenerated electron-hole pairs. Therefore, the photocatalytic hydrogen evolution activity of sulfide semiconductor can be significantly improved by loading noble metals as cocatalysts to provide active sites for proton reduction.