Preparation method of composite photocatalyst CdS/n-TiO2 for catalyzing and decomposing H2S to prepare hydrogen

The invention provides a preparation method of a composite photocatalyst CdS/n-TiO2 for catalyzing and decomposing H2S to prepare hydrogen and relates to a preparation method of a composite photocatalyst. The preparation method solves the problem of low hydrogen generation rate when H2S is optically catalyzed and decomposed by CdS/TiO2. The preparation method comprises the following steps: ultrasonically dispersing, drying, grinding and roasting nanometer TiO2 in a dispersing agent to obtain n-TiO2; adding the n-TiO2 in a cadmium salt solution and a vulcanizing agent solution to obtain yellow gelatinous precipitates; and obtaining the composite photocatalyst CdS/n-TiO2 by hydrothermally processing, cooling, washing and filtering the precipitates and drying filter residues. Compared with the CdS/TiO2 photocatalyst, the composite photocatalyst obtained by the preparation method increases the hydrogen generation rate by 28 percent to 52 percent under visible light.