Semiconductor Photocatalyst Preparation And Decomposition Of Hydrogen Sulfide

ZnO/ZnS composite photocatalyst and series CdxZn1-xS solid solution composite photocatalysts were prepared, the crystal structure and photo-physical property were characterized by XRD, UV-Vis diffuse reflection spectra, TPR, TG, SEM-EDS, SPS, and the performance of these photocatalysts for photocatalytic decomposition of H2S to produce H2 was investigated. ZnO/ZnS composite photocatalyst prepared by precipitation was composed of cubic ZnS particles and hexagonal ZnO particles, which would restrain the recombination of the photo electrons and holes according to the coupling effect of two semiconductors, and extend the absorption of light. The photoefficiency of ZnO/ZnS photocatalyst improved compared with pure ZnS or ZnO photocatalysts. The series CdxZn1-xS solid solution composite photocatalysts prepared by coprecipitation are hexagonal structure. The band gap energy decreased successively from 3.52 to 2.54 with the change of x value from 0.1 to 0.9 in CdxZn1-xS, which could control the band structure of semiconductors. The results for H2 production from photodecomposition of H2S showed the highest H2 evolution rate could reach 7.61mmol/g·h over Cd0.7Zn0.3S photocatalyst calcined under N2 atmosphere at 650℃。The influence of the mass of photocatalyst, the concentration of reaction solution and the radiant flux on the H2 evolution rate over Cd0.7Zn0.3S photocatalyst was also investigated. The highest H2 evolution rate occurred in 2.0 mol/L NaOH solution saturated by H2S, which could reach 11.1 mmol/g·h. The optimum mass of photocatalyst was 0.20 g. The relationship between H2 evolution rate and radiant flux was close to r∝Φ12 through polynomial fitting.