Research On The Preparation Of Sulfide And Its Combinated Catalyst With TiO₂and Their Visible-Light Photocatalytic Performance

This paper mainly studies the combination between sulfide semiconductor and TiO2as well as preparation of Cd0.5Zn0.5S by KBr-assisted hydrothermal method. The activities of the as-preaered catalysts were evaluated by photocatalytic hydrogen production in the presence of Na2S-Na2SO3as electron donors. The reaction conditions are optimized to reach a highly efficient photocatalytic hydrogen production. The possible reaction mechanism is discussed. These works are divided into three parts:In the first part, the CdS-0.5%Pt/TiO2photocatalyst was prepared using hydrothermal method. We discussed the influences of the different molar ratio of CdS to TiO2, Pt loading content on the photocatalytic activity of the catalysts. XRD, UV-Vis, specific surface, SEM, electrochemistry and fluorescence were used to characterize the catalysts. When the molar ratio of CdS to TiO2is1:1, Pt loading content is0.5%, the catalyst has the highest photocatalytic activity. The presence of inorganic salts in seawater is benefit for electron donors trapping hydroxyl radical by electron donors. It promotes the effective separation of photoproduced electrons and holes, as well as the hydrogen production activity of the photocatalyst in sea water. The optimal conditions of the catalyst photocatalytic seawater splitting into hydrogen increased by33%compared with water splitting into hydrogen.The second part studies conbinatied catalysts of Cd0.5Zn0.5S and Pt/TiO2using hydrothermal method. The results showed that the combinatied catalyst photocatalytic activity greatly improved. When the molar ratioes of Cdo.5Zno.5S to TiO2and cadmium to zinc are5:10and1:1, resepectivly, the catalyst Cd0.5Zn0.5S-0.5%Pt/TiO2(5:10) exhibits a greatest degree of improvement in photocatalytic activity compared. Within illumination for30h, the Cd0.5Zn0.5S-0.5%Pt/Ti02(5:10) catalyst is stable for hydrogen production, and increased3.7times compared with single Cd0.5Zn0.5S. The cause for enhanced photocatalytic activity is the combination of Cd0.5Zn0.5S and Pt/TiO2can promote the effective separation of photoproduced electrons and holes. The third part studies Cd0.5Zn0.5S solid solution photocatalyst was prepared using KBr assisted hydrothermal method. We discussed the effect of KBr concentration on the activity of catalyst under visible light. The results show that the existence of KBr promotes the growth of ZnS (111) crystal facet in Cd0.5Zn0.5S solid solution and reduces nonradiative transition of the catalyst, thus the visible light photocatalytic activity of Cd0.5Zn0.5S is enhanced.