Photocatalyst In The Visible Light Photocatalytic Reduction Of Carbon Dioxide

In this paper, CdxZn1-xS solid solution composite photocatalysts was prepared by coprecipitation, CdS/TiO2composite catalysts and a series of nonmetal doping CdS/n-TiO2(n=C, N, S) catalysts were prepared by hydrothermal method. The above-prepared photocatalysts had been used for the photocatalytic reduction of carbon dioxide in the UV and visible light independently to experiment investigate their catalytic properties, and characterized to analyses their structure and photochemical properties by XRD, UV-Vis, SPS, XPS, SEM analysis media.The CdxZn1-xS solid solution composite photocatalysts prepared by coprecipitation are hexagonal structure. The band gap energy gradually reduce with the increase of x value, to control the energy level structure of semiconductors. The effect of calcination temperature on the properties and performance of catalyst was also examined. It was showed for photocatalytic reduction of carbon dioxide that Cdo.7Zno.3S cacalcinated at550℃under the protection of N2exhibited the best formic acid yield of360.12μmol/(h·g) under UV light and of35.34μmol/(h-g) under visible light.CdS/TiO2composite catalysts had been prepared by hydrothermal method and the effect of molar ratio of CdS/TiO2and hydrothermal temperature on the structure and properties had been investigated. The result showed that CdS/TiO2with R=1/2, T=200℃exhibited the best formic acid yield of185.7μol/(h·g) under UV light, no acid yield under visible light. The composite structure effectively prevents electron-hole from recombination, and extends its photoresponse range, which enhances the photocatalytic production rate.CdS/n-TiO2(n=C, N, S) composite photocatalysts had been prepared by hydrothermal method. n-TiO2(n=C, N, S) was obtained by immersion and calcinations method, using thiourea (TU), citric acid (CA) and urea (UA) as dopant material independently. The results of analysis showed that doping non-metallic elements not changed the catalyst crystal type, improved the charge separation efficiency and led to a red shift of TiO2absorption edge for significant improvement of catalytic performance. The results of photocatalytic reduction of carbon dioxide show that CdS/S, N-TiO2as photocatalyst, the yield of formic acid under UV light was500.07μmol/(h·g), under visible light was107.35μmol/(h-g); CdS/C-TiO2as photocatalyst, the yield of formic acid under UV light was515.56μmol/(h·g), under visible light was115.67μmol/(h·g); CdS/N-TiO2as photocatalyst, the yield of formic acid under UV light was531.71μmol/(h-g), under visible light was119.48μmol/(h·g). The yield of CdS/n-TiO2(n=N, S, C) was higher than that of the undoped modifi CdS/TiO2.