Photocatalytic Reduction of CO2 over CdxZn1-xS Photocatalysts

A series of CdxZn1-xS (x=0.1 similar to 0.9) composite photocatalysts were prepared by coprecipitation method. The above-prepared photocatalysts were characterized by X-ray diffraction (XRD), UV-Vis diffusive reflectance spectroscopy (DRS),surface photovoltage spectroscopy (SPS). It was shown from XRD that CdxZn1-xS solid solution semiconductors were of hexagonal phase in agreement with pure CdS. The DRS and SPS results showed that the band gap energy gradually reduced with the increasing of x value in CdxZn1-xS, and when x = 0.7, the Cd0.3Zn0.3S photocatalyst had the strongest surface photovoltage. It was found from photocatalytic reduction of CO2 that the highest HCOOH production rate of 342.64 mu mol/(g.h) over Cd0.7Zn0.3S photocatalyst among a series of CdxZn1-xS photocatalysts were obtained under 250 W high pressure mercury lamp.