Synthesis of Zn0.4(CuGa)0.3Ga2S4/CdS Photocatalyst for CO2 Reduction

Abstract

Conversion of CO2 into fuels by photocatalysis is promising in solving the energy crisis and the greenhouse effect. Among various photocatalytic materials, Zn1-2x(CuGa)xGa2S4 materials possess visible light response and high conduction band potential, which are ideal CO2 reduction materials from thermodynamics aspect. However, their photocatalytic CO2 reduction activity is still low which is urgent to improve its activity in terms of kinetics. In this study, Zn0.4(CuGa)0.3Ga2S4 was synthesized and composited with CdS nanoparticles with different proportions to form Zn0.4(CuGa)0.3Ga2S4/CdS heterojunction photocatalysts. A series of characterizations suggest that CdS is uniformly grown on surface of Zn0.4(CuGa)0.3Ga2S4 microcrystals to form Z-scheme type all-solid heterojunction composite materials. Such a structure effectively suppresses the recombination of electron-hole pairs and improves the photocatalytic performance. In the solution CO2 reduction system, the as-prepared Zn0.4(CuGa)0.3Ga2S4/CdS can effectively reduce CO2 into CO under visible light irradiation. The optimal molar ratio of Zn0.4(CuGa)0.3Ga2S4 and CdS in composite materials is 2 : 1, whose photocatalytic performance is 1.7 times of that of Zn0.4(CuGa)0.3Ga2S4/ CdS and 1.6 times of that of CdS. This work constructs all solid Z-scheme type Zn0.4(CuGa)0.3Ga2S4/CdS heterojunction materials with enhanced photocatalytic activity for CO2 reduction, which is promising for designing novel photocatalysts in the field of artificial photosynthesis.