Preparation of WO3/In2O3 heterojunctions and their performance on the CO2 photocatalytic conversion in a continuous flow reactor

This study investigated the CO2 conversion in the gas phase using the WO3/In2O3 photocatalysts synthesized by the solvothermal method at different WO3 content (5, 10, and 15 wt%). The experimental results in a continuous flow reactor demonstrated that carbon monoxide was the main product obtained from the photocatalytic reduction of CO2 using the coupled oxides and the individual semiconductors. However, in addition to CO, the WO3/In2O3 catalyst also produced CH4 and C3H6 hydrocarbons. The incorporation of WO3 into In2O3 inhibits the crystal growth and changes the preferentially formed cubic phase of In2O3 to the hexagonal phase structure, promoting the generation of hydrocarbons. The W15%/In coupled catalyst exhibited the best performance on methane and propylene production. This behavior was attributed to the enhanced interaction between the gas and the catalyst surface, and the improved charge separation promoted by the direct Z-scheme mechanism in the W15%/In heterojunction.