B-TiO2/CuInS2 photocatalyst based on the synergistic effect of oxygen vacancy and Z-scheme heterojunction for improving photocatalyst CO2 reduction

Photocatalytic reduction CO2 into valuable solar fuels is a promising strategy to alleviate the greenhouse effect and the energy crisis on Earth. In this work, a B-TiO2/CuInS2 photocatalyst has been synthesized through a simple hydrothermal-calcination method for efficient reducing CO2 into CO and CH4. Boron doping and sensitization of CuInS2 ensure the excellent visible light response capacity of the composite catalyst. The synergistic effect between oxygen vacancies and Z-scheme heterojunction also endow the photocatalyst with strong carrier separation capability. Consequently, the optimized B-TO/CIS-2.5 sample exhibited the best CO (21.39 μmol g−1 h−1) and CH4 (4.83 μmol g−1 h−1) production, approximately 9 and 14 times higher than that of TO and B-TO, respectively. This study provides a reliable approach for developing photocatalysts with boosted CO2 reduction activity and high stability.