Direct Z-scheme charge transfer of Bi₂WO₆/InVO₄ interface for efficient photocatalytic CO₂ reduction

InVO₄ possesses great potential in photocatalytic CO₂ conversion. It is still highly desired to develop efficient strategies of photocatalyst fabrication to prevent its attenuated activity caused by the rapid recombination of photogenerated electron-hole. Herein, a direct Z-scheme heterojunction of Bi₂WO₆/InVO₄ nanosheets is constructed via two-step hydrothermal synthesis. The Bi₂WO₆/InVO₄ composite exhibits a superior photocatalytic performance toward CO₂ reduction into CO and CH₄ under visible light irradiation. The CO evolution rate reaches up to 17.97 μmol g⁻¹ h⁻¹, while the CH₄ production rate is 1.13 μmol g⁻¹ h⁻¹, which are higher than those catalyzed by bare InVO₄ and bare Bi₂WO₆. Based on the photoelectrochemical results, hydroxyl radical test, Scanning Kelvin Probe (SKP) and electron spin resonance (ESR) investigation, the enhanced activity of CO₂ reduction can be attributed to a Z-scheme electron transfer at the interface to promote spatial charge separation, which effectively preserves the reduction ability of photoelectron on the conduction band of InVO₄ for CO₂ conversion.