InVO₄/β-AgVO₃ Nanocomposite as a Direct Z-Scheme Photocatalyst toward Efficient and Selective Visible-Light-Driven CO₂ Reduction

Abstract

Photocatalytic CO₂ reduction to solar fuel is a promising route to alleviate the ever-growing energy crisis and global warming. Herein, to enhance photoconversion efficiency of CO₂ reduction, a series of direct Z-scheme composites consisting of β-AgVO₃ nanoribbons and InVO₄ nanoparticles (InVO₄/β-AgVO₃) are prepared via a facile hydrothermal method and subsequent in situ growth process. The prepared InVO₄/β-AgVO₃ composites exhibit enhanced photocatalytic activity for reduction of CO₂ to CO under visible-light illumination. A CO evolution rate of 12.61 μmol·g^-1·h^-1 is achieved over the optimized 20% In-Ag without any cocatalyst or sacrificial agent, which is 11 times larger than that yielded by pure InVO₄ (1.12 μmol·g^-1·h^-1). Moreover, the CO selectivity is more than 93% over H₂ production from the side reaction of H₂O reduction. Significantly, based on the results of electron spin resonance (ESR) and in situ irradiated XPS tests, it is proposed that the synthesized InVO₄/β-AgVO₃ catalysts comply with the direct Z-scheme transfer mechanism. Significantly improved photocatalytic activities for selective CO₂ reduction could be primarily ascribed to effective separation of photoinduced electron-hole pairs and enhanced reducibility of photoelectrons at the conduction band of InVO₄. This work provides a new insight for constructing highly efficient photocatalytic CO₂ reduction systems toward solar fuel generation.