Abstract: Indium vanadate (InVO₄) possesses excellent potential in photocatalytic carbon dioxide (CO₂) reduction, but further modifications of reducing charge recombination and increasing active sites are still needed. Herein, InVO₄/g-C₃N₄ (InVO-CN) heterojunction composite photocatalysts were prepared via in situ formation of InVO₄ nanoparticles on the lamellar structure of graphite carbon nitride (g-C₃N₄) containing nitrogen (N) defects. Among these composites, 30% InVO-CN showed the best photoreduction performance for CO₂ at normal temperature and pressure without sacrificial agent (carbon monoxide, CO: 20.14 μmol g^-1 h^-1; methane, CH₄: 3.46 μmol g^-1 h^-1), which were 1.8 and 2.8 times higher than these of pure g-C₃N₄ and InVO₄. The excellent performance could be attributed to the enhancement of CO₂ adsorption, and most importantly, the enhanced charge carrier separation and reduction capacity induced by the formation of Z-scheme heterojunction between InVO₄ and g-C₃N₄. In this work, intimate heterojunction interfaces between materials were formed by introducing g-C₃N₄ with defects in InVO₄, which provides a promising modification scheme.

Key words: Z-scheme heterojunction, CO₂ photoreduction, g-C₃N₄,InVO₄