Z-Scheme Heterojunction CdIn2S4/BiVO4 with a Spherical Structure for Photocatalytic CO2 Reduction

Abstract

Z-scheme heterojunction photocatalysts are at the forefront of carbon dioxide reduction research. However, BiVO₄ faces challenges due to its inappropriate conduction band position and rapid charge carrier recombination. In this article, spherical CdIn₂S₄/BiVO₄ Z-scheme heterojunction composites attached to coiled nanosheets were synthesized via a hydrothermal method, which improved the CO₂ reduction efficiency and addressed these limitations. The morphology, crystal structure, band structure, and photoelectrochemical properties of the sample were further studied. The CdIn₂S₄/BiVO₄ composites exhibit superior photocatalytic activity compared to pure CdIn₂S₄ and BiVO₄, with the CdIn₂S₄/BiVO₄ composite containing 25% BiVO₄ yielding the highest CO and CH₄ production rates of 4.51 μmol g^–1 h^–1 and 1.01 μmol g^–1 h^–1, respectively, after 6 h and achieving an 81.7% CO selectivity. The Z-scheme design effectively mitigates charge recombination, boosts electron transfer, and enhances the photocatalytic CO₂ activity. The mechanism of photogenerated carrier transfer in catalysts was elucidated through density functional theory. This work offers insights and theories into the design and preparation of BiVO₄-based heterojunction photocatalysts.