Facile fabrication of CdIn2S4/TiO2 heterojunction for enhanced solar light efficient CO2 reduction

Photocatalytic CO₂ reduction is a promising solution to simultaneously provide renewable chemical fuels and address the greenhouse effect. However, designing practical photocatalysts with advanced architectures remains challenging. Herein, we report the preparation of a novel CdIn₂S₄/TiO₂ binary heterojunction via an in situ solvothermal approach, which exhibits superior photocatalytic activity for sunlight-driven CO₂ reduction. The CdIn₂S₄/TiO₂ composites exhibit significantly enhanced photocatalytic performance for CO₂ reduction compared to unmodified TiO₂. Among them, the 3% CdIn₂S₄/TiO₂ composite has optimal CO and CH₄ evolution rates of 18.32 and 1.03 µmol·g⁻¹·h⁻¹, respectively. The yield of CO is 4.7 times higher than that of pristine TiO₂. This improved photocatalytic activity of the CdIn₂S₄/TiO₂ heterostructure can be attributed to its large surface area, extended light absorption range and high separation efficiency of photogenerated electron-hole pairs, which are supported by the results of photoluminescence spectroscopy and the photoelectrochemical measurements. Moreover, the photocatalytic mechanism based on the binary CdIn₂S₄/TiO₂ heterojunction is proposed and separation process of photogenerated electron-hole pairs is discussed. In brief, we aim to provide insights into the application of TiO₂ in energy conversion processes through the construction of heterogeneous junctions.