Nanoarchitectronics for Photocatalytic CO2 Reduction: Unveiling Interfacial Charge Transfer Excitons in the KFeO2–BiVO4 Composite

In this study, a series of KFeO₂–BiVO₄ nanocomposites with different KFeO₂ contents have been prepared by a simple hydrothermal method and used as photocatalyst in the photocatalytic reduction of CO₂ with H₂O to methane (CH₄) and carbon monoxide (CO) under visible light irradiation. The as-synthesized KFeO₂–BiVO₄ nanocomposites have been characterized using an X-ray diffractometer (XRD), a scanning electron microscope (SEM), an attenuated total reflection Fourier transform infrared spectrometer (ATR-FTIR), an ultraviolet–visible light spectrometer (UV–vis), and a photoluminescence spectrometer (PL). In the photocatalytic CO₂ reduction experiments, KFeO₂–BiVO₄ (1:1) exhibited an improvement of photocatalytic activity for the CO₂ photoreduction due to the reduced electron–hole pair recombination and increased BET specific area. When irradiated with a blue light lamp, the cumulative CO yield for KFeO₂–BiVO₄ (1:1) reached about 54.6 μmol g^–1 (the quantum yield was 0.14%) and the cumulative yield of CH₄ was 34.1 (the quantum yield was 0.35%). Based on the experimental results, a plausible photocatalytic reaction mechanism for photoreduction of CO₂ has been proposed in this study. In addition, the charge enhancement photoreduction properties of KFeO₂–BiVO₄ have been verified by DFT calculations