Nanoarchitectronics\nfor Photocatalytic CO<sub>2</sub> Reduction:\nUnveiling Interfacial Charge Transfer Excitons in the\nKFeO<sub>2</sub>–BiVO<sub>4</sub> Composite

In this study, a\nseries of KFeO<sub>2</sub>–BiVO<sub>4</sub> nanocomposites\nwith different KFeO<sub>2</sub> contents have been\nprepared by a simple hydrothermal method and used as photocatalyst\nin the photocatalytic reduction of CO<sub>2</sub> with H<sub>2</sub>O to methane (CH<sub>4</sub>) and carbon monoxide (CO) under visible\nlight irradiation. The as-synthesized KFeO<sub>2</sub>–BiVO<sub>4</sub> nanocomposites have been characterized using an X-ray diffractometer\n(XRD), a scanning electron microscope (SEM), an attenuated total reflection\nFourier transform infrared spectrometer (ATR-FTIR), an ultraviolet–visible\nlight spectrometer (UV–vis), and a photoluminescence spectrometer\n(PL). In the photocatalytic CO<sub>2</sub> reduction experiments,\nKFeO<sub>2</sub>–BiVO<sub>4</sub> (1:1) exhibited an improvement\nof photocatalytic activity for the CO<sub>2</sub> photoreduction due\nto the reduced electron–hole pair recombination and increased\nBET specific area. When irradiated with a blue light lamp, the cumulative\nCO yield for KFeO<sub>2</sub>–BiVO<sub>4</sub> (1:1) reached\nabout 54.6 μmol g<sup>–1</sup> (the quantum yield was\n0.14%) and the cumulative yield of CH<sub>4</sub> was 34.1 (the quantum\nyield was 0.35%). Based on the experimental results, a plausible photocatalytic\nreaction mechanism for photoreduction of CO<sub>2</sub> has been proposed\nin this study. In addition, the charge enhancement photoreduction\nproperties of KFeO<sub>2</sub>–BiVO<sub>4</sub> have been verified\nby DFT calculations