Regulating the band structure by modifying Ti3C2 and doping Fe ions improved photocatalytic activity and selectivity of ZnGa2O4–Ti3C2–Fe for photoreducted CO2 into CH4

Abstract

Novel Ti3C2-modified and Fe-doped ZnGa2O4 (ZnGa2O4–Ti3C2–Fe) are designed and prepared by hydrothermal method according to the mechanism of photoreducted CO2 into CO and CH4. ZnGa2O4–Ti3C2–Fe exhibits higher photocatalytic activity and selectivity to produce CH4 for photoreducted CO2 compared with ZnGa2O4. Based on the characterizations of X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and ultraviolet–visible (UV–vis) absorption, it is shown that the modification of Ti3C2 surface species or/and doping of Fe3+ ions can regulate the band structure of ZnGa2O4 and its matching relationship with redox potential on photoreducted CO2, and improve the absorption of visible light and the separation of photogenerated charge carriers, leading to the enhancement of photocatalytic activity and selectivity to product CO and CH4 on photoreduction CO2. Especially, the synergistic effect of Ti3C2 and Fe3+ ions realizes the conversion of CO2 to CO and then from CO to CH4, thus significantly improving the photocatalytic activity of ZnGa2O4–Ti3C2–Fe for photoreducted CO2 to CH4. These results provide a paradigm for the design and fabrication of a novel photocatalyst, which has excellent photocatalytic performance and outstanding selectivity for photoreducted CO2 into CO and CH4.