Oxygen vacancy-regulated metallic semiconductor MoO2 nanobelt photoelectron and hot electron self-coupling for photocatalytic CO2 reduction in pure water

This communication describes metallic MoO2−x nanobelts intrinsic photocatalytic CO2 reduction performance in pure water. The intrinsic wide-bandgap endowed MoO2 nanobelts great potential for CO2 reduction in ultraviolet, while localized surface plasmonic resonance (LSPR) and the metallic feature induced by oxygen vacancies ensured energetic electrons transform and fast kinetic transfer. Credit to the unique degenerate doping properties of MoO2−x nanobelts, the absorbed wavelength of intrinsic semiconductor bandgap overlapped with the LSPR absorption. Therefore, the high performance was ascribed to the self-coupling of intrinsic excited photoelectrons and plasmonic hot electrons. The surface abundant oxygen vacancies also facilitated preferable adsorption of CO2 and hence promoted the chemical activation. The according intrinsic CO production rate was 62.75 µmol/g/h in pure water under ultraviolet light, which was 6 times higher than that of commercial P25 photocatalyst (11.13 µmol/g/h). Our findings provide new insights and inspirations for parsing the mechanism and developing new-type MoO2-based photocatalysts.