Enhanced photocatalytic 3D/2D architecture for CO2 reduction over cuprous oxide octahedrons supported on hexagonal phase tungsten oxide nanoflakes

The 3D/2D architecture of Cu2O octahedrons/WO3 nanoflake were built on the substrate surface of fluorine-doped stannic oxide. The composite photocatalyst was composed by Cubic phase Cu2O/hexagonal phase WO3. The photoreduction CO2 activities of the composite samples were studied in the presence of water vapor. The yields and selection of CO and CH4 products were changed with deposited Cu2O. With the present of Cu2O octahedrons on the WO3 flake, the CH4 product appeared and the maximal CO and CH4 yields could attain 7.04 and 8.42 μmol after 24 h of visible-light irradiation. The photostability and photoactivity of Cu2O for CO2 reduction were enhanced by the building of the WO3/Cu2O heterojuntion. The Type II band alignment for WO3/Cu2O heterojuntion was characterized by UV–Vis reflectance and value-band X-Ray photoelectron spectroscopy and the Z-scheme mechanism of photoinduced electron-hole was further proposed. This study could offer a new clue for designing Cu2O-based heterojunction photocatalysts for CO2 reduction. [Display omitted] •3D/2D architecture catalyst of Cu2O octahedron and WO3 flake was synthesized.•The photoreduction of CO2 to CH4 was realized by Cu2O/WO3 photocatalyst.•The photostability of Cu2O was enhanced by the Z-scheme heterojunction.•The Cu2O/WO3 presented the good stability for 4 cyclings.