Ultra-fast construction of CuBi2O4 films supported Bi2O3 with dominant (0 2 0) facets for efficient CO2 photoreduction in water vapor

CuBi2O4/Bi2O3 thin film was synthesized on the commercial glass by a spray pyrolysis-calcination method. The monoclinic phase Bi2O3 with dominant (0 2 0) facets was grown on the surface of tetragonal phase CuBi2O4 by the temperature control of spraying process. Photocatalytic activities of the synthesized materials for CO2 reduction were measured in the presence of water vapor under visible light irradiation (λ > 400 nm). The CO, CH4 and O2 yields of the optimal composite film reached 247.62, 119.27 and 418.00 μmol/m2 after 12 h of irradiation. The composite film resisted physical damage and showed good photocatalytic activity in the cycling tests. Moreover, it was found that the types of main products changed with the light intensity and their yields varied with the light wavelength. The exposed (0 2 0) facets efficiently improved the adsorbed ability for H2O molecules. Meanwhile, the hydrophobicity of the film surface ensured that the adsorbed sites of CO2 were unoccupied by abundant H2O molecules. The S-scheme charge transfer mechanism was further confirmed by the interlaced band alignment of the CuBi2O4/Bi2O3 heterostructure and the controlled experiment with different light conditions. The results gained in this report may open up an avenue to design advanced S-scheme heterostructures with suitable transitional-metal oxides for photoreduction CO2 to solar fuels.