Controllable synthesis of Cu2O decorated WO3 nanosheets with dominant (0 0 1) facets for photocatalytic CO2 reduction under visible-light irradiation

Systematical design and controllable assembly of nanostructured photocatalysts have received much attention in the field of CO2 reduction. The Cu2O decroted hexagonal WO3 nanosheets with and without dominant (0 0 1) facets (Cu2O/WO3-001 and Cu2O/WO3) were synthesized vertically on the surface of fluorine-doped stannic oxide (FTO) substrate and their photocatalytic performance for CO2 reduction were evaluated in the presence of H2O vapour under visible light irradiation (λ > 400 nm). The Cu2O/WO3-001 catalyst exhibited higher photocatalytic activity than those of Cu2O, WO3-001 and Cu2O/WO3. The maximal product yields of CO, O2 and H2 for Cu2O/WO3-001 after 24 h illumination reached 11.7, 5.7 and 0.7 μmol, respectively, and good cycling ability was discovered after 4 cycles. The (0 0 1) facet of hexagonal phase WO3 nanosheet was in favor of the H2O oxidation in the CO2 reduction process. Additionally, the Z-scheme charge transfer mode of Cu2O/WO3 heterojunction could promote photoinduced charge separation and enhance redox ability of the separated electrons and holes, leading to excellent photocatalytic CO2 reduction performance. The study may provide some insights into the coherent design of specific nanosheet photocatalysts with Z-scheme charge transfer for CO2 reduction.