Photoelectrocatalytic Reduction of CO 2 to Chemicals via ZnO@Nickel Foam: Controlling C–C Coupling by Ligand or Morphology

The CO2 reduction is a very attracting research field in the environmental, material and chemical sciences in light of the energy crisis and greenhouse effect. A new photoelectrocatalytic system composed of a photoanode BiVO4 and a photocathode of nickel foam supported ZnO semiconductor was designed, assembled and applied to CO2 reduction in water. The photocathodes with different morphology could be made from electrochemical deposition method and well characterized by SEM, UV–Vis, XRD, and XPS. The photoelectrocatalytic cell of ZnO/Ni-30|KHCO3|BiVO4 can produce ethanol and acetic acid in a rate of 12.5 µM h−1 cm−2 with 100% selectivity for C2 product, attributing to the controlling of 3D-spaces of nanorod. The cell of A-ZnO/Ni-15|KHCO3|BiVO4 produces ethanol and acetic acid with 75% selectivity for C2 product under 100 mW cm−2 simulated sunlight irradiation, attributing to controlling of both amine ligand and morphology of ZnO, which reveal a new way to increase the selectivity of products.