Tailoring the oxidation state of metallic TiO through Ti3+/Ti2+ regulation for photocatalytic conversion of CO2 to C2H6

The regulation and stabilization of the oxidation state to promote the conversion of CO 2 to C 2 fuel still faces many challenges. Based on the principle of charge balance, we creatively propose a co-doping strategy to adjust the surface oxidation state distribution of metallic catalysts . A TiO-based photocatalyst co-doped with Zn and N was synthesized by ammonia assisted one-step calcination method, named ZN-TC. XPS characterization shows that Zn and N adjust the valence states of adjacent Ti elements respectively, so that the surface of TiO maintains a relatively stable Ti 3+ /Ti 2+ ratio. Under visible light irradiation, the material can catalyze CO 2 into CO (324.11 μmol·g −1 ·h −1 ) and C 2 H 6 (10.27 μmol·g −1 ·h −1 ) in the liquid phase . The selectivity of C 2 H 6 reached 14.45%. When irradiated with near-infrared light, ZN-TC shows 100% CO selectivity because the photon energy is not enough to support the catalytic hydrogenation of CO 2 . Theoretical calculations and experiments proved that Zn and N elements mainly act on the B -1 band to regulate the Ti valence state. In-situ DRIFTS and in-situ Raman tests confirmed the function of oxidation state adjustment to promote the C-C coupling on the catalyst surface to produce ethoxy groups , which ultimately led to the production of C 2 H 6 .