Black single-crystal TiO2 nanosheet array films with oxygen vacancy on {001} facets for boosting photocatalytic CO2 reduction

Black TiO2 nanosheet array films with oxygen vacancy on {001} facets were prepared by solid phase reaction with a mild aluminothermic reduction method. The oxygen vacancies increase the absorption of visible light and the separation efficiency of photogenerated electron-hole pairs. For the black TiO2 with oxygen vacancy prepared by annealing, only the oxygen vacancies on {001} facets boost the photocatalytic CO2 reduction, while these on {101} facets in a small number increase the recombination of photogenerated electrons and holes and inhibit the photocatalytic CO2 reduction performance. Meanwhile, the black TiO2 nanosheet array films with oxygen vacancy on {001} facets have a good photocatalytic CO2 reduction to CO with a reduction rate of 128.5 mu mol.g(-1).h(-1) under visible light irradiation, which is ascribed to the formation of oxygen vacancy and the synergistic effect of special unsaturated coordination Ti-5c atom improving the adsorption capacity of CO2 and increasing the reduction rate of CO2 to CO. (C) 2021 Elsevier B.V. All rights reserved.