Synergy of oxygen vacancy and piezoelectricity effect promotes the CO2 photoreduction by BaTiO3

Great efforts have been devoted to developing efficient visible-light-driven photocatalysts for the conversion CO2 into clean fuels. Nevertheless, the photoreduction of CO2 is hampered by inadequate surface-active sites and ineffective electron-hole pair separation. Herein, we explore the wheat-heading BaTiO3 with high surface area and piezoelectricity to facilitating their bulk charge separation. Meanwhile, oxygen vacancies were fabricated to extending the visible light absorption range and increasing the active sites of the wheat-heading BaTiO3, thus promoting the photocatalytic performance of CO2. Among the wheat-heading BaTiO3-X (X = 0, 0.5, 1.0, 1.5, 2.0) catalysts, BaTiO3-1.5 affords the optimal photocatalytic performance of CO, 6.41 μmol·g−1 under light, 9.17 μmol·g−1 under light and ultrasound, which were 3.22 and 1.86 times higher for pristine wheat-heading BaTiO3, respectively. This synergetic strategy sheds a new light on piezoelectric properties and surface defect engineering, while emphasizing the importance of surface properties in enhancing CO2 conversion performance.