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.