Three-in-One Oxygen Vacancies: Whole Visible-Spectrum Absorption, Efficient Charge Separation, and Surface Site Activation for Robust CO2 Photoreduction.

A facile and controllable in situ reduction strategy is used to create surface oxygen vacancies (OVs) on Aurivillius-phase Sr2 Bi2 Nb2 TiO12 nanosheets, which were prepared by a mineralizer-assisted soft-chemical method. Introduction of OVs on the surface of Sr2 Bi2 Nb2 TiO12 extends photoresponse to cover the whole visible region and also tremendously promotes separation of photoinduced charge carriers. Adsorption and activation of CO2 molecules on the surface of the catalyst are greatly enhanced. In the gas-solid reaction system without co-catalysts or sacrificial agents, OVs-abundant Sr2 Bi2 Nb2 TiO12 nanosheets show outstanding CO2 photoreduction activity, producing CO with a rate of 17.11 μmol g-1  h-1 , about 58 times higher than that of the bulk counterpart, surpassing most previously reported state-of-the-art photocatalysts. Our study provides a three-in-one integrated solution to advance the performance of photocatalysts for solar-energy conversion and generation of renewable energy.