Light-Induced Generation and Regeneration of Oxygen Vacancies in BiSbO4 for Sustainable Visible Light Photocatalysis

Oxygen vacancy (OV)-containing semiconductor photocatalysts have been extensively studied and applied in environmental and energy fields, but there are a few studies concerning the mechanisms of inactivation and regeneration of OVs to prevent the catalysts from deactivation. In this paper, we put forward a novel in situ method to introduce the OVs into BiSbO4 (BiSbO4-OV) via UV-light-induced breaking down of Bi-O and Sb-O bonds. The formation of OVs could broaden the photoresponse range and improve the charge carrier separation as confirmed by density functional theory calculation and UV and photoluminescence spectroscopy. The unique electronic structure of OVs endowed BiSbO4 with high visible light photocatalytic NO activity. It was significant to reveal that oxygen in the air could fill the OV sites during the photocatalytic reaction and the consumption of the OVs led to the direct deactivation of BiSbO4-OV. By re-irradiation of the deactivated photocatalysts, BiSbO4-OV could get back to its initial state, realizing the refreshment of OVs for sustainable photocatalysis. Additionally, the visible light photocatalytic NO conversion pathway on BiSbO4-OV was uncovered via in situ diffuse reflectance infrared Fourier transform spectroscopy based on the identification of the reaction intermediates and products. The light-induced generation and regeneration of OVs could also be extended to other semiconductors for sustainable visible light photocatalysis.