Oxygen vacancies confined in SnO2 nanoparticles for glorious photocatalytic activities from the UV, visible to near-infrared region

For the purpose of effectively utilizing solar energy, tailoring of the energy band configuration represents an effective approach to the exploration and development of full-spectrum-responsive photocatalysts with advanced performance. In this work, we developed SnO2 nanoparticles with an adjusted energy band configuration by introducing oxygen vacancies (OV-SnO2) via a one-step hydrothermal process. The existence of oxygen vacancies was confirmed by XPS, ESR and PL. VB-XPS measurements and the UV-Vis-NIR absorption spectrum reveals that the introduction of oxygen vacancies increased the valence band width, resulting in a narrowed bandgap and increased photoabsorption. The obtained OV-SnO2 with a desirable energy band configuration exhibits superior full-spectrum-responsive photocatalytic activity under either UV, visible or even near-infrared light irradiation for the photodegradation of methyl orange (MO), which is completely accomplished within only 60 min under the condition of near-infrared light irradiation. The photocatalytic mechanism of full-spectrum-responsive photoreactivity, attributed to the narrowed bandgap and the broadened valence band width, was also revealed. The narrowed bandgap further contributes to the extended light absorption range and the broadened valence band width leads to efficient charge transfer and separation, hence revealing an outstanding full-spectrum-responsive photoreactivity. This research could shed light on general doping strategies for designing efficient photocatalysts and facilitate their application in environmental protection.