High Visible Light Photocatalytic Activity of SnO<sub>2‐x</sub> Nanocrystals with Rich Oxygen Vacancy
Quan Liu, Hongquan Zhan, Xuchun Huang, Yihui Song, Shenchao He, Xiaohong Li, Chang‐An Wang, Zhipeng Xie
Abstract
Abstract SnO 2‐x nanocrystals were prepared using a simple hydrothermal method by controlling the proportions of Sn 4+ /Sn 2+ precursors. Due to the doping of Sn 2+ , the oxygen vacancies could be introduced into SnO 2 nanocrystals, and their concentration can be controlled by the amount of doping Sn 2+ . The structural characteristics of SnO 2‐x nanocrystals was investigated by X‐ray diffraction, Fourier transform infrared spectra, Raman spectra, UV‐vis diffuse reflectance, photoluminescence spectra and X‐ray photoelectron spectroscopy. The results reveal that the bridging O‐vacancies are dominant in the pure SnO 2 while the in‐plane O‐vacancies play a key role in the SnO 2‐x . Meanwhile, the higher Sn 2+ concentration, the more structural disorder was produced. According to XPS analysis, the presence of oxygen defects will change the electronic structure of SnO 2‐x nanocrystals, which will lead to the valence band moving up and the smaller band gap. The rich oxygen vacancies, the structural disorder and the narrow band gap should greatly improve the visible light harvesting, and result in the excellent photocatalytic activity.