High Visible Light Photocatalytic Activity of SnO_2‐x Nanocrystals with Rich Oxygen Vacancy

Abstract

SnO2‐x nanocrystals were prepared using a simple hydrothermal method by controlling the proportions of Sn4+/Sn2+ precursors. Due to the doping of Sn2+, the oxygen vacancies could be introduced into SnO2 nanocrystals, and their concentration can be controlled by the amount of doping Sn2+. The structural characteristics of SnO2‐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 SnO2 while the in‐plane O‐vacancies play a key role in the SnO2‐x. Meanwhile, the higher Sn2+ concentration, the more structural disorder was produced. According to XPS analysis, the presence of oxygen defects will change the electronic structure of SnO2‐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.

A Novel Approach for Generation of Oxygen Vacancies in Trirutile MnSb2O6 and Their Impact on Photocatalytic Degradation of MO Dye

“…It is well established that the formation of oxygen vacancies is responsible for the shift in Raman peaks towards higher wavenumber and also decreased intensity of the peaks affirm the same. [38,41] As can be observed from Figure7, the apparent decrease in peak intensity associated with peak shift can be clearly observed for M-Sb(3 +)-1C containing the highest oxygen vacancies when compared to the other two samples. The intensity and shift in peak is consistent with the amount of oxygen vacancies present in the sample.…”

“…The VB XPS of the three samples is shown in Figure S2 (Supporting Information). Since the position of the valence band can be significantly affected by the presence of oxygen vacancies, we have analyzed the VB XPS spectra of all three samples [38] . The results reveal a clear decrease in E VB with increasing oxygen vacancies.…”

“…Since the position of the valence band can be significantly affected by the presence of oxygen vacancies, we have analyzed the VB XPS spectra of all three samples. [38] The results reveal a clear decrease in E VB with increasing oxygen vacancies. The E VB value of sample M-Sb(5 +)-4C with no oxygen vacancies is found at 2.08 eV, while that of oxygen-deficient samples shifted to 1.79 and 0.96 eV for M-Sb(3 +)-4C and M-Sb(3 +)-1C, respectively.…”

Enhanced NO2 Sensing Performance of ZnO-SnO2 Heterojunction Derived from Metal-Organic Frameworks

“…The band gap energies of S1, S2 and S4 were determined by Tauc-plot methods [ 30 ]. According to previous study, materials involved in this paper are direct band gap [ 31 , 32 ]. The estimated band gaps were 3.19, 3.22, and 3.63 eV for S1, S2 and S4, respectively.…”

Electrospun Porous Nanofibers: Pore−Forming Mechanisms and Applications for Photocatalytic Degradation of Organic Pollutants in Wastewater

“…Photocatalysis is a simple and efficient technology for photocatalysts to remove pollutants by stimulating its oxidation−reduction ability through light. The common photocatalytic particles include CdS [ 100 , 101 ], SnO 2 [ 102 , 103 ], AgCl [ 104 ], and ZnO [ 105 , 106 , 107 ]. Single particles have limited applications due to their own light absorption, the compounding of electron−hole pairs, and lack of specific surface area.…”