Abstract
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•The oxygen vacancy in TiO2 has been tuned by annealing in different atmosphere.•The energy bandgap of gray and black TiO2 has been changed from 3.10 to 3.02 and 1.99 eV.•The content of oxygen vacancy is 1%, 4.8% and 7.8% for white, gray and black TiO2.•The photocatalytic performance is enhanced owing to the rich Ti3+ and oxygen vacancies.
White TiO2 (W-TiO2), gray TiO2 (G-TiO2) and black TiO2 (B-TiO2) have been prepared through simple annealing process in different atmospheres. The oxygen vacancy content in the TiO2 samples and the relationship between oxygen vacancy and photocatalytic performance have been studied by comprehensive analyses. The XRD peaks slightly move to a low angle and the Raman strongest peak shifts positively owing to oxygen vacancy and Ti3+. The energy bandgap of G-TiO2 and B-TiO2 is tuned from 3.10 to 3.02 and 1.99 eV. The content of oxygen vacancy is 1%, 4.8% and 7.8% for W-TiO2, G-TiO2 and B-TiO2, respectively. The efficiency of NO removal is stable at 34%, 38% and 45%, and the decomposition rate of Rhodamine B under visible light is 75%, 83% and 89% for W-TiO2, G-TiO2 and B-TiO2, respectively. The results are significant for the design of high-performance photocatalytic materials in the field of solar energy conversion.