Effect of oxygen vacancies and its quantity on photocatalytic oxidation performance of titanium dioxide for NO removal

Abstract In this work, black TiO2 catalysts containing a large number of oxygen vacancies were prepared by sol-gel and calcination methods. The catalytic activity of the photocatalysts was evaluated by photocatalytic oxidation removal of NO. We found that black TiO2 calcined at 400 °C in an N2 atmosphere with appropriate oxygen vacancy removes up to 71.3 % of NO in 90 min under the illumination of UV light, which was significantly better than other samples. The prepared catalyst was characterized by X-ray diffraction, Raman spectroscopy, UV–vis, XPS, EPR, BET surface area analysis and Photo-electrochemical test. These results showed that oxygen vacancies played an important role in the photocatalytic NO removal process. An appropriate amount of oxygen vacancies in catalyst benefits the aggregation of electrons in oxygen vacancies and a large number of electrons reacted with H2O2 and NO under UV light, thereby the activity enhanced. It was also found through EPR that the number of oxygen vacancies increased with the rise of temperature, which means that the number of oxygen vacancies would affect the catalyst performance.