Insight into TiO2-supported RuO2 catalysts for the efficient oxidation of HCl to Cl2: role of oxygen vacancies on TiO2

Rutile-type TiO 2 supported RuO 2 catalysts show a remarkably low-temperature activity in the catalytic gas-phase oxidation of HCl to Cl 2 , i.e. , the Deacon process. Although it is found that the oxygen vacancies in TiO 2 can enhance the activity and stability of supported RuO 2 catalysts in the Deacon process, the role of oxygen vacancies in the catalytic performance has not been clearly illustrated yet. In the current study, oxygen vacancies were introduced onto TiO 2 through a straightforward yet highly effective treatment of the commercial rutile-TiO 2 with H 2 at an optimal reduction temperature of 600 °C, named TiO 2 -600, which was then used as the support for preparing RuO 2 /TiO 2 -600 via an incipient wetness impregnation method. The comprehensive characterizations of TiO 2 , TiO 2 -600, and their supported RuO 2 catalysts conclusively demonstrate that the introduced oxygen vacancies on TiO 2 are consumed for the formation of the RuO 2 nanoparticles with the enhanced RuO 2 dispersion and the increased interactions between RuO 2 and TiO 2 -600, resulting in the higher catalytic activity and stability of RuO 2 /TiO 2 -600 in the Deacon process, compared to RuO 2 /TiO 2 . Consequently, this study not only clarifies the role of oxygen vacancies on TiO 2 but also offers valuable insights to guide the development of Deacon catalysts with a high low-temperature activity and a long-term stability.