Highly active and stable RuO2/MgF2 catalysts for efficient HCl oxidation in the fluorochemical industry

Abstract

The catalytic oxidation of gaseous HCl with a small amount of HF to Cl₂ is important and highly desired for chlorine recycling in the fluorochemical industry. In this work, a series of partly hydroxylated magnesium fluorides were prepared via fluorolytic and solvothermal synthesis methods at different solvothermal reaction times and used as supports to prepare RuO₂/MgF₂ catalysts via an incipient impregnation method. Both supports and catalysts were extensively characterized with different techniques to gain insight into their physicochemical properties. Furthermore, these prepared RuO₂/MgF₂ catalysts were evaluated in the oxidation of HCl with a HF concentration of 400 ppm. It is found that at an optimal solvothermal reaction time, the bridging –OH groups can be abundantly formed on MgF₂, which can significantly enhance the adsorption of the Ru-complex anions via an electrostatic attraction during the impregnation to greatly increase the dispersion of RuO₂ on MgF₂ and affect the chemical environment of RuO₂, resulting in pronounced catalytic activity and stability. The current study, therefore, provides a strategy to develop an efficient catalyst for the oxidation of HCl contaminated with HF.