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

The catalytic oxidation of gaseous HCl with a small amount of HF to Cl-2 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.