Effect of acidity and ruthenium species on catalytic performance of ruthenium catalysts for acetylene hydrochlorination

Abstract

Carbon-supported ruthenium catalysts are promising mercury-free catalysts for acetylene hydrochlorination, due to their high activity and relatively low price. However, ruthenium catalysts often suffer from serious deactivation. Herein, a stable RuCl₃-A/AC catalyst was prepared by applying a simple ammonia treatment during the impregnation process. The fresh and used ruthenium catalysts were comprehensively characterized using N₂ sorption, NH₃-temperature-programmed desorption (NH₃-TPD), H₂ temperature-programmed reduction (H₂-TPR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The results show that the RuCl₃ species is identified as the active species, and the surface acidity of the RuCl₃/AC catalyst is generated mainly from supported RuCl₃ species, which can easily cause coke deposition. The enhancement of the stability of the RuCl₃-A/AC catalyst is attributed to the formation of RuO_x species and the decrease of the surface acidity.