10^th European Organic Chemistry Congress

Biography

Biography: Xiaolong Liu

Abstract

Volatile organic compounds (VOCs) emitted from the industrial plants are toxic and are dangerous to human health. Among the abundant VOCs pollutants, chlorinated volatile organic compounds (OVOCs), including chlorobenzene (CB), dichloromethane (DCM), 1, 2-dichloroethane (DCE), and trichloroethylene (TCE), are regarded as an important group of VOC pollutants due to its high toxicity, strong stability, and poor reactivity. In comparison to other noble metals (Pd, Pt, Rh), Ru catalysts have been far less explored in environmental catalysis. Recently, Ru catalysts have been well demonstrated in catalytic oxidation of alkanes, alkenes, aromatics, and some halogenated volatile organic compounds. In this work, noble metal catalysts (Pd, Pt, Ru, and Rh) were prepared and evaluated in the catalytic oxidation chlorobenzene, and Ru/TiO₂ contributed the best catalytic performance. During the oxidation, polychlorinated benzenes PhCl_x (x≥2) were observed, and Ru/TiO₂ showed apparently lower PhCl_x concentrations than other three samples. Besides, the dioxin-like PCBs (dl-PCBs) were collected and analyzed for Pd/TiO₂ and Ru/TiO₂. The ∑dl-PCBs produced by Pd/TiO₂ was about 1.5 times that of Ru/TiO₂. XPS analyses revealed that Ru/TiO₂-used gave the lowest Cl content among the used catalysts, and the lowest (Cl_ad+Cl_or)/Cl value and the highest Cl_br/Cl value, which might be an important reason for its strongest chlorine removal ability and the lowest yields of polychlorinated by-products. In-situ FTIR studies were also conducted for Pd, Pt, Ru, and Rh catalysts, and various organic intermediates were observed on the catalyst surface. Besides, density functional theory (DFT) was also conducted to investigate the main reason for the difference of the catalytic performance of Ru and other three samples (Pd, Pt, and Rh). Accordingly, a reaction mechanism for the catalytic oxidation of chlorobenzene was proposed