Effect of Cu modification to Ru/HZSM-5 catalysts on the catalytic combustion of vinyl chloride†

Abstract

Vinyl chloride is a crucial raw material for producing polyvinyl chloride. Improper emissions of vinyl chloride during production can cause significant harm to ecosystems and human health. In this work, we prepared Cu-modified Ru/HZSM-5 catalysts by the impregnation method, and investigated the effect of Cu addition on the catalytic combustion of vinyl chloride. The catalytic activity of the Ru/HZSM-5 catalyst was significantly promoted by Cu modification. The T₉₀ of the Ru–2Cu/HZSM-5 catalyst was reduced by 68 °C compared to that of the Ru/HZSM-5 catalyst. The promotion effect of Cu modification was also reflected in the catalytic combustion performance of 1,2-dichloroethane. However, the introduction of Cu had a negative effect on the by-product selectivity. Further modifying the Ru–2Cu/HZSM-5 catalyst with Nb effectively improved selectivity to by-products. The Ru–2Cu/HZSM-5 catalyst also exhibited better cycling stability and water resistance stability than the Ru/HZSM-5 catalyst. Catalyst characterization results showed that the addition of Cu promoted Ru dispersion. Furthermore, the modification with Cu significantly enhanced the redox ability and oxygen mobility of the catalysts, resulting in improved catalytic activity. Additionally, in situ DRIFTS experiments were employed to propose the reaction mechanism for vinyl chloride oxidation over the Ru–2Cu/HZSM-5 catalyst.