Ultra-efficient Ru and Nb Co-Modified CeO₂ Catalysts for Catalytic Oxidation of 1,2-Dichloroethane

The oxidation of chlorinated volatile organic compounds on CeO₂ is hindered by its high susceptibility to chlorine poisoning, resulting in a reduced efficiency and stability. In this study, Ru- and Nb-co-modified CeO₂ catalysts were designed to achieve excellent activity, stability, and CO₂ selectivity in the catalytic oxidation of 1,2-dichloroethane (EDC). The formation of Nb-O-Ce bonds was observed to enhance the surface acidic sites, thereby improving HCl selectivity and reducing the production of chlorinated byproducts. Meanwhile, it inhibits the formation of Ru-O-Ce and promotes the generation of highly dispersed RuO₂ particles on the surface, enhancing the redox properties and mobility of the surface oxygen, thus increasing CO₂ selectivity. In situ diffuse reflectance infrared Fourier transform spectroscopy results revealed that chlorine species preferentially attach to Nb species rather than to oxygen vacancies on the Ru/Nb/CeO₂ catalyst. This allows more alkane groups to oxidize to formate on the oxygen vacancies, reducing byproduct concentration. Additionally, the oxidation of alkane groups to carboxylic acids is initiated on the Nb species, completing a comprehensive oxidation process under the synergistic effect of RuO₂.