Enhanced activity and selectivity of supported europium oxychloride catalysts for ethylene oxychlorination with HCl

Abstract A series of supported EuOCl catalysts, and bulk EuOCl catalyst were selected for ethylene oxychlorination with HCl to produce a VCM. The supported EuOCl catalysts showed higher ethylene conversion and VCM yield than those of bulk EuOCl despite the low Eu content. The EuOCl/Y catalysts demonstrated the highest ethylene conversion and VCM selectivity followed by EuOCl/Al2O3. The catalysts were characterized in terms of redox properties, acidic properties, and adsorption behavior of the reactant and product. The reduction temperature of europium species decreased when EuOCl was loaded on various supports. The activity of HCl oxidation is strongly related to the improved redox properties, resulting in better activation of the reactant. We demonstrated that the number of acidic sites was proportional to the dehydrochlorination activity of EDC. Investigation of the adsorption behavior of C2H4 showed that the number of oxygen vacancies increased on the supported EuOCl catalysts. EuOCl/Y and EuOCl/Al2O3 catalysts, showed good catalytic performance, exhibited better redox and acidic properties, and had higher amounts of oxygen vacancies than the other catalysts. However, EuOCl/Y with excessively high acidity showed deactivation with time-on-stream owing to carbon deposition. Therefore, EuOCl/Al2O3 was found to be the most suitable supported catalyst for the oxychlorination of ethylene.