Cerium-doped UiO-66-supported Pd catalysts: activity enhancement and deactivation pathways in the carbonylation of methyl nitrite to DMC

Abstract

For the carbonylation of methyl nitrite (MN) to dimethyl carbonate (DMC), a series of Ce_(x)-UiO-66 were synthesized and utilized as supports for Pd/Ce_(x)-UiO-66 catalysts. The characteristics of the carriers were investigated using XRD, SEM, TG, NH₃-TPD and BET analyses. The results showed that doping cerium in the UiO-66 significantly enhanced the catalytic activity by improving the surface area, acidity and CO adsorption of the catalysts. Ce_(0.1)-UiO-66, with the highest thermal stability (547.26 °C), presented the highest catalytic stability in DMC synthesis. It was proven that the damage of CO and the migration of Pd atoms occurred due to the replacement of ligands and metal clusters, which led to catalytic deactivation.