Atomically dispersed Pd atoms on a simple MgO support with an ultra-low loading for selective hydrogenation of acetylene to ethylene.

We report a simple and efficient Pd/MgO catalyst loaded with ppm level of Pd (7.8 ppm) for semi-hydrogenation of acetylene to ethylene. The catalyst showed excellent performance with high acetylene conversion (97%), high ethylene selectivity (89%) and good stability. Moreover, the atomically dispersed Pd atoms are inactive for ethylene hydrogenation. Isotopic and FTIR results suggest that H 2 dissociates at isolated Pd atoms in a heterolytic manner forming O-H bond, which may account for the high selectivity.