Atomically exposed Pd catalysts covered by boron nitride for highly selective hydrogenation of acetylene

The selective hydrogenation of acetylene to remove trace acetylene in ethylene plays a significant role in the ethylene polymerization industry. Herein, boron nitride (BN) was selected for encapsulating Pd nanoparticles to prepare a catalyst with atomic Pd sites exposed by a simple inorganic precursor-based strategy. This atomically exposed Pd catalyst favors the desorption of ethylene kinetically instead of further hydrogenation, which is the key for improving the selective hydrogenation of acetylene. With only atomic Pd exposure, the Pd@BN-0.5 catalyst reached 94% ethylene selectivity when acetylene conversion was 100% in a pure acetylene environment. More importantly, this atomically exposed Pd catalyst also showed an ethylene selectivity of 84.7% in ethylene-rich feed, which is the simulated environment for industrial production. Finally, this atomic exposure strategy was extended to PdAg@BN, where 96.9% ethylene selectivity in a pure acetylene environment and 88.7% ethylene selectivity in an ethylene-rich environment were obtained.