SINGLE-ATOM ALLOY Pd₁Ag₆/Al₂O₃ EGG-SHELL CATALYST FOR SELECTIVE ACETYLENE HYDROGENATION

Abstract

In this work, a single-atom alloy Pd1Ag6/Al2O3 catalyst for the selective hydrogenation of acetylene was obtained with an egg-shell distribution of the active phase over the catalyst granules. The formation of an egg-shell structure was confirmed by electron probe microanalysis. It was found that metals are predominantly localized at a depth of 130–160 µm from the surface of the granules. Transmission electron microscopy and X-ray photoelectron spectroscopy have revealed the formation of a substitutional PdAg solid solution with electron density transfer from Ag to Pd. The formation of Pd1 single sites was confirmed by FTIR spectro-scopy of adsorbed CO. In the selective hydrogenation of acetylene the synthesized single-atom alloy Pd1Ag6/Al2O3 with egg-shell distribution showed high selectivity, which radically exceeds the selectivity of the palladium counterpart.