Selective Hydrogenation of Acrolein on a Pd/Ag(111) Single-Atom Alloy Surface

Abstract

The hydrogenation of acrolein on the Ag(111) and Pd/Ag(111) single-atom alloy (SAA) surfaces was studied using temperature-programmed reaction spectroscopy. On Ag(111), the percent conversion of acrolein increased with increasing atomic hydrogen coverage. At an acrolein coverage of 0.17 ML followed by a low exposure to atomic hydrogen, the highest selectivity to 2-propenol was reached at 19%. However, increasing the acrolein coverage caused the selectivity to 2-propenol to decrease and the selectivity to propanal to increase to a maximum of 92%. In all cases, increasing atomic hydrogen exposure decreased the selectivity to 2-propenol. The selectivity to 1-propanol was constant at only 1%. Activity and conversion on the Ag(111) and Pd/Ag(111) SAA surfaces were compared for Pd coverages of 0.2, 0.5, and 0.9%. With increasing Pd coverage, the percent conversion increased while the selectivity to 2-propenol decreased. The selectivity toward 1-propanol only increased from 1 to 3% for the 0.9% Pd/Ag(111) SAA surface.