Abstract: A new bimetallic catalyst was characterized consisting of individual Pd atoms dispersed on a Ag(111) host metal. Using infrared spectroscopy and mass spectrometry of adsorbed CO, the Pd/Ag(111) single-atom alloy (SAA) surface was studied as a function of both annealing and surface deposition temperature. The SAA surface was used to study the effects of atomic hydrogen adsorption and selective hydrogenation of acrolein to 2-propenol and acetylene to ethylene.

Based on reflection absorption infrared spectroscopy (RAIRS), we determine the adsorption geometries of the starting materials which gives insight towards favorable reaction pathways. The hydrogenation of acrolein and acetylene was studied using temperature programmed reaction spectroscopy (TPRS) to determine the conversion of the starting materials and the selectivity of each pathway. Based on our results, we show that dilute amounts of individual Pd atoms can have a profound effect on the reactivity compared to that adsorbed on Ag(111) and that the morphology of the SAA must be considered in industrial applications.