Selective Hydrogenation Reactions on Ag(111)and Pd/Ag(111) Single-Atom Alloy Surfaces

A new bimetallic catalyst is characterized using surface science techniques. The catalyst consists of individual Pd atoms dispersed on a Ag(111) host metal. Using infrared spectroscopy and mass spectrometry, the Pd/Ag(111) single atom alloy (SAA) surface is investigated based on the Ag(111) temperature upon evaporation and annealing of the alloyed surface. The SAA surface was used to study the effects of atomic hydrogen adsorption and selective hydrogenation of acrolein and acetylene to 2-propenol and ethylene. Infrared spectroscopy was used to gain insight into the adsorption geometries of the reactants on the Ag(111) and Pd/Ag(111) SAA surface. Hydrogenation of acrolein and acetylene were studied using mass spectrometry to determine the conversion of the starting materials and the selectivity to the desired products. Based on our results, we show that dilute amounts of individual Pd atoms can have a profound effect on the reactivity for acrolein and acetylene with atomic hydrogen compared to that adsorbed on Ag(111).