Adsorption of acrolein on single-crystal surfaces of silver: Density functional studies

Silver selectively catalyzes the hydrogenation of the CO group of α, β-unsaturated aldehydes, indicating preferential adsorption-induced activation of this bond compared to the adjacent CC bond. Using a density functional method and periodic slab models, we studied the propensity of the flat Ag(1 1 0) and the stepped Ag(2 2 1) surfaces to activate the CO bond of adsorbed acrolein. Our calculations show acrolein to interact only weakly with all adsorption sites under study (by at most 35 kJ mol^-1), resulting in very limited bond activation. Therefore, we conclude that other active sites on silver catalysts participate in the experimentally observed selective hydrogenation.