Abrupt increase in hydrogen diffusion on transition-metal surfaces during hydrogenation catalysis

A sharp increase in the rate of hydrogen isotope scrambling was identified during the hydrogenation of olefins with H(2) + D(2) mixtures on Pt(111) catalysts, which spectroscopic data suggest is due to a sudden increase in atomic hydrogen surface mobility because of a decrease in the size of the islands of the adsorbed hydrocarbons.