Energy Transfer Dynamics of Formate Decomposition on Cu(110)

Energy transfer dynamics of formate (HCOOa) decomposition on a Cu(110) surface has been studied by measuring the angle-resolved intensity and translational energy distributions of CO2 emitted from the surface in a steady-state reaction of HCOOH and O-2. The angular distribution of CO2 shows a sharp collimation with the direction perpendicular to the surface, as represented by cosn q (n=6). The mean translational energy of CO2 is measured to be as low as 100 meVand is independent of the surface temperature (T-s). These results clearly indicate that the decomposition of formate is a thermal non-equilibrium process in which a large amount of energy released by the decomposition reaction of formate is transformed into the internal energies of CO2 molecules. The thermal non-equilibrium features observed in the dynamics of formate decomposition support the proposed Eley-Rideal (ER)-type mechanism for formate synthesis on copper catalysts.