H. Uetsuka, Kentaro Watanabe, K. Kunimori
Aug 1, 1996
Abstract IR emission spectra of CO 2 were measured during decomposition of HCOOH, HCOOH + O 2 reaction and oxidation of CO on metal surfaces for the study of the dynamics of the catalytic reactions. Vibrationally excited CO 2 was produced by HCOOH + O 2 reaction on Pt foil. Internal energy distribution of the product CO 2 was the same as that from CO oxidation on Pt foil (a bimolecular reaction between CO ad + O ad ). On the contrary, CO 2 molecules desorbed during HCOOH + O 2 reaction on Ni foil and decomposition of HCOOH on Pt or Ni foil were not so excited (a unimolecular reaction). On the other hand, the IR chemiluminescence of the product CO 2 was measured for the first time during the oxidation of CO on single crystal Pd(111) and Pt(111) surfaces. The vibrational ( T V ) and rotational ( T R ) temperatures of the CO 2 from Pd(111) were much higher than those of the CO 2 from Pt(111). Furthermore, the comparison of the results with those on polycrystalline Pd and Pt surfaces revealed that the reaction dynamics of CO oxidation are structure-sensitive; i.e., the transition state of CO 2 formation depends on the structure of the catalyst surface.