Determination of the Rh-C bond energy for C2H2 and C2H4 reactive adsorption on Rh{100}

Coverage dependent heats of adsorption and sticking probabilities for ethyl ene and acetylene on Rh{100} have been measured. For C2H2 and C2H4, the ini tial heats of adsorption are 210 +/- 10 and 175 +/- 10 kJ mol(-1), and the initial sticking probabilities are 0.86 +/- 0.01 and 0.88 +/- 0.01, respect ively. No literature is available on the adsorption of acetylene on Rh{100} . However, it is known that ethylene adsorption on Rh{100} at 300 K produce s sigma-bonded C=CH, and the corresponding Rh-C bond energy is therefore es timated as similar to 268 kJ mol(-1). This is used to determine the species most likely to be formed upon acetylene adsorption. (C) 1999 Elsevier Scie nce B.V. ALI rights reserved.