The interaction of carbon dioxide with Cu(100)

Abstract

The binding energy for CO2 adsorbed on Cu(100) has been determined by use of TPD and was found to increase with increasing coverage from 25 to 30 kJ mol−1. The CO2 desorption temperature increased from 86 to 90 K with increasing coverage. The dissociative adsorption of CO2 on Cu(100) at a CO2 pressure of 990 mbar and a temperature range of 475–550 K has been investigated by XPS. The dissociative adsorption of CO2 was found to have an activation energy of 93±5 kJ mol−1 and to have a sticking coefficient of 7.5 × 10−12 at 500 K. The process reaches equilibrium under our experimental conditions. The heat of reaction was calculated to 70±4 kJ mol−1. Finally, from the CO2 result, the heat of reaction for the dissociative adsorption of O2 on Cu(100) was estimated. The latter being in good agreement with values measured on polycrystalline Cu.