Carbon Monoxide Oxidation on a Pt(110) Single Crystal Surface

Abstract

The catalytic reaction between CO and O2 on a Pt (110) surface is investigated by residual gas analysis for different partial pressures of CO and O2 and various temperatures. The surface cleanliness of the Pt crystal is monitored by Auger electron spectroscopy. The results of the reaction study are generally in agreement with previous studies for polycrystalline Pt catalysts. The temperature dependence of the formation rate of CO2 exhibits a maximum whose position depends on the composition of the gas phase. At T=215°C two different rate laws are valid. For PO2>PCO the rate of CO2 formation is proportional to PO21.1PCO−0.6, while for PO2>PCO it is proportional to PO20.25 PCO0.75. These observations support the idea that the reaction obeys an Eley-Rideal mechanism in the pressure and temperature range investigated, and the results are evaluated accordingly. The influence of segregated Si on the CO oxidation reaction is investigated and found to be small.