Adsorption of CO on Pd/Al2O3/Ta(110) model catalysts

Abstract

The adsorption of CO on Pd/Al2O3/Ta(110) model catalysts was studied using infrared reflection adsorption spectroscopy (IRAS) for two different Pd coverages, corresponding to 25–30 and 60–70 Å average particle sizes. Striking similarities between the IRAS data for the larger particles and Pd single crystals indicate that the particles are comprised predominantly of 〈111〉 and 〈100〉 facets. The isosteric heat of adsorption of CO extrapolated to zero coverage was determined to be 38.9 kcal/mol on the 60–70 Å particles. IRAS and Auger results provide evidence of CO dissociation on the smaller particles.