Influence of Copper on the catalytic activity of supported Rhodium Catalysts in the reactions of CO oxidation and NO reduction

L. A. Petrov1, J. Soria2, R. Cataluna2

1Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl.11, Sofia 1113, Bulgaria

2Instituto de Catalisis y Petroleoquimica, CSIC, Camino de Valdelatas, s/n.- Campus Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain

Abstract

The catalytic activity of Cu, Rh, and Rh/Cu, catalysts supported on Al2O3, CeO2 and CeO2/Al2O3 in reactions of CO oxidation and NO reduction has been studied in temperature-programmed regime. Addition of Cu to Rh catalysts decreases temperature at which 5 and 50% degree of conversion, while end of reaction temperature is not influenced by presence of Cu. The presence of Cu has positive effect on the activity of Rh containing catalysts in the low temperature region. Cu has noticeable promoting effect mainly for the catalytic activity in the reaction of CO oxidation and in smaller extent for the reaction of NO reduction. Preliminary redox treatment of the catalysts decreases the light off temperature in the reactions of CO oxidation and in NO reduction. Thermal treatment at temperatures up to 973 K does not have sensible effect on the catalytic activities of all studied catalysts. Calcination at 1073 K, however, strongly decreases the catalytic activity of Rh/Cu/CeO2/Al2O3 catalysts.