Influence of small amounts of rhodium on the structure and the reducibility of Cu/Al2O3 and Cu/CeO2-A12O3 catalysts

International audience ; The influence of small amounts of rhodium on the structure and the reducibility of copper-based catalysts deposited on alumina and ceria-alumina supports has been studied by XRD and H2-TPR techniques. For both supports, the addition of rhodium does not affect the reduction mechanism of copper, which has been shown to involve small clusters/isolated ions at lower temperatures and large particles at higher temperatures. However, rhodium addition inhibits the formation of large size copper particles in favor of small ones, thus making easier the reduction of the catalyst at low temperature.