TPR INVESTIGATION OF BIMETALLIC RU-CU SAMPLES SUPPORTED ON SIO2, AL2O3 AND MGO

Bimetallic Ru-Cu samples supported on SiO//2, Al//2O//3 and MgO were studied by the temperature-programmed reduction (TPR) technique. Experiments were carried out both on unreduced impregnated salts and after oxidation of already reduced samples. The TPR profiles reveal a simultaneous reduction of ruthenium and copper precursors, even though the Ru and Cu in the monometallic catalysts exhibit reduction peaks which differ by up to 150 degree C. It is suggested that the two metal salts interact during the stages of preparation and drying, and after reduction form bimetallic aggregates which are not stable and tend to separate. The stability of the bimetallic particles was found to be strongly dependent on the support used, being higher on SiO//2 than on Al//2O//3 and MgO. It is suggested that the chemical nature of the support determines the different degree of interaction and/or agglomeration of the bimetallic particles.