Collect. Czech. Chem. Commun. 1992, 57, 2565-2574

Surface Reactivity of Rh Clusters on ZrO2 Modified by Mn, Fe and Mo

Sergio Marengoa, Hans Miessnerb, Annette Trunschkeb, Secondo Martinengoc and Luciano Zanderighid

a Stazione Sperimentale per i Combustibilli, V. le A. de Gasperi 3, 20097 San Donato Milanese, Italy
b Zentrum für Heterogenese Katalyse, Rudower Chaussee 5, D(O)-1199 Berlin, Germany
c Dipartimento di Chimica Inorganica a Metallorganica e Centro CNR sui Bassi Stati di Ossidazione, Università di Milano, Via Venezian 21, 20133 Milano, Italy
d Dipartimento di Chimica Fisica ed Elettrochimica, Università di Milano, Via Venezian 21, 20133 Milano, Italy


The reactivity of Rh clusters supported on ZrO2 and on ZrO2 modified by chemisorption of Mn, Fe, Mo carbonyls has been studied by various surface techniques such as TPD, TPR, FTIR, and by model reactions: Boudouard reaction, ethylene hydroformylation and CO/H2 reaction. Four CO adsorbed species have been identified and the main effect of the modifiers is to change the distribution of the various CO moieties present on the surface, as shown by TPR and reactivity data. Mn promotes methanol formation, Fe oxygenated compounds and chain growth, Mo increases the CO reactivity, mainly to oxygenates.