Operando Ir/exafs studies of the promotion behavior of Pt-Nb2o5/Al2o3 catalysts during the preferential oxidation of Co

The promotion of Pt/Al2O3 with niobia (Nb2O5) was studied during the preferential oxidation of CO in the presence hydrogen (PROX reaction). A maximum of 65% CO2 was produced for the 5%Nb-promoted catalyst. The reduced Pt Nb-promoted catalysts exhibited Pt+2 species. As Nb loading increased, the decoration effect also increased and bigger aggregates of NbOx were formed. The same Pt particle size gave lower H2 adsorption when Nb loading increased. By adding niobia to Pt/Al2O3 catalysts, the catalytic activity on the PROX of CO can be improved. The semi-oxidized catalysts promoted with niobia showed higher activity for the preferential oxidation of CO than the fully reduced unpromoted Pt/Al2O3 catalyst. This is an abstract of a paper presented at the AIChE Annual Meeting (San Francisco, CA 11/12-17/2006).