Comparative studies of leached Pt-Fe and Pt-Co catalysts for CO oxidation reactions

Abstract

Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure of metal oxides decorating the surface of nanoparticles. The fully oxidized Fe 2 O 3 and Co 3 O 4 species on Pt nanoparticle surfaces result in the low performance of the CO complete oxidation (COOX) reaction. In contrast, unsaturated FeO and CoO surface species can be formed during exposure to the CO preferential oxidation (CO-PROX) reaction with an excess of H 2 , leading to a high O 2 activation ability and enhancing the CO-PROX activity. The FeO x surface structures can be transformed between these two states by varying the reactive gas environments, exhibiting oscillating activity in these two reactions. Conversely, the CoO surface structure formed in the H 2 -rich atmosphere is stable when exposed to the COOX reaction and exhibits similar activity in these two reactions. It is hoped that this work may assist in understanding the important role of surface oxides in real reactions. The structure of metal oxides on nanoparticle surfaces can be obtained by oxidizing the leached Pt-Fe and Pt-Co catalysts. The relationship between surface oxides and the catalytic performance for CO oxidation reactions was studied.