CO preferential oxidation on Pt0.5Co0.5 and Pt-CoOx model catalysts: Catalytic performance and operando XRD studies

Nanopowders of unordered solid solution Pt0.5Co0.5 and metal-oxide composite Pt-CoOx were prepared via double complex salt [Pt(NH3)(4)][Co(C2O4)(2)(H2O)(2)]center dot 2H(2)O decomposition in He and air streams, respectively. It was shown that, compared to metallic Pt nanopowder, both Pt0.5Co0.5 and Pt-CoOx exhibited high CO preferential oxidation (CO PROX) performance under mild conditions and provided complete CO conversion with 50-100% selectivity at near-ambient temperature and WHSV of 80,000 cm(3) g(-1) h(-1). Operando XRD study revealed that under CO PROX conditions Pt0.5Co0.5 was stable, while Pt-CoOx underwent reduction even at 50 degrees C and consisted of Pt and Co nanoparticles. The high performance of both (alloyed and not alloyed) Pt-Co bimetallic systems exhibits the key role of Pt-Co interface, i.e. the so-called ensemble effect, in the synergism.