Comparison of structure and catalytic performance of Pt–Co and Pt–Cu bimetallic catalysts supported on Al2O3 and CeO2 synthesized by electron beam irradiation method for preferential CO oxidation

In order to investigate the effect of transition metal addition to platinum with different support materials on preferential CO oxidation, structure and chemical properties of supported bimetallic catalysts prepared by electron beam irradiation method were correlated to the catalytic performance. On Al2O3, decoration of Pt by small amount of Co (Co/Pt ∼ 0.03) drastically increased CO and O2 conversions while addition of equimolar Cu to Pt increased them only above 100 °C, where the rate-controlling factor was suggested to change from oxygen transport to CO activation. On CeO2, either addition of Co or Cu to Pt had minor or negative effect on high O2 conversion inherent to high oxygen transport at Pt–CeO2 interface. On Pt–Cu/CeO2, however, metal-CuOx interface dominates the reaction characteristics to give improved selectivity, which is suitable for deep CO removal in excess O2/CO condition. The order of selectivity above 100 °C, Pt–CoOx > Pt(alloy)–CuOx > Pt–CeO2 interfaces, was derived from structural analysis and catalytic tests.

► By electron beam irradiation, CoOx was loaded on Pt nanoparticles for Pt–Co catalyst. ► CuOx was loaded on both Pt–Cu alloy and support surface for Pt–Cu catalyst. ► CoOx on Pt particles ruled oxygen transport in PROX for Pt–Co/Al2O3 catalyst. ► O2 activation on Pt–Cu catalyst was essentially different from Pt and Pt–Co (>100 °C). ► The selectivity order was Pt–CoOx >metal (alloy)-CuOx >Pt–CeO2 interfaces (>100 °C).