Dual Active Sites of CO Adsorption and Activation over PtCu Alloy Nanocages for Preferential Oxidation of Carbon Monoxide

Abstract

Nanoarchitecture alloy materials represent a class of highly efficient and stable catalysts in heterogeneous catalysis. An intrinsic challenge has been seeking catalysts that can fulfill activity, selectivity, and durability requirements in the reaction. Herein, we exploit PtCu nanocage catalysts constituted by the PtCu alloy nanoparticles. The nanocage PtCu catalyst with cuboctahedron morphology is highly active for complete CO conversion within a temperature window of 115–155 °C in the preferential oxidation of CO (CO-PROX), attributable to a substantial change in the surface electronic properties due to the transfer of more electrons from Cu to Pt atoms. The two pathways for CO oxidation based on the analysis of experimental data are clarified on the surface of PtCu alloys and on the Cu+ derived from the reduction of oxidized Cu2+ species in the H2-rich reaction stream during CO-PROX. A time-on-stream isothermal experiment for 40 h reveals that the nanocage PtCu catalyst with cuboctahedron morphology possesses good resistance to H2O inhibitor.