Complete removal of carbon monoxide by functional nanoparticles for hydrogen fuel cell application

•Complete oxidation of CO was achieved at low temperature with Cu/Ce0.8Zr0.2O2 catalysts.•Complete CO oxidation at low temperature was attributed to high oxygen storage capacity of the catalysts.•The contribution of oxygen species in achieving the complete conversion was investigated and explained.

A bi-functional catalyst containing a stable cubic cerium-zirconium oxide phase was prepared and used for CO preferential oxidation. Pure ceria was observed to achieve the highest CO conversion of over 95% at >300 °C. A bi-functional ceria-zirconia successfully reduced the reaction temperature to 200 °C but at the expense of lower conversion of 85%. The bi-functional catalyst containing copper species at 5 wt% of the metal precursor demonstrated the ability to oxidize CO completely at 115 °C. This was made possible by the high oxygen storage capacity (OSC) of the catalyst which was measured to be 707.7 μmol O2/g.