A Facile Way To Improve Pt Atom Efficiency for CO Oxidation at Low Temperature: Modification by Transition Metal Oxides

It is very challenging to improve the catalytic activity of Pt-based catalysts since the strong CO chemisorption on Pt inhibits oxygen activation leading to poor activity at low temperature. Here, we report that introducing MOx (M = Fe, Co, Ni) to modify Pt catalysts (0.5 wt % Pt/CeO2) is a facile way to improve catalytic activity for CO oxidation at ambient temperature. The chemical state of Pt and the reducibility of doped MOx dominate the activity for CO oxidation. The electron-deficient Pt due to the strong interaction between Pt and MOx leads to the weaker CO adsorption strength. Meanwhile, the higher reducibility of FeOx and CoOx extends the reaction routine due to the improved activity of oxygen with the help of the redox cycle between FeOx/CoOx and CeO2. However, the stability of catalyst depends on the ability to recover consumed oxygen, and the reversible compensation of consumed oxygen species makes CoOx/Pt/CeO2 and NiOx/Pt/CeO2 remain stable with time on stream. Our study shows that CoOx is a potential candidate to increase Pt atom efficiency for CO oxidation on Pt/CeO2 catalysts.