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 MO x (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 MO x dominate the activity for CO oxidation. The electron-deficient Pt due to the strong interaction between Pt and MO x leads to the weaker CO adsorption strength. Meanwhile, the higher reducibility of FeO x and CoO x extends the reaction routine due to the improved activity of oxygen with the help of the redox cycle between FeO x /CoO x and CeO2. However, the stability of catalyst depends on the ability to recover consumed oxygen, and the reversible compensation of consumed oxygen species makes CoO x /Pt/CeO2 and NiO x /Pt/CeO2 remain stable with time on stream. Our study shows that CoO x is a potential candidate to increase Pt atom efficiency for CO oxidation on Pt/CeO2 catalysts.