K+-Modified Redox Properties of the CuOx/CeO2 Catalyst for Highly Efficient CO Oxidation

CuO_x/CeO₂ is emerging as an effective catalyst for CO oxidation due to its unique redox properties; however, its activity and stability still need to be enhanced compared with supported platinum group metals. Here, an approach is demonstrated to increase the CO oxidation performance and resistance to hydrocarbon inhibition through the K⁺ modification of the CuO_x/CeO₂ catalyst. The K⁺ can improve the electron transfer at the metal–oxide interface, shifting the redox equilibrium (Cu²⁺ + Ce³⁺ ↔ Cu⁺ + Ce⁴⁺) to be right to accelerate the formation of highly active Cu⁺ species. The reaction activity of the K⁺-modified CuO_x/CeO₂ catalyst was in the same order of magnitude as the noble metal of Pt and Pd catalysts. In addition, the K⁺-modified catalyst showed significantly improved resistance to hydrocarbon inhibition. This work demonstrates a facile way to tune the redox properties of binary transition metal oxides.