Advances in CO catalytic oxidation on typical metal oxide catalysts: performance, mechanism, and optimization

As industrialization accelerates, the emission of carbon monoxide (CO) has become an increasingly pressing issue, posing significant threats to human health and environmental safety. Catalytic oxidation is a cost-effective and efficient technology that significantly reduces CO concentrations. Metal oxide catalysts have demonstrated significant research value in the field of CO catalytic oxidation due to their low cost, excellent redox properties, and abundant oxygen vacancies. This review focuses on the application of metal oxides in CO catalytic oxidation, covering typical catalysts, reaction mechanisms, and optimization strategies. It systematically summarizes the physicochemical properties (such as specific surface area, lattice structure, oxygen vacancies, and metal ion valence states) of typical metal oxides and composite catalysts, including CuO_x, MnO_x, CeO_x, and CoO_x, and their effects on CO oxidation performance. The reaction mechanisms for CO catalytic oxidation, including the Langmuir–Hinshelwood, Mars–van Krevelen, and Eley–Rideal models, are analyzed in detail. Additionally, this review examines how reaction conditions, including H₂O and SO₂, affect catalyst performance. To address challenges such as insufficient low-temperature activity, weak resistance to poisoning, and instability under complex conditions, this review proposes two major optimization directions: enhancing low-temperature activity and improving resistance to deactivation and stability. Specific optimization strategies, including defect engineering, crystal facet engineering, synergistic effects, interface effects, and directional modification, are summarized. Finally, this review discusses the core challenges and future development directions for the practical applications of metal oxide catalysts in industrial flue gas treatment and air purification, with insights from recent research advancements.