Bifunctional catalysts for coupled NH ₃ -SCR and CO oxidation: recent advances and future perspectives

Simultaneous removal of carbon monoxide (CO) and nitrogen oxides (NOx) has become a hot topic in environmental catalysis. Developing bifunctional catalysts capable of simultaneously catalyzing NH3-SCR and CO oxidation reactions is key to achieving the removal of both pollutants. This paper systematically reviews the latest research progress in catalytic systems based on noble metals, transition metal oxides, zeolites, and hydrotalcite-derived materials, focusing on the design of active sites, synergistic reaction mechanisms, and strategies for resistance to H2O and SO2. The effects of synergistic interactions among multiple active components, support structure regulation (such as confinement effects), and precise balancing of surface acidity/redox properties on the performance of the catalysts have been discussed. The long-term stability and poisoning resistance of catalysts in complex flue gas environments are also analyzed. Furthermore, current scientific challenges and future directions for the coupled NH3-SCR and CO oxidation processes are presented. This work aims to provide insight for designing more efficient catalysts for the simultaneous removal of NOx and CO.