Environmental Catalysis for NOx Reduction by Manipulating the Dynamic Coordination Environment of Active Sites

Abstract

Nowadays, it is challenging to achieve SO₂-tolerant environmental catalysis for NO_x reduction because of the thermodynamically favorable transformation of reactive sites to inactive sulfate species in the presence of SO₂. Herein, we achieve enhanced low-temperature SO₂-tolerant NO_x reduction by manipulating the dynamic coordination environment of active sites. Engineered by coordination chemistry, SiO₂-CeO₂ composite oxides with a short-range ordered Ce–O–Si structure were elaborately constructed on a TiO₂ support. A dynamic coordination environment of active sites is demonstrated from a Ce–O–Si local structure to a low-coordinated Ce-SO₄^2– species in the presence of SO₂. The low-coordinated Ce-SO₄^2– species as new active sites maintain a high NO removal efficiency by preserving the good adsorption and activation capacity of NO and NH₃ reactants. This work proposes a new notion to improve the SO₂ resistance of catalysts by regulating the coordination environment of sulfated active sites, which is of significance for SO₂-tolerant environmental catalysis in practical applications.