SO 2 -Tolerant Catalytic Reduction of NO x via Tailoring Electron Transfer between Surface Iron Sulfate and Subsurface Ceria.

Currently, SO 2 -induced catalyst deactivation from the sulfation of active sites turns to be an intractable issue for selective catalytic reduction (SCR) of NO x with NH 3 at low temperatures. Herein, SO 2 -tolerant NO x reduction has been originally demonstrated via tailoring the electron transfer between surface iron sulfate and subsurface ceria. Engineered from the atomic layer deposition followed by the pre-sulfation method, the structure of surface iron sulfate and subsurface ceria was successfully constructed on CeO 2 /TiO 2 catalysts, which delivered improved SO 2 resistance for NO x reduction at 250 °C. It was demonstrated that the surface iron sulfate inhibited the sulfation of subsurface Ce species, while the electron transfer from the surface Fe species to the subsurface Ce species was well retained. Such an innovative structure of surface iron sulfate and subsurface ceria notably improved the reactivity of NH x species, thus endowing the catalysts with a high NO x reaction efficiency in the presence of SO 2 . This work unraveled the specific structure effect of surface iron sulfate and subsurface ceria on SO 2 -toleant NO x reduction and supplied a new point to design SO 2 -tolerant catalysts by modulating the unique electron transfer between surface sulfate species and subsurface oxides.