Boosting SO 2 -Resistant NO x Reduction by Modulating Electronic Interaction of Short-Range Fe-O Coordination over Fe 2 O 3 /TiO 2 Catalysts.

SO 2 -resistant selective catalytic reduction (SCR) of NO x remains a grand challenge for eliminating NO x generated from stationary combustion processes. Herein, SO 2 -resistant NO x reduction has been boosted by modulating electronic interaction of short-range Fe-O coordination over Fe 2 O 3 /TiO 2 catalysts. We report a remarkable SO 2 -tolerant Fe 2 O 3 /TiO 2 catalyst using sulfur-doped TiO 2 as the support. Via an array of spectroscopic and microscopic characterizations and DFT theoretical calculations, the active form of the dopant is demonstrated as SO 4 2- residing at subsurface TiO 6 locations. Sulfur doping exerts strong electronic perturbation to TiO 2 , causing a net charge transfer from Fe 2 O 3 to TiO 2 via increased short-range Fe-O coordination. This electronic effect simultaneously weakens charge transfer from Fe 2 O 3 to SO 2 and enhances that from NO/NH 3 to Fe 2 O 3 , resulting in a remarkable "killing two birds with one stone" scenario, that is, improving NO/NH 3 adsorption that benefits SCR reaction and inhibiting SO 2 poisoning that benefits catalyst long-term stability.