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

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