Boosting SO₂-Resistant NO_x Reduction by Modulating Electronic Interaction of Short-Range Fe–O Coordination over Fe₂O₃/TiO₂ Catalysts

Abstract

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 sulfurdoped 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 42− 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.

Promoting effect ofN2calcination onFeCeOxfor selective catalytic reduction ofNOxwithNH3

“…20,21 Liu et al boosted SO 2 -resistant NO x reduction by modulating the electronic interaction of short-range Fe−O coordination over Fe 2 O 3 /TiO 2 catalysts. 22 After doping with a second metal, the catalytic performance of the catalysts always improved significantly. 23 Because of its good oxygen storage and redox ability, Ce could be added to the catalyst preparation process as a promoter.…”

“…Liu et al . boosted SO 2 ‐resistant NO x reduction by modulating the electronic interaction of short‐range Fe−O coordination over Fe 2 O 3 /TiO 2 catalysts 22 . After doping with a second metal, the catalytic performance of the catalysts always improved significantly 23 .…”

SO2-resistant NOx reduction over Cu-SAPO-34 catalysts via creating sulfur-phobic Cu sites

“…Selective catalytic reduction of NO x by NH 3 (NH 3 -SCR) is one of the most effective technologies for purifying NO x at present. [7][8][9][10][11][12] The commercial Cu-SAPO-34 catalysts exhibit ultra-high activity, durability and hydrothermal stability in the after-treatment of automobile exhaust gas. 13,14 However, the presence of H 2 O and SO 2 in the tail gas causes deactivation of Cu-exchanged chabazite (Cu-CHA) catalysts, thereby greatly reducing the life of catalysts.…”

Continuous NO Upcycling into Ammonia Promoted by SO2 in Flue Gas: Poison Can Be a Gift

“…Because NO is produced from fossil fuel combustion, one should note that multicomponent air pollutants inevitably coexist with NO in the flue gas, in which sulfur dioxide (SO 2 ) is generally recognized as the main coexisting species with NO. − Hence, the effect of SO 2 poison on the development of the NORR route should be comprehensively investigated, which drives the research of NO conversion in a more sustainable manner . In our previous work, a coupled absorption–photoreduction system is developed, where the introduction of the Fe­(II) ethylenediaminetetraacetic acid [Fe­(II)­EDTA] complex is beneficial for NO absorption, which increases the concentration of the soluble NO reactant for continuous NO reduction .…”