Conquering ammonium bisulfate poison over low-temperature NH3-SCR catalysts: A critical review

Guo, Kai; Ji, Jiawei; Wang, Song; Sun, Jingfang; Tang, Changjin; Dong, Lin

doi:10.1016/j.apcatb.2021.120388

Cited by 144 publications

(60 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ammonium sulfate ((NH 4 ) 2 SO 4 ; AS) and ammonium bisulfate ((NH 4 )HSO 4 ; ABS) are deemed as conventional yet omnipotent surface poisons to severely limit a SCR efficiency of a catalyst in the presence of SO 2 at ≤300 °C. , AS/ABS generation is initiated by oxidative transition of SO 2 to SO 3 , after which SO 3 reacts with H 2 O/NH 3 to generate AS/ABS (Figure C). − AS/ABS production is exothermic/spontaneous, thereby displaying thermodynamic equilibrium conversions ( X EQ ) of ∼100% at ≤300 °C (Table S2). SO A 2– -modified MnV 2 O 6 recently has unveiled an intriguing feature to degrade AS/ABS under low thermal energies .…”

Section: Introductionmentioning

confidence: 99%

Decrypting Catalytic NO_X Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO₃^2–/SO₄^2– Modifiers under a SO₂-Containing Flue Gas Stream

et al. 2022

View full text Add to dashboard Cite

SO A 2– (A = 3–4; B–) functionalities are anchored on metal oxides used to catalyze NH3-assisted selective NO X reduction (SCR) for a SO2-bearing feed gas stream. SO A 2– species act as conjugate bases of Brönsted acidic bonds (B––H+) and modifiers of redox sites (M(n–1)+–O–), both of which are combined to dictate the activities of SCR (−r NOX ) and ammonium (bi) sulfate (AS/ABS) poison degradation (−r AS/ABS) at low temperatures. Nonetheless, their pathways have been barely clarified and underexplored, while questioning catalytic significance of mono-dentate or bi-dentate SO A 2– species in dominating −r NOX and −r AS/ABS. While using Sb-promoted MnV2O6 as a reservoir of SO A 2– functionalities with distinct binding arrays, elementary stages for the SCR and AS/ABS degradation were proposed, thermodynamically assessed, and analyzed using kinetic control runs in tandem with density functional theory calculations. These allowed for the conclusions that the reaction stage between B––H+•••NH3•••O––M(n–1)+ and gaseous NO and the liberation stage of H2O/SO2 from B–•••H2O•••SO2•••H2O via dissociative desorption are endothermic and dominate −r NOX and −r AS/ABS as the rate-determining steps of the SCR and AS/ABS degradation, respectively. In addition, mono-dentate and bi-dentate SO A 2– species are verified central in directing −r NOX and −r AS/ABS by elevating collision frequency between B––H+•••NH3•••O––M(n–1)+ and NO and declining the energy barrier required for dissociative H2O/SO2 desorption for the SCR and AS/ABS degradation, respectively. In particular, mono-dentate SO A 2– functionalities can improve the overall redox trait of the surface, thereby substantially promoting its low-temperature SCR performance under a SO2-excluding feed gas stream. Meanwhile, bi-dentate SO A 2– functionalities can slightly improve the overall redox trait of the surface, yet, can readily degrade AS/ABS by accelerating the endothermic fragmentation of S2O7 2– innate to ammonium pyrosulfate, while compensating for the moderate efficiency in fragmenting NH4 + of ammonium pyrosulfate via Eley–Rideal-type SCR. This can significantly elevate the SCR performance of the bi-dentate SO A 2–-containing surface under a SO2-including feed gas stream alongside with the promotion of its long-term stability at low temperatures. These can be adaptable and exploited in discovering/amending a host of metal oxides (or vanadates) imperatively functionalized with SO A 2– or poisoned with AS/ABS under low thermal energies.

show abstract

Section: Introductionmentioning

confidence: 99%

Decrypting Catalytic NO_X Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO₃^2–/SO₄^2– Modifiers under a SO₂-Containing Flue Gas Stream

et al. 2022

View full text Add to dashboard Cite

show abstract

“…8d). [52][53][54] Meanwhile, the N 1s band at ∼401.3 eV was also observed on the CeWSnO x -800-300S catalyst (Fig. 8e).…”

Section: Catalysis Science and Technologymentioning

confidence: 82%

“…This result showed that the deposition of SO 4 2− -related species on the catalyst surface also triggered chemical alteration of W and Ce species. 54 The higher electron cloud density due to the strong interaction between W (or Sn) and SO 4 2− exerted a positive effect on the transformation of SO 4 2− to SO 2 during heat treatment, 56 and thus contributed to the decomposition of sulfates formed during the in situ SO 2 poisoning. After thermal regeneration treatments, the S 2p and N 1s signals disappeared (Fig.…”

Section: Resultsmentioning

confidence: 99%

Ceria–tungsten–tin oxide catalysts with superior regeneration capacity after sulfur poisoning for NH₃-SCR process

Liu

Shi

et al. 2022

Catal. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…It has been demonstrated that the formation of metal sulfates and the deposition of ammonium sulfates caused by SO 2 poisoning would greatly inhibit the adsorption and activation of NO x and NH 3 , which led to the severe catalyst deactivation. [11][12][13] To address this issue, reducing the SO 2 adsorption and activation, constructing sacrificial sites, and promoting sulfates decomposition are considered the most effective strategies to enhance the SO 2 resistance of SCR catalysts. 14 For instance, a novel HPMo/TiO 2 core-shell catalyst of copper-doped phosphomolybdic acid supported on titanium dioxide could be applied to partially block the adsorption of SO 2 , which indeed restrained the deposition of sulfates species and enhanced SO 2 tolerance.…”

Section: Introductionmentioning

confidence: 99%

SO₂-Tolerant catalytic reduction of NO_x by confining active species in TiO₂ nanotubes

Impeng

Jia

et al. 2022

Environ. Sci.: Nano

View full text Add to dashboard Cite

show abstract

Conquering ammonium bisulfate poison over low-temperature NH3-SCR catalysts: A critical review

Cited by 144 publications

References 62 publications

Decrypting Catalytic NO_X Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO₃^2–/SO₄^2– Modifiers under a SO₂-Containing Flue Gas Stream

Decrypting Catalytic NO_X Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO₃^2–/SO₄^2– Modifiers under a SO₂-Containing Flue Gas Stream

Ceria–tungsten–tin oxide catalysts with superior regeneration capacity after sulfur poisoning for NH₃-SCR process

SO₂-Tolerant catalytic reduction of NO_x by confining active species in TiO₂ nanotubes

Contact Info

Product

Resources

About

Conquering ammonium bisulfate poison over low-temperature NH3-SCR catalysts: A critical review

Cited by 144 publications

References 62 publications

Decrypting Catalytic NOX Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO32–/SO42– Modifiers under a SO2-Containing Flue Gas Stream

Decrypting Catalytic NOX Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO32–/SO42– Modifiers under a SO2-Containing Flue Gas Stream

Ceria–tungsten–tin oxide catalysts with superior regeneration capacity after sulfur poisoning for NH3-SCR process

SO2-Tolerant catalytic reduction of NOx by confining active species in TiO2 nanotubes

Contact Info

Product

Resources

About

Decrypting Catalytic NO_X Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO₃^2–/SO₄^2– Modifiers under a SO₂-Containing Flue Gas Stream

Decrypting Catalytic NO_X Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO₃^2–/SO₄^2– Modifiers under a SO₂-Containing Flue Gas Stream

Ceria–tungsten–tin oxide catalysts with superior regeneration capacity after sulfur poisoning for NH₃-SCR process

SO₂-Tolerant catalytic reduction of NO_x by confining active species in TiO₂ nanotubes