Molecular-Level Insight into Selective Catalytic Reduction of NOx with NH3 to N-2 over a Highly Efficient Bifunctional V-alpha-MnOx Catalyst at Low Temperature

Ying Xin, Hao Li, Nana Zhang, Qian Li, Zhaoliang Zhang, Xiaoming Cao, P. Hu, Lirong Zheng, James A. Anderson

Research output: Contribution to journalArticle

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Abstract

Selective catalytic reduction of NOx with ammonia (SCR) is not only an important model catalytic reaction but is also significant in terms of improving environmental air quality and human health. However, SCR catalysts suffer from low activity and selectivity to N-2 at low temperature, which in part may be attributed to our limited understanding of the reaction mechanism. Here, an unambiguous molecular-level mechanism is presented for an improved low-temperature SCR activity using bifunctional catalysts composed of highly active oxides (Mn2O3) for NH3 activation and highly selective vanadates (Mn2V2O7) that promote N-2 formation. NH3 is initially activated by Mn2O3 to form an NH2 intermediate. Transfer of NH2 to Mn2V2P7 then takes place, which facilitates the capture of gaseous NO leading to the formation of NH2NO over Mn2V2O7, whereafter NH2NO is efficiently converted to the preferred N-2 rather than the undesired byproduct, N2O. The proximity of the two components achieved via sol gel preparation plays a crucial role in the transfer of active intermediates.

Original languageEnglish
Pages (from-to)4937-4949
Number of pages25
JournalACS Catalysis
Volume8
Issue number6
Early online date23 Apr 2018
DOIs
Publication statusPublished - Jun 2018

Keywords

  • nitrogen oxides
  • selective catalytic reduction
  • bifunctional catalyst
  • density functional theory
  • mechanism
  • MANGANESE OXIDE CATALYSTS
  • TOTAL-ENERGY CALCULATIONS
  • TI AMORPHOUS OXIDES
  • WAVE BASIS-SET
  • ACTIVE-SITES
  • HYBRID CATALYSTS
  • NITRIC-OXIDE
  • MNOX-CEO2 CATALYST
  • REACTION-MECHANISM
  • SUPERIOR CATALYST

Cite this

Molecular-Level Insight into Selective Catalytic Reduction of NOx with NH3 to N-2 over a Highly Efficient Bifunctional V-alpha-MnOx Catalyst at Low Temperature. / Xin, Ying; Li, Hao; Zhang, Nana; Li, Qian; Zhang, Zhaoliang; Cao, Xiaoming; Hu, P.; Zheng, Lirong; Anderson, James A.

In: ACS Catalysis, Vol. 8, No. 6, 06.2018, p. 4937-4949.

Research output: Contribution to journalArticle

Xin, Ying ; Li, Hao ; Zhang, Nana ; Li, Qian ; Zhang, Zhaoliang ; Cao, Xiaoming ; Hu, P. ; Zheng, Lirong ; Anderson, James A. / Molecular-Level Insight into Selective Catalytic Reduction of NOx with NH3 to N-2 over a Highly Efficient Bifunctional V-alpha-MnOx Catalyst at Low Temperature. In: ACS Catalysis. 2018 ; Vol. 8, No. 6. pp. 4937-4949.
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abstract = "Selective catalytic reduction of NOx with ammonia (SCR) is not only an important model catalytic reaction but is also significant in terms of improving environmental air quality and human health. However, SCR catalysts suffer from low activity and selectivity to N-2 at low temperature, which in part may be attributed to our limited understanding of the reaction mechanism. Here, an unambiguous molecular-level mechanism is presented for an improved low-temperature SCR activity using bifunctional catalysts composed of highly active oxides (Mn2O3) for NH3 activation and highly selective vanadates (Mn2V2O7) that promote N-2 formation. NH3 is initially activated by Mn2O3 to form an NH2 intermediate. Transfer of NH2 to Mn2V2P7 then takes place, which facilitates the capture of gaseous NO leading to the formation of NH2NO over Mn2V2O7, whereafter NH2NO is efficiently converted to the preferred N-2 rather than the undesired byproduct, N2O. The proximity of the two components achieved via sol gel preparation plays a crucial role in the transfer of active intermediates.",
keywords = "nitrogen oxides, selective catalytic reduction, bifunctional catalyst, density functional theory, mechanism, MANGANESE OXIDE CATALYSTS, TOTAL-ENERGY CALCULATIONS, TI AMORPHOUS OXIDES, WAVE BASIS-SET, ACTIVE-SITES, HYBRID CATALYSTS, NITRIC-OXIDE, MNOX-CEO2 CATALYST, REACTION-MECHANISM, SUPERIOR CATALYST",
author = "Ying Xin and Hao Li and Nana Zhang and Qian Li and Zhaoliang Zhang and Xiaoming Cao and P. Hu and Lirong Zheng and Anderson, {James A.}",
note = "This work was supported by the National Natural Science Foundation of China (Nos. 21477046, 21333003, and 21673072) and Key Technology R&D Program of Shandong Province (No. 2016ZDJS11A03). The authors also acknowledge computing time support from the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (the second phase) under Grant No. U1501501.",
year = "2018",
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T1 - Molecular-Level Insight into Selective Catalytic Reduction of NOx with NH3 to N-2 over a Highly Efficient Bifunctional V-alpha-MnOx Catalyst at Low Temperature

AU - Xin, Ying

AU - Li, Hao

AU - Zhang, Nana

AU - Li, Qian

AU - Zhang, Zhaoliang

AU - Cao, Xiaoming

AU - Hu, P.

AU - Zheng, Lirong

AU - Anderson, James A.

N1 - This work was supported by the National Natural Science Foundation of China (Nos. 21477046, 21333003, and 21673072) and Key Technology R&D Program of Shandong Province (No. 2016ZDJS11A03). The authors also acknowledge computing time support from the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (the second phase) under Grant No. U1501501.

PY - 2018/6

Y1 - 2018/6

N2 - Selective catalytic reduction of NOx with ammonia (SCR) is not only an important model catalytic reaction but is also significant in terms of improving environmental air quality and human health. However, SCR catalysts suffer from low activity and selectivity to N-2 at low temperature, which in part may be attributed to our limited understanding of the reaction mechanism. Here, an unambiguous molecular-level mechanism is presented for an improved low-temperature SCR activity using bifunctional catalysts composed of highly active oxides (Mn2O3) for NH3 activation and highly selective vanadates (Mn2V2O7) that promote N-2 formation. NH3 is initially activated by Mn2O3 to form an NH2 intermediate. Transfer of NH2 to Mn2V2P7 then takes place, which facilitates the capture of gaseous NO leading to the formation of NH2NO over Mn2V2O7, whereafter NH2NO is efficiently converted to the preferred N-2 rather than the undesired byproduct, N2O. The proximity of the two components achieved via sol gel preparation plays a crucial role in the transfer of active intermediates.

AB - Selective catalytic reduction of NOx with ammonia (SCR) is not only an important model catalytic reaction but is also significant in terms of improving environmental air quality and human health. However, SCR catalysts suffer from low activity and selectivity to N-2 at low temperature, which in part may be attributed to our limited understanding of the reaction mechanism. Here, an unambiguous molecular-level mechanism is presented for an improved low-temperature SCR activity using bifunctional catalysts composed of highly active oxides (Mn2O3) for NH3 activation and highly selective vanadates (Mn2V2O7) that promote N-2 formation. NH3 is initially activated by Mn2O3 to form an NH2 intermediate. Transfer of NH2 to Mn2V2P7 then takes place, which facilitates the capture of gaseous NO leading to the formation of NH2NO over Mn2V2O7, whereafter NH2NO is efficiently converted to the preferred N-2 rather than the undesired byproduct, N2O. The proximity of the two components achieved via sol gel preparation plays a crucial role in the transfer of active intermediates.

KW - nitrogen oxides

KW - selective catalytic reduction

KW - bifunctional catalyst

KW - density functional theory

KW - mechanism

KW - MANGANESE OXIDE CATALYSTS

KW - TOTAL-ENERGY CALCULATIONS

KW - TI AMORPHOUS OXIDES

KW - WAVE BASIS-SET

KW - ACTIVE-SITES

KW - HYBRID CATALYSTS

KW - NITRIC-OXIDE

KW - MNOX-CEO2 CATALYST

KW - REACTION-MECHANISM

KW - SUPERIOR CATALYST

U2 - 10.1021/acscatal.8b00196

DO - 10.1021/acscatal.8b00196

M3 - Article

VL - 8

SP - 4937

EP - 4949

JO - ACS Catalysis

JF - ACS Catalysis

SN - 2155-5435

IS - 6

ER -