Unraveling the poisoning effects of different lead species on MnCeOx catalysts in low-temperature NH3-SCR coupled with CO oxidation

Shan Ren; Xiaodi Li; Manyi Liu; Liang Wang; Guangwei Wang; Wenxue Wang; Yifan Chai; Chunbao Charles Xu

doi:10.1016/j.cej.2026.178596

Unraveling the poisoning effects of different lead species on MnCeO_x catalysts in low-temperature NH₃-SCR coupled with CO oxidation

Shan Ren^* (Co-first Author)
, Xiaodi Li (Co-first Author)
, Manyi Liu
, Liang Wang
, Guangwei Wang
, Wenxue Wang
, Yifan Chai
, Chunbao Charles Xu

^*Corresponding author for this work

School of Energy and Environment

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

Abstract

Lead poisoning represents a major limitation for MnCeO_x catalyst used in low-temperature flue gas treatment. In this work, the effects of different Pb species on the physicochemical properties, catalytic performance, and reaction pathways of MnCeO_x catalyst were systematically investigated for the simultaneous removal of NO and CO. The catalytic performance results demonstrated that the poisoning severity strongly depended on Pb speciation, following the order of PbCl₂ > PbSO₄ > Pb(NO₃)₂ > PbCO₃. Although Pb deposition exerted little influence on the crystal structure of MnCeO_x, it induced notable changes in surface texture and electronic structure, leading to distinct deactivation behaviors. PbCl₂ caused the most severe loss of catalytic activity owing to extensive pore blockage, active site coverage, suppression of surface acidity, and deterioration of redox properties. In contrast, PbCO₃ exhibited the weakest poisoning effect and preserved relatively favorable surface characteristics. XPS and Raman analyses further demonstrated that Pb species decreased the surface Mn⁴⁺ concentration and hindered the Ce⁴⁺/Ce³⁺ redox cycle, leading to reduced oxygen vacancy density and impaired oxygen mobility. In situ DRIFTS analysis revealed that Pb species significantly altered surface reaction pathways. PbCO₃ maintained effective NO oxidation and NH₃ adsorption, enabling a nitrate mediated L-H route for NH₃-SCR, whereas PbCl₂ and PbSO₄ markedly suppressed nitrate formation and NH₃ activation, favoring a less efficient E-R pathway. In addition, Pb species modified carbonate formation and oxygen participation during CO oxidation reaction, leading to distinct oxidation behaviors among the poisoned catalysts. These results provided mechanistic insights into Pb poisoning and offer a guidance for the rational design of Pb-tolerant MnCeO_x catalysts for low-temperature flue gas purification. © 2026 Elsevier B.V.

Original language	English
Article number	178596
Journal	Chemical Engineering Journal
Volume	543
Online published	19 Jun 2026
DOIs	https://doi.org/10.1016/j.cej.2026.178596
Publication status	Published - 1 Sept 2026

Funding

This work was financially supported by the National Natural Science Foundation of China (No. 52374411), the Outstanding Youth Science Foundation of Shaanxi Province (No. 2025JC-JCQN-031), the Inner Mongolia Autonomous Region Science and Technology Planning Project (No. 2025YFHH0055), and the Key Research and Development Program Project of Shaanxi Province (No. 2025CY-GJHX2-12).

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Research Keywords

CO oxidation
MnCeOx catalysts
NH3-SCR
Pb poisoning
Reaction mechanism

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@article{43985d7e1ab94dbe84560a164a5ac4f3,

title = "Unraveling the poisoning effects of different lead species on MnCeOx catalysts in low-temperature NH3-SCR coupled with CO oxidation",

abstract = "Lead poisoning represents a major limitation for MnCeOx catalyst used in low-temperature flue gas treatment. In this work, the effects of different Pb species on the physicochemical properties, catalytic performance, and reaction pathways of MnCeOx catalyst were systematically investigated for the simultaneous removal of NO and CO. The catalytic performance results demonstrated that the poisoning severity strongly depended on Pb speciation, following the order of PbCl2 > PbSO4 > Pb(NO3)2 > PbCO3. Although Pb deposition exerted little influence on the crystal structure of MnCeOx, it induced notable changes in surface texture and electronic structure, leading to distinct deactivation behaviors. PbCl2 caused the most severe loss of catalytic activity owing to extensive pore blockage, active site coverage, suppression of surface acidity, and deterioration of redox properties. In contrast, PbCO3 exhibited the weakest poisoning effect and preserved relatively favorable surface characteristics. XPS and Raman analyses further demonstrated that Pb species decreased the surface Mn4+ concentration and hindered the Ce4+/Ce3+ redox cycle, leading to reduced oxygen vacancy density and impaired oxygen mobility. In situ DRIFTS analysis revealed that Pb species significantly altered surface reaction pathways. PbCO3 maintained effective NO oxidation and NH3 adsorption, enabling a nitrate mediated L-H route for NH3-SCR, whereas PbCl2 and PbSO4 markedly suppressed nitrate formation and NH3 activation, favoring a less efficient E-R pathway. In addition, Pb species modified carbonate formation and oxygen participation during CO oxidation reaction, leading to distinct oxidation behaviors among the poisoned catalysts. These results provided mechanistic insights into Pb poisoning and offer a guidance for the rational design of Pb-tolerant MnCeOx catalysts for low-temperature flue gas purification. {\textcopyright} 2026 Elsevier B.V.",

keywords = "CO oxidation, MnCeOx catalysts, NH3-SCR, Pb poisoning, Reaction mechanism",

author = "Shan Ren and Xiaodi Li and Manyi Liu and Liang Wang and Guangwei Wang and Wenxue Wang and Yifan Chai and Xu, \{Chunbao Charles\}",

year = "2026",

month = sep,

day = "1",

doi = "10.1016/j.cej.2026.178596",

language = "English",

volume = "543",

journal = "Chemical Engineering Journal",

issn = "1385-8947",

publisher = "Elsevier B.V.",

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Unraveling the poisoning effects of different lead species on MnCeO_x catalysts in low-temperature NH₃-SCR coupled with CO oxidation. / Ren, Shan (Co-first Author); Li, Xiaodi (Co-first Author); Liu, Manyi et al.
In: Chemical Engineering Journal, Vol. 543, 178596, 01.09.2026.

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

TY - JOUR

T1 - Unraveling the poisoning effects of different lead species on MnCeOx catalysts in low-temperature NH3-SCR coupled with CO oxidation

AU - Ren, Shan

AU - Li, Xiaodi

AU - Liu, Manyi

AU - Wang, Liang

AU - Wang, Guangwei

AU - Wang, Wenxue

AU - Chai, Yifan

AU - Xu, Chunbao Charles

PY - 2026/9/1

Y1 - 2026/9/1

N2 - Lead poisoning represents a major limitation for MnCeOx catalyst used in low-temperature flue gas treatment. In this work, the effects of different Pb species on the physicochemical properties, catalytic performance, and reaction pathways of MnCeOx catalyst were systematically investigated for the simultaneous removal of NO and CO. The catalytic performance results demonstrated that the poisoning severity strongly depended on Pb speciation, following the order of PbCl2 > PbSO4 > Pb(NO3)2 > PbCO3. Although Pb deposition exerted little influence on the crystal structure of MnCeOx, it induced notable changes in surface texture and electronic structure, leading to distinct deactivation behaviors. PbCl2 caused the most severe loss of catalytic activity owing to extensive pore blockage, active site coverage, suppression of surface acidity, and deterioration of redox properties. In contrast, PbCO3 exhibited the weakest poisoning effect and preserved relatively favorable surface characteristics. XPS and Raman analyses further demonstrated that Pb species decreased the surface Mn4+ concentration and hindered the Ce4+/Ce3+ redox cycle, leading to reduced oxygen vacancy density and impaired oxygen mobility. In situ DRIFTS analysis revealed that Pb species significantly altered surface reaction pathways. PbCO3 maintained effective NO oxidation and NH3 adsorption, enabling a nitrate mediated L-H route for NH3-SCR, whereas PbCl2 and PbSO4 markedly suppressed nitrate formation and NH3 activation, favoring a less efficient E-R pathway. In addition, Pb species modified carbonate formation and oxygen participation during CO oxidation reaction, leading to distinct oxidation behaviors among the poisoned catalysts. These results provided mechanistic insights into Pb poisoning and offer a guidance for the rational design of Pb-tolerant MnCeOx catalysts for low-temperature flue gas purification. © 2026 Elsevier B.V.

AB - Lead poisoning represents a major limitation for MnCeOx catalyst used in low-temperature flue gas treatment. In this work, the effects of different Pb species on the physicochemical properties, catalytic performance, and reaction pathways of MnCeOx catalyst were systematically investigated for the simultaneous removal of NO and CO. The catalytic performance results demonstrated that the poisoning severity strongly depended on Pb speciation, following the order of PbCl2 > PbSO4 > Pb(NO3)2 > PbCO3. Although Pb deposition exerted little influence on the crystal structure of MnCeOx, it induced notable changes in surface texture and electronic structure, leading to distinct deactivation behaviors. PbCl2 caused the most severe loss of catalytic activity owing to extensive pore blockage, active site coverage, suppression of surface acidity, and deterioration of redox properties. In contrast, PbCO3 exhibited the weakest poisoning effect and preserved relatively favorable surface characteristics. XPS and Raman analyses further demonstrated that Pb species decreased the surface Mn4+ concentration and hindered the Ce4+/Ce3+ redox cycle, leading to reduced oxygen vacancy density and impaired oxygen mobility. In situ DRIFTS analysis revealed that Pb species significantly altered surface reaction pathways. PbCO3 maintained effective NO oxidation and NH3 adsorption, enabling a nitrate mediated L-H route for NH3-SCR, whereas PbCl2 and PbSO4 markedly suppressed nitrate formation and NH3 activation, favoring a less efficient E-R pathway. In addition, Pb species modified carbonate formation and oxygen participation during CO oxidation reaction, leading to distinct oxidation behaviors among the poisoned catalysts. These results provided mechanistic insights into Pb poisoning and offer a guidance for the rational design of Pb-tolerant MnCeOx catalysts for low-temperature flue gas purification. © 2026 Elsevier B.V.

KW - CO oxidation

KW - MnCeOx catalysts

KW - NH3-SCR

KW - Pb poisoning

KW - Reaction mechanism

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