Promotion effect and mechanism of the addition of Mo on the enhanced low temperature SCR of NOx by NH3 over MnOx/Γ-Al2O3 catalysts

Gang Yang, Haitao Zhao, Xiang Luo, Kaiqi Shi, Haibao Zhao, Wenkai Wang, Quhan Chen, Hua Fan, Tao Wu

Research output: Journal PublicationArticlepeer-review

69 Citations (Scopus)
2 Downloads (Pure)

Abstract

A series of Mn/γ-Al2O3 and MnxMoy/γ-Al2O3 catalysts were prepared by using Incipient Wetness Impregnation (IWI) method. The catalytic performance tests showed that the Mn3Mo1.25/γ-Al2O3 demonstrated a higher SCR performance (NO conversion of around 96%) at a broad low temperature range (150–300 °C). The characterization showed that the addition of Mo to the Mn/γ-Al2O3 catalysts promoted the dispersion of MnOx on the surface of γ-Al2O3. The adsorption of NO could form two different species, i.e., nitrites and nitrates, on the surface of the catalyst. The presence of nitrites is beneficial to low temperature SCR. It is found that the existence of Mo in the catalyst favours the formation of Mn3+, which plays a critical role in the adsorption of NH3 and therefore improves NH3 adsorption capacity of the MnOx/γ-Al2O3 catalysts. The low temperature SCR of the Mn3Mo1.25/γ-Al2O3 catalyst was found to mainly follow L-H mechanism, but E-R mechanism also plays a role to some extent. Moreover, it is found that the addition of Mo not only mitigates the deactivation of the catalysts, but also broadens the effective temperature range of the SCR catalysts.

Original languageEnglish
Pages (from-to)743-752
Number of pages10
JournalApplied Catalysis B: Environmental
Volume245
DOIs
Publication statusPublished - 15 May 2019

Keywords

  • Low temperature SCR
  • Mechanism
  • MnMo/γ-AlO
  • Mo addition
  • Promotion effects

ASJC Scopus subject areas

  • Catalysis
  • Environmental Science (all)
  • Process Chemistry and Technology

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