OPEN ACCESS

Articles online

In Situ DRIFTS Study of the Low Temperature Selective Catalytic Reduction of NO with NH3 over MnOx Supported on Multi-Walled Carbon Nanotubes Catalysts

Category: Control Techniques and Strategy

Volume: 15 | Issue: 3 | Pages: 1017-1027
DOI: 10.4209/aaqr.2014.08.0162
PDF | RIS | BibTeX

Chenglong Yu1, Lishan Wang1, Bichun Huang 1,2

  • 1 College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
  • 2 Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters (South China University of Technology), Ministry of Education, Guangzhou 510006, China

Highlights

NH4+ was more active than coordinate NH3 over the catalysts in SCR process.
NOx adsorption was more prominent than ammonia over the catalysts.
There were two possible pathways existing in SCR reaction over the catalysts.


Abstract

MnOx supported on multi-walled carbon nanotubes (MWCNTs) catalysts were prepared by the pore volume impregnation method and used for low-temperature selective catalytic reduction (SCR) of NO with NH3. Based on the previous study, 10 wt.% loading MnOx/MWCNTs were then selected for investigation of the reaction mechanism by in situ Diffuse Reflectance Infrared Fourier Transform spectroscopy (in-situ DRIFTS). The important intermediates in the SCR of NOx process at 210°C were discussed based on the DRIFTS results. Furthermore, the NH3-SCR reaction pathways over MnOx/MWCNTs catalysts were proposed. The results showed that NH4+ species on Brønsted acid sites and coordinate ammonia species on Lewis acid sites existed during the SCR reaction. NH4+ species was more active than coordinate ammonia species over the catalysts at 210°C. Most of NOx ad-species would react with NH3 ad-species. However, nitrite species, bidentate and monodentate nitrates contributed to the SCR reaction over the catalysts mostly. Two possible reaction pathways were proposed. One was that NOx ad-species could react with NH4+ to form intermediate of NH4N2O4 (a), NH4NO2 (a) or NH4NO3 (a), then to produce N2 and H2O as the final products. The other pathway was that NH3 was initially adsorbed on active site and NH2 was formed, then NH2 reacted with NOx ad-species to produce intermediate NH2NO2 or NH2NO3 which were unstable and would decompose into N2 and H2O.

Keywords

Low-temperature SCR MnOx/MWCNTs In-situ DRIFTS Reaction pathways


Related Article

Improved Photocatalytic Air Cleaner with Decomposition of Aldehyde and Aerosol-Associated Influenza Virus Infectivity in Indoor Air

Kimiyasu Shiraki , Hiroshi Yamada, Yoshihiro Yoshida, Ayumu Ohno, Teruo Watanabe, Takafumi Watanabe, Hiroyuki Watanabe, Hidemitsu Watanabe, Masao Yamaguchi, Fumio Tokuoka, Shigeatsu Hashimoto, Masakazu Kawamura, Norihisa Adachi
Volume: 17 | Issue: 11 | Pages: 2901-2912
DOI: 10.4209/aaqr.2017.06.0220
PDF

High Selectivity of Visible-Light-Driven La-doped TiO2 Photocatalysts for NO Removal

Yu Huang, Jun-Ji Cao, Fei Kang, Sheng-Jie You, Chia-Wei Chang, Ya-Fen Wang
Volume: 17 | Issue: 10 | Pages: 2555-2565
DOI: 10.4209/aaqr.2017.08.0282
PDF

Laboratory Evaluation of a Manure Additive for Mitigating Gas and Odor Releases from Layer Hen Manure

Ji-Qin Ni , Albert J. Heber, Teng T. Lim, Sam M. Hanni, Claude A. Diehl
Volume: 17 | Issue: 10 | Pages: 2533-2541
DOI: 10.4209/aaqr.2016.07.0327
PDF
;