Insights into the co-doping effect of Fe3+ and Zr4+ on the anti-K performance of CeTiOx catalyst for NH3-SCR reaction

Keke Kang; Xiaojiang Yao; Yike Huang; Jun Cao; Jing Rong; Wanxia Zhao; Wen Luo; Yang Chen

doi:10.1016/j.jhazmat.2021.125821

Insights into the co-doping effect of Fe³⁺ and Zr⁴⁺ on the anti-K performance of CeTiO_x catalyst for NH₃-SCR reaction

J Hazard Mater. 2021 Aug 15:416:125821. doi: 10.1016/j.jhazmat.2021.125821. Epub 2021 Apr 8.

Authors

Keke Kang¹, Xiaojiang Yao², Yike Huang³, Jun Cao⁴, Jing Rong⁴, Wanxia Zhao⁴, Wen Luo¹, Yang Chen¹

Affiliations

¹ Research Center for Atmospheric Environment, Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, PR China; College of Resources and Environment, Chongqing School, University of Chinese Academy of Sciences (UCAS Chongqing), Chongqing 400714, PR China; School of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China.
² Research Center for Atmospheric Environment, Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, PR China; College of Resources and Environment, Chongqing School, University of Chinese Academy of Sciences (UCAS Chongqing), Chongqing 400714, PR China; School of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China. Electronic address: yaoxj@cigit.ac.cn.
³ School of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China; CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.
⁴ Research Center for Atmospheric Environment, Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, PR China; College of Resources and Environment, Chongqing School, University of Chinese Academy of Sciences (UCAS Chongqing), Chongqing 400714, PR China.

PMID: 33866288
DOI: 10.1016/j.jhazmat.2021.125821

Abstract

A novel K-resistant Fe³⁺ and Zr⁴⁺ co-doped CeTiO_x catalyst was first prepared by co-precipitation method for the ammonia-selective catalytic reduction (NH₃-SCR) of NO_x. On the premise of retaining the outstanding catalytic activity of CeTiO_x catalyst, Fe³⁺ and Zr⁴⁺ co-doping efficiently improves its K-resistance with superior NO_x conversion up to 84% after K-poisoning. Specially, the grain growth during the second calcination after K poisoning is successfully inhibited by Fe³⁺ and Zr⁴⁺ co-doping. Consequently, the large specific surface area with increased acid sites and efficiently retained reducibility over K-poisoned FeZrCeTiO_x catalyst are realized, which prompt NH₃ activation and NO oxidation, further benefit NH₃-SCR. Besides, NH₃-SCR reaction over CeTiO_x and FeZrCeTiO_x catalysts follows a possible L-H mechanism, and K-poisoning makes no change to it. Finally, a reasonable anti-K poisoning mechanism of FeZrCeTiO_x catalyst is proposed: the excellent K-resistance is attributed to part of Fe and Zr are sacrificed to form Fe-O-K and Zr-O-K species protecting the active site Ce-O-Ti from K-poisoning, as well as the additional reducibility and surface acidity brought from Fe-O species with Zr prompting its uniform distribution.

Keywords: CeTiO(x) catalyst; Co-doping; K resistant; NH(3)-SCR reaction.