Kang Keke, Yao Xiaojiang, Huang Yike, Cao Jun, Rong Jing, Zhao Wanxia, Luo Wen, Chen Yang
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.
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.
J Hazard Mater. 2021 Aug 15;416:125821. doi: 10.1016/j.jhazmat.2021.125821. Epub 2021 Apr 8.
A novel K-resistant Fe and Zr co-doped CeTiO catalyst was first prepared by co-precipitation method for the ammonia-selective catalytic reduction (NH-SCR) of NO. On the premise of retaining the outstanding catalytic activity of CeTiO catalyst, Fe and Zr co-doping efficiently improves its K-resistance with superior NO conversion up to 84% after K-poisoning. Specially, the grain growth during the second calcination after K poisoning is successfully inhibited by Fe and Zr co-doping. Consequently, the large specific surface area with increased acid sites and efficiently retained reducibility over K-poisoned FeZrCeTiO catalyst are realized, which prompt NH activation and NO oxidation, further benefit NH-SCR. Besides, NH-SCR reaction over CeTiO and FeZrCeTiO catalysts follows a possible L-H mechanism, and K-poisoning makes no change to it. Finally, a reasonable anti-K poisoning mechanism of FeZrCeTiO 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.
首次采用共沉淀法制备了一种新型的抗钾铁锆共掺杂CeTiO催化剂，用于氨选择性催化还原（NH-SCR）NO。在保留CeTiO催化剂优异催化活性的前提下，铁锆共掺杂有效提高了其抗钾性能，钾中毒后NO转化率高达84%。特别地，铁锆共掺杂成功抑制了钾中毒后二次煅烧过程中的晶粒生长。因此，在钾中毒的FeZrCeTiO催化剂上实现了具有增加的酸性位点和有效保留的还原性的大比表面积，这促进了NH的活化和NO的氧化，进一步有利于NH-SCR。此外，CeTiO和FeZrCeTiO催化剂上的NH-SCR反应遵循可能的L-H机理，钾中毒对其没有影响。最后，提出了FeZrCeTiO催化剂合理的抗钾中毒机理：优异的抗钾性能归因于部分铁和锆被牺牲形成Fe-O-K和Zr-O-K物种，保护活性位点Ce-O-Ti免受钾中毒，以及Fe-O物种与锆带来的额外还原性和表面酸性促使其均匀分布。
