Yang Li, Hu Jingnan, Tian Gang, Zhu Jinwei, Song Qiang, Wang Hongchang, Zhang Chen
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China.
Center for Durability & Sustainability Studies of Shandong Province, Qingdao University of Technology, Qingdao 266033, China.
ACS Omega. 2021 Jul 21;6(30):19836-19845. doi: 10.1021/acsomega.1c02565. eCollection 2021 Aug 3.
Presently, the treatment of four-way catalysts is important for reducing pollutant emissions from diesel engine exhaust, which is a major cause of urban haze. In this study, we prepared perovskite-type catalysts via the citric acid sol-gel method. Experiment results showed that K substitution at site A in LaMnO decreased the agglomeration of the catalysts effectively, increased the contact with the reaction gas, promoted the conversion of Mn → Mn, and reduced the ignition temperature of soot. Ce substitution at the B-site in LaKMnO produced a CeO phase and decreased the Mn/Mn ratio to 0.49, which is conducive to improving the catalytic oxidation performance. The K and Ce co-doping had the best activation effect, which showed a low activation energy (10.87 KJ mol) and a high simultaneous removal rate of NO (reaching 90% at 275 °C) and soot ignition at 250 °C under lean conditions.
目前，四效催化剂的处理对于减少柴油发动机尾气中的污染物排放至关重要，而柴油发动机尾气是城市雾霾的主要成因。在本研究中，我们通过柠檬酸溶胶-凝胶法制备了钙钛矿型催化剂。实验结果表明，LaMnO中A位的K取代有效地减少了催化剂的团聚，增加了与反应气体的接触，促进了Mn→Mn的转化，并降低了碳烟的着火温度。LaKMnO中B位的Ce取代产生了CeO相，并将Mn/Mn比降低至0.49，这有利于提高催化氧化性能。K和Ce共掺杂具有最佳的活化效果，其活化能较低（10.87 KJ/mol），在贫燃条件下，NO的同时去除率较高（在275℃时达到90%），且碳烟在250℃着火。
