Promoting Effect of Basic Metal Additives on DeNOx Reactions over Pt-Based Three-Way Catalysts
Promoting Effect of Basic Metal Additives on DeNOx Reactions over Pt-Based Three-Way Catalysts
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DOI：
10.1016/j.jcat.2022.10.018
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发表时间：
2022-11
影响因子：
7.3
通讯作者：
Yuan Jing;Gang Wang;Shinya Mine;Jumpei Kawai;R. Toyoshima;H. Kondoh;Xiaorui Zhang;Shuhei Nagaoka;K. Shimizu;Takashi Toyao
中科院分区：
文献类型：
--
作者：
Yuan Jing;Gang Wang;Shinya Mine;Jumpei Kawai;R. Toyoshima;H. Kondoh;Xiaorui Zhang;Shuhei Nagaoka;K. Shimizu;Takashi Toyao
Pt在经济上优于Rh和Pd。然而，基于Pt的三效催化剂（TWC）的研究少于基于Pd和Rh的TWC;因此，它们的性质尚未得到充分评价，特别是在与现代三效催化操作相关的条件下，其中经常遇到偏离化学计量条件的情况。在这项研究中，我们研究了在Pt/M/Al_2 O_3（M = Ba，La，Sr）的三效催化反应的效率的碱性金属添加剂的促进作用。Pt/M/Al 2 O3催化剂对NO、CO和总烃的催化活性均上级Pt/Al 2 O3;此外，Ba比La和Sr更有效地提高了Pt基催化剂的催化活性。对性能最好的催化剂Pt/Ba/Al 2 O3进行了动力学研究和各种原位/操作光谱实验，即X射线吸收光谱，红外光谱，和常压X射线光电子能谱（AP-XPS）研究Ba在NO还原反应中的作用。AP-XPS结果表明，Pt 0在Ba/Al 2 O3上的电子富集程度高于在Al 2 O3上，从而促进了NO分解为N和O原子.此外，中间表面NOx物种的有效形成，包括亚硝酸盐和硝酸盐，以及它们对还原性气体，如H2或CO的反应性，是促进Ba对NO还原反应的影响的关键。
Pt has been economically favored over Rh and Pd. However, Pt-based three-way catalysts (TWCs) have been studied less than Pd- and Rh-based TWCs; therefore, their properties have not yet been sufficiently evaluated, especially under conditions relevant to modern three-way catalysis operation, wherein deviations from stoichiometric conditions are often encountered. In this study, we examined the promotional effect of basic metal additives in Pt/M/Al2O3(M = Ba, La, Sr) on the efficiency of three-way catalytic reactions. The catalytic activities of the Pt/M/Al2O3catalysts for NO, CO, and total hydrocarbons were superior to those of Pt/Al2O3; moreover, Ba enhanced the catalytic activity of Pt-based catalysts more efficiently than La and Sr. The best-performing catalyst, Pt/Ba/Al2O3, was subjected to kinetic studies and variousin situ/operandospectroscopic experiments, namely, X-ray absorption spectroscopy, infrared spectroscopy, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), to investigate the role of Ba in the NO reduction reaction. The Pt0species loaded on Ba/Al2O3were more electron-rich than those loaded on Al2O3, thereby promoting NO dissociation into N and O atoms, as revealed by the AP-XPS results. Moreover, the efficient formation of intermediate surface NOxspecies, including nitrites and nitrates, and their reactivities toward reductant gases, such as H2or CO, were critical for promoting the effect of Ba on the NO reduction reaction.