Zhang Peng, Mei Xuelei, Zhao Xiaochan, Xiong Jing, Li Yuanfeng, Zhao Zhen, Wei Yuechang
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China.
Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing 102249, P. R. China.
Environ Sci Technol. 2021 Aug 17;55(16):11245-11254. doi: 10.1021/acs.est.1c01781. Epub 2021 Aug 2.
The catalytic performances for soot purification over the perovskite-type ABO oxides, as one of the most potential non-noble metal catalysts, are closely correlated with the substitution of A-site and B-site ions. Herein, three-dimensional ordered macroporous (3DOM) structural catalysts of double perovskite-type LaKNiCoO were prepared by a method of colloidal crystal template. The contact efficiency between the catalyst and soot particles is significantly promoted by the 3DOM structure, and the partial substitution of A-site (La) with low-valence potassium (K) ions in LaKNiCoO catalysts boosts the increasing surface density of coordinatively unsaturated active B-sites (Co and Ni) and active oxygen. 3DOM LaKNiCoO catalysts exhibited superior performance during the purification of soot particles, and the 3DOM LaKNiCoO catalyst exhibited the highest activity, that is, the values of , , and turnover frequency are 346 °C, 99.3%, and 0.204 h (at 300 °C), respectively. According to the results of multiple experimental characterizations and density functional theory calculations, the mechanism of the samples during soot removal is proposed: the increase in surface oxygen density induced by the doping of K ions significantly promotes the critical step of the oxidation from NO to NO in catalyzing soot purification. It is one new strategy to develop the high-efficient non-noble metal catalysts for soot purification in practical application.
作为最具潜力的非贵金属催化剂之一，钙钛矿型ABO氧化物对碳烟净化的催化性能与A位和B位离子的取代密切相关。在此，采用胶体晶体模板法制备了双钙钛矿型LaKNiCoO的三维有序大孔（3DOM）结构催化剂。3DOM结构显著提高了催化剂与碳烟颗粒之间的接触效率，并且LaKNiCoO催化剂中低价钾（K）离子对A位（La）的部分取代提高了配位不饱和活性B位（Co和Ni）和活性氧的表面密度。3DOM LaKNiCoO催化剂在碳烟颗粒净化过程中表现出优异的性能，其中3DOM LaKNiCoO催化剂活性最高，即T10、T90和周转频率的值分别为346℃、99.3%和0.204 h-1（在300℃下）。根据多种实验表征和密度泛函理论计算结果，提出了样品在碳烟去除过程中的作用机制：K离子掺杂引起的表面氧密度增加显著促进了催化碳烟净化过程中NO氧化为NO2的关键步骤。这是在实际应用中开发高效非贵金属碳烟净化催化剂的一种新策略。
