文献类型：期刊文献

英文题名：The existing states of potassium species in K-doped Co3O4 catalysts and their influence on the activities for NO and soot oxidation

作者：Shang, Zhou;Sun, Min;Che, Xiang;Wang, Wei;Wang, Li[1];Cao, Xiaoming;Zhan, Wangcheng;Guo, Yanglong;Guo, Yun[1];Lu, Guanzhong

机构：[1]East China Univ Sci & Technol, Sch Chem & Mol Engn, Key Lab Adv Mat, Meilong Rd 130, Shanghai 200237, Peoples R China; East China Univ Sci & Technol, Sch Chem & Mol Engn, Res Inst Ind Catalysis, Meilong Rd 130, Shanghai 200237, Peoples R China

年份：2017

卷号：7

期号：20

起止页码：4710

外文期刊名：CATALYSIS SCIENCE & TECHNOLOGY

收录：;EI(收录号：20174304289583);WOS:【SCI-EXPANDED(收录号:WOS:000413192900015)】；

基金：This project was supported financially by the National High Technology Research and Development Program of China (2015AA034603), the National key research and development program of China (2016YFC0204300), NSFC of China (21207037, 21333003, 21571061) and the "Shu Guang" Project of the Shanghai Municipal Education Commission (12SG29).

语种：英文

外文关键词：Dust - Ionization of gases - Nitrogen oxides - Potassium - Oxygen vacancies - Sol-gel process - Sol-gels - Catalyst activity - Soot

摘要：Potassium-doped Co3O4, prepared via the sol-gel method, was pretreated by water washing and subsequently the fresh, washed catalysts were compared with pure Co3O4 in order to investigate the existing states of potassium species and their influence on the activities for NO and soot oxidation. The samples were characterized by N-2 adsorption-desorption, XRD, FT-IR, NOx-TPD, CO2-TPD, O-2-TPD and XPS. It was found that two types of K species existed in K-Co3O4, i.e., the "free" K and the "stable" K. The "free" K species, which were present as carbonates and nitrates with high mobility, could improve the contact state of catalyst-soot and thus significantly accelerate soot oxidation, but they also greatly covered the active surface of Co3O4 and were adverse for NO oxidation. The "stable" K species, which interacted strongly with Co3O4 and acted as electronic and structural modifiers, facilitated the formation of O-/O-2 -species and oxygen vacancies, exposed more surface Co3+ sites and increased the amount of the medium/strong basic sites, and as a result, they enhanced the intrinsic activities of Co3O4 for soot and NO oxidation. Both K species improved the NOx storage capacities of Co3O4, and the NOx species adsorbed on medium/strong basic sites with appropriate stability, caused by the effect of the "stable" K, were more beneficial for soot oxidation than those adsorbed on "free" K with high stability.