文献类型：期刊文献

英文题名：Insight into the Superior Catalytic Activity of MnO2 for Low-Content NO Oxidation at Room Temperature

作者：Yuan, Haiyang[1,2];Chen, Jianfu[1,2];Guo, Yanglong[1,2];Wang, Haifeng[1,2];Hu, P.[1,2,3]

机构：[1]East China Univ Sci & Technol, Key Lab Adv Mat, Res Inst Ind Catalysis, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Ctr Computat Chem, Sch Chem & Mol Engn, Shanghai 200237, Peoples R China;[3]Queens Univ Belfast, Sch Chem & Chem Engn, Belfast BT9 5AG, Antrim, North Ireland

年份：2018

卷号：122

期号：44

起止页码：25365

外文期刊名：JOURNAL OF PHYSICAL CHEMISTRY C

收录：;EI(收录号：20184706115678);WOS:【SCI-EXPANDED(收录号:WOS:000449888600022)】；

基金：This project was supported by the NSFC of China (21333003 and 21622305), National Ten Thousand Talent Program for Young Top-notch Talents in China, The Shanghai Shuguang scholar program (17SG30), and the Fundamental Research Funds for the Central Universities (WJ1616007).

语种：英文

外文关键词：Calculations - Room temperature - Catalysis - Catalyst activity - Manganese oxide

摘要：To achieve efficient low-content NO oxidation at room temperature is a hot but challenging topic in heterogeneous catalysis, and MnO2-based oxide catalysts have recently drawn so much attention owing to the potential activity. However, the activity origin of MnO2 and the critical rate-limiting factor are vague, impeding further catalyst optimization. Herein, by combining the first-principles calculations and microkinetic analyses, we systematically investigate the low-content NO oxidation process catalyzed by MnO2. On MnO2(110) exposed by two kinds of active sites (Mn-5c and the lattice O-bri), the favorite pathway contributing to NO oxidation is figured out by examining the complicated reaction network. This reveals that the Mars-van Krevelen mechanism with the lattice O-bri involved is preferred rather than the Langmuir-Hinshelwood one occurring at the Mn, sites alone. First, NO adsorbs at Mn-5c (as NO*) and is oxidized by the lattice O-br(i) forming NO2 # (# denotes the O-b(ri) vacancy O-v(ac)) that can desorb with an O-vac left. Second, O-2 can adsorb at O-v(ac) (O-2#) and react with NO* into an intermediate ONOO, which can break its O-O bond and release NO2. It is also found that Mn, can exclusively adsorb NO and guarantee the coverage of NO* even for the low-content NO(g) and the lattice O-b(ri) is very reactive and provides oxidative species, showing a synergetic catalytic role accounting for high activity of MnO2 for low-content NO oxidation at room temperature. Quantitatively, the adsorption energies of NO at M-n5c(E-ads (NO@Mn-5c)) and O-2 at O-vac (E-ads(O-2@O-va(c))) can serve as the important activity descriptors and increasing either of them could improve the activity of MnO2. In addition, our microkinetic results show that the NO# (NO adsorbed at the O-vac) would be a key poisoning species and deactivate MnO2 owing to its stronger adsorption in comparison with O-2, whereas the nitrate/nitrite species could not cause the blockage of active sites as expected. This work could provide a significant insight into low-content NO oxidation at room temperature catalyzed by MnO2.