文献类型：期刊文献

英文题名：Design and Preparation of Fe-N5 Catalytic Sites in Single-Atom Catalysts for Enhancing the Oxygen Reduction Reaction in Fuel Cells

作者：Zhao, Ye-Min[1];Zhang, Peng-Cheng[2];Xu, Chao[1];Zhou, Xin-You[1];Liao, Li-Mei[1];Wei, Ping-Jie[1];Liu, Ershuai[3];Chen, Hengquan[2];He, Qinggang[2];Liu, Jin-Gang[1]

机构：[1]East China Univ Sci & Technol, Key Lab Adv Mat, Sch Chem & Mol Engn, Shanghai 200237, Peoples R China;[2]Zhejiang Univ, Coll Chem & Biol Engn, Hangzhou 310027, Zhejiang, Peoples R China;[3]Northeastern Univ, Dept Chem & Chem Biol, 360 Huntington Ave, Boston, MA 02115 USA

年份：2020

卷号：12

期号：15

起止页码：17334

外文期刊名：ACS APPLIED MATERIALS & INTERFACES

收录：;EI(收录号：20202008649268);WOS:【SCI-EXPANDED(收录号:WOS:000526330900017)】；

基金：This study was financially supported by the National Nature Science Foundation of China (nos. 21571062, 21271072 to J.G.L.; nos. 21676241, 21978260 and U1732111 to Q.G.H.), the Program for Professor of Special Appointment (Eastern Scholar) at the Shanghai Institutions of Higher Learning to J.G.L. The authors acknowledge the using of the beamline 6-BM of National Synchrotron Light Source II at Brookhaven National Lab.

语种：英文

外文关键词：oxygen reduction reaction; electrocatalyst; iron porphyrin; single-atom catalyst; FeN5 active site; fuel cells

摘要：There is an urgent need for developing nonprecious metal catalysts to replace Pt-based electrocatalysts for oxygen reduction reaction (ORR) in fuel cells. Atomically dispersed M-N-x/C catalysts have shown promising ORR activity; however, enhancing their performance through modulating their active site structure is still a challenge. In this study, a simple approach was proposed for preparing atomically dispersed iron catalysts embedded in nitrogen- and fluorine-doped porous carbon materials with five-coordinated Fe-N-5 sites. The C@PVI-(DFTPP)Fe-800 catalyst, obtained through pyrolysis of a bio-inspired iron porphyrin precursor coordinated with an axial imidazole from the surface of polyvinylimidazole-grafted carbon black at 800 degrees C under an Ar atmosphere, exhibited a high electrocatalytic activity with a half-wave potential of 0.88 V versus the reversible hydrogen electrode for ORR through a four-electron reduction pathway in alkaline media. In addition, an anion-exchange membrane electrode assembly (MEA) with C@PVI-(DFTPP)Fe-800 as the cathode electrocatalyst generated a maximum power density of 0.104 W cm(-2) and a current density of 0.317 mA cm(-2). X-ray absorption spectroscopy demonstrated that a single-atom catalyst (Fe-N-x/C) with an Fe-N-5 active site can selectively be obtained; furthermore, the catalyst ORR activity can be tuned using fluorine atom doping through appropriate pre-assembling of the molecular catalyst on a carbon support followed by pyrolysis. This provides an effective strategy to prepare structure-performance-correlated electrocatalysts at the molecular level with a large number of M-N-x active sites for ORR. This method can also be utilized for designing other catalysts.