▎ 摘　　要

In the process of developing non-metallic electro-catalyst for oxygen reduction reaction (ORR), simultaneous co-doping of N and F into Multiwalled carbon nanotubes (MWCNTs) are synthesized and their structural and electrochemical properties are investigated. Microscopic analysis confirms that N-F/MWCNTs undergo structural transformation to wrinkled graphene like structures with many open-edge active sites favorable for ORR. The enhanced catalytic activity with dominant 4 electron transfer process during ORR is evidenced for the N-F/MWCNT catalysts. N-F/MWCNT catalyst has no effect on CH3OH or CO, which makes it highly desirable as metal-free ORR catalyst for polymer electrolyte fuel cell (PEFC) applications. The developed catalyst is subjected to 10,000 repeated potential cycles in acidic media and found absolutely no degradation in their ORR activity. XPS analysis of N-F/MWCNT exhibited the presence of active graphitic-N, pyridinic-N species and active semi-ionic C-F bonds. The co-existence of all these species induces the maximum polarization of C-C bonds in the graphitic matrix and synergistically enhances the ORR. (C) 2017 The Electrochemical Society. All rights reserved.