Oxygen reduction reaction with efficient, metal-free nitrogen, fluoride-codoped carbon electrocatalysts derived from melamine hydrogen fluoride salt

In this study, we successfully demonstrate an efficient, metal-free nitrogen, fluoride-codoped carbon (NFC) oxygen reduction reaction (ORR) electrocatalyst, which is produced by directly pyrolyzing melamine hydrogen fluoride salt (using as a single N and F precursor for the first time) mixed with carbon black BP2000 in a N-2 atmosphere. The ORR electrocatalytic performances are evaluated by rotating ring disk electrode experiments in 0.1 M KOH. The NFC electrocatalyst prepared at the optimized temperature of 1000 degrees C (NFC1000) demonstrates a high ORR electrocatalytic activity with a peak potential of 0.82 V (vs. RHE), half-wave potential of 0.82 V (vs. RHE), predominant direct 4-electron reaction pathway, and good durability and methanol tolerance. Transmission electron microscopy equipped with mapping, X-ray diffraction and X-ray photoelectron spectroscopy results indicate that NFC1000 possesses an amorphous carbon structure with a homogenous codoped distribution of N and F at 2.25 at% and 1.52 at%, respectively. N-2 adsorption-desorption analysis reveals that the as-prepared NFC1000 has a high surface area of 1169 m(2) g(-1). This study provides a feasible approach to synthesize low-cost and highly efficient metal-free heteroatom-doped carbon-based electrocatalysts. (C)2018 Elsevier Inc. All rights reserved.