Nitrogen, Sulfur and Fluorine Tri-Doped Carbon Supporting Cobalt Nanoparticles for Oxygen Reduction Catalysis

Abstract

Non-precious metal catalysts for oxygen reduction reaction (ORR) are urgently needed in clean energy conversion systems, such as fuel cells and metal-air batteries. Cobalt nanoparticles supported on nitrogen, sulfur and fluorine tri-doped carbon (Co/NSF-C) is a new class of non-precious metal materials, which exhibit ORR catalysis in alkaline media. These catalysts are prepared by pyrolyzing cobalt chloride and melamine sulfuric acid hydrogen fluoride with carbon black in a nitrogen atmosphere at temperatures from 600 °C to 900 °C with Co content from 0 to15wt%. The electrochemical performance of the catalysts shows hat the best temperatures and the best cobalt contents in descending order are 700 °C > 600 °C > 800 °C > 900 °C and 10 wt% ≈ 5 wt% > 15 wt% > 0 wt%, respectively. The catalyst with cobalt content of 10 wt% and prepared at 700 °C (Co/NSF-C700) has a mesopore surface with high heteroatom defect density and a specific surface area of 875 m2 g−1. Co/NSF-C700 exhibits the best ORR catalytic performance with a mainly 4-electron reaction pathway, an ORR peak potential of 0.856 V and the half-wave potential of 0.855 V, as well as a good stability in 0.1 M KOH.