Electrocatalyst of Co Metal Atom Dispersed on N and S Co-Doped Tremelliform Carbon with Excellent Properties for Oxygen Reduction Reactions

Abstract

The introduction of sulfur is beneficial to regulate the electronic structure of M-Nx active site, thus improving oxygen reduction reactions (ORR) catalytic activity. Herein, we adopted a hydrogel method to synthesize ORR catalyst of Co metal atom dispersed on N and S co-doped tremelliform carbon (Co/NSTFC). The as-synthesized catalyst was characterized by TEM, XRD and BET, and results demonstrated that cobalt atoms are highly dispersed on porous N and S co-doped tremelliform carbon, and the specific surface area is as high as 1613 m2 g−1. And XPS analysis confirms the formation Co-Nx coordination bond, while the sulfur atom is successfully doped on the carbon support. The XPS analysis of N 1s and Co 2p prove that the introduction of sulfur atoms can improve the efficiency of electron transferring to graphite nitrogen, and to the vicinity of Co-Nx, thus increasing d-band center of Co metal atoms, consequently improving the oxygen reduction activity. The Co/NSTFC catalyst exhibits high-efficient ORR activity with half-wave potential (E1/2) of 0.882 V in 0.1 M KOH. Furthermore, the measured number of electron transfer is close to 4, and a low yield of hydrogen peroxide and superior stability were confirmed with the Co/NSTFC catalyst. This study provides new insights into the design and synthesis of high the performant ORR catalysts and promoting the development of energy conversion.