Coral-like cobaltous sulfide/N,S-codoped carbon with hierarchical pores as highly efficient noble metal-free electrocatalyst for oxygen reduction reactions

To develop efficient nonprecious electrocatalysts for the oxygen reduction reaction (ORR) on cathode in fuel cell is urgently required. Herein, a promising coral-like N,S-codoped hierarchical porous carbon with supported cobaltous sulfide nanoparticles (CoxSy/NS-HPC) with different molar ratio of S:Co was successfully fabricated via an economic method. The role of thiourea in the preparation process was found to be triplex. It is not only as a sulfur source, but also as sulfur-nitrogen dopant, and most importantly it participates in the formation of the hierarchical porous carbon which will reduce the diffusion resistance of the reactants and expose more active sites. Benefited from the carbon support, the hybrid architecture CoS1.097/NS-HPC (S:Co = 3:1) possesses high specific surface area (549m(2)/g) and more active sites, as result it was developed as decent ORR electrocatalyst for fuel cell. Surprisingly, we found that CoS1.097/NS-HPC provides a more positive onset potential, higher cathodic current density and half-wave potential in alkaline media than CoS1.097 NPs and CoS1.097 supported on conventional mesoporous carbon (CoS1.097/MC). More importantly, compared with commercial Pt/C, CoS1.097/NS-HPC manifests higher current density, better durability, and more excellent methanol tolerance. (C) 2018 Elsevier B.V. All rights reserved.