Synthesis and characterization of (Co, Fe, Ni)9 S8 nanocomposite supported on reduced graphene oxide as an efficient and stable electrocatalyst for methanol electrooxidation toward DMFC

Abstract

In this study, Co4S3, Fe3S4, and NiS nanoparticles as a nanocomposite in the form of a new composite called (CoFeNi)9 S8 (CFNS) were synthesized by a facile hydrothermal method. Then, graphene oxide supported (CoFeNi)9 S8 nanoparticles (CFNS/rGO) were prepared and methanol oxidation reaction evaluated on CFNS/rGO electrocatalyst. X-ray diffraction and energy dispersive X-ray spectroscopy analysis were used to investigate the structure and phase identification of electrocatalyst. Homogenous dispersion of CFNS nanoparticles on rGO was confirmed by FESEM and HRTEM images. The electrocatalytic activity of CFNS/rGO hybrid was assessed by cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectroscopy techniques. The CFNS/rGO exhibited high electrocatalytic activity for methanol electrooxidation in alkaline media. The significant activity of CFNS/rGO assigned to synergistic effects between Co, Fe, and Ni, suitable dispersion of CFNS nanoparticles on rGO, high surface area, and porous structure of rGO that comforts the diffusion of methanol. Therefore, the CFNS/rGO catalyst has enough potential for application in the direct methanol fuel cell.