Binary metal Fe0.5Co0.5Se2 spheres supported on carbon fiber cloth for efficient oxygen evolution reaction

Abstract

Novel binary metal Fe0.5Co0.5Se2 spheres supported on carbon fiber cloth (CFC) as efficient electrocatalyst for oxygen evolution reaction (OER) have been successfully synthesized by a facile solvothermal selenization using N, N-dimethylformamide (DMF) as solvent. Firstly, Fe0.5Co0.5 nanosheets have been electrodeposited on the surface of CFC. Then, Fe0.5Co0.5/CFC as precursor has been converted to uniform Fe0.5Co0.5Se2 spheres on CFC (Fe0.5Co0.5Se2/CFC) by DMF selenization process. XRD and EDX confirm the typical crystalline structure and homogeneous elemental distribution of Fe0.5Co0.5Se2 on the surface of CFC. XPS shows the existence and valence of Fe, Co and Se. The uniform size and good dispersion of Fe0.5Co0.5Se2 spheres with the diameter of about 100 nm have been revealed by SEM and elemental mapping, which may provide more active sites for OER. The electrochemical results demonstrate that the obtained Fe0.5Co0.5Se2/CFC possesses the better OER activity with smaller overpotential, lower Tafel slope and charge transfer resistance than other samples, which may be ascribed to the uniform spherical morphology and the better intrinsic activity from binary metal Fe0.5Co0.5Se2. Moreover, the faster electron transfer rate derived from CFC support and the synergistic effect between Fe0.5Co0.5Se2 and CFC may be responsible for the enhancements of OER performances.