A metal–organic-framework/carbon composite with enhanced bifunctional electrocatalytic activities towards oxygen reduction/evolution reactions

A Co-OBA/C (OBA = 4,4′-Oxybis (benzoic acid)) composite catalyst was synthesized by integrating MOF (Co-OBA) with black carbon through a hydrothermal process. The catalyst was characterized using X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The catalytic activities toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) were evaluated by linear-sweep voltammetry (LSV) in an alkaline electrolyte . The ligand mode of the carboxylate binding is chelating coordination and the ligand mode of imidazole is monodentate ligand in the Co-OBA/C catalyst. The Co-OBA/C catalyst shows much better ORR, OER and bifunctional activities than the Co-OBA + C catalyst due to the synergistic effect between Co-OBA and carbon black in the Co-OBA/C catalyst.