Co/CoO/C@B three-phase composite derived from ZIF67 modified with NaBH4 solution as the electrocatalyst for efficient oxygen evolution

Two kinds of three-phase composite materials, Co/Co(OH) 2 /C@B directly from ZIF67 modified by NaBH 4 and Co/CoO/C@B through pyrolyzation of Co/Co(OH) 2 /C@B material, are successfully synthesized and used as catalysts for the oxygen evolution reaction (OER). The structure and morphology are mainly characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS). HBZ-1 sample with the structure of Co/Co(OH) 2 /C@B has the best onset potential of 1.075 V vs. RHE at 0.1 mA cm −2 and the best catalyst stability among all of the materials researched. Especially as its pyrolyzing product, the CBZ-1 sample with the structure of Co/CoO/C@B behaves the most excellent synthetically electrocatalytic performance with low onset potential of 1.444 V vs. RHE at 0.1 mA cm −2 and a small overpotential of 390 mV at 10 mA cm −2 , which is better than that of RuO 2 . This good catalytic activity is mainly attributed to the generation of CoO phase and synergistic effect of all the phases in the composite structure. Furthermore, the CBZ-1 sample has the appropriate catalytic stability which attributed to the three-phase structure of Co/CoO/C@B composite and the existing of a little B element.