▎ 摘　　要

Herein, 3D graphene is synthesized from the cation exchange resin by a cheap and efficient strategy, and then hexagonal micro-coin Co(OH)(2) particles are loaded by a simple double displacement reaction. Different analytical techniques confirm that the 3D graphene exhibit rose petal-like structure, which is decorated with Co(OH)(2) hexagonal micro coin structure. The hexagonal micro-coin Co(OH)(2) are the actual active sites for electrochemical reactions, while conductive graphene eases the transport of electrons which may further heighten their performance. The as-synthesized electrocatalysts are used to study different electrochemical measurement in an alkaline (1 M KOH) solution. The as-prepared Co(OH)(2)-3 dimensional graphene-0.5 delivered the overpotential value of -0.367 and 1.599 V (vs RHE) (10 mA cm(-2)), the calculated Tafel slope values were 96 and 110 mV dec(-1) for hydrogen and oxygen evolution reactions correspondingly. Different concentrations of Co were used to study the effect of Co on electrochemical measurements. The data shows that Co(OH)(2)-3DG-0.5 exhibited better performance than the other as-prepared Co(OH)(2) based electrocatalysts. The as-prepared electrocatalyst also shows low R-ct and reasonable stability for hydrogen and oxygen evolution reaction. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.