Facile synthesis of Co(OH)2 magnetic nanoflake deposited on reduced graphene oxide nanoflake as an efficient bi-functional electrocatalyst for oxygen evolution/reduction reactions in alkaline media

Here, a new hybrid material consisting Co(OH)2 magnetic nanoflake (MNF-Co(OH)2) grown on reduced graphene oxide nanoflake (MNF-Co(OH)2@RGONF) was synthesized as an excellent bi-functional electrocatalyst for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in alkaline media, by a facile and inexpensive technique. The onset potential, current density at 2.025 V (vs. RHE), and Tafel slope of OER in 1.0 mol L− 1 KOH for MNF-Co(OH)2@RGONF modified glassy carbon electrode (MNF-Co(OH)2@RGONF/GCE) were about 1.505 mV (vs. RHE), 227 mA cm− 2 and 63 mV dec− 1, respectively. So that the current density and Tafel slope of this electrocatalyst are better than commercial IrO2. Furthermore, it was concluded that MNF-Co(OH)2@RGONF/GCE due to four-electron transfer mechanism, an overvoltage about 775 mV (vs. RHE), better durability and stronger resistance rather than Pt/C (20%) at 0.436 V in KOH 0.10 mol L− 1 (with the addition of methanol to electrochemical cell), has a high catalytic activity for ORR.