In situ growth of M-MO (M = Ni, Co) in 3D graphene as a competent bifunctional electrocatalyst for OER and HER

In this study, an efficient and cheap electrocatalysts are prepared by a simple synthetic method for oxygen evolution reaction (OER) hydrogen evolution reaction (HER). Nickel/nickel oxide@3dimensional hierarchical porous graphene (Ni-NiO@3DHPG) and cobalt/cobalt oxide@3dimensional hierarchical porous graphene (Co-CoO@3DHPG) electrocatalysts were obtained from cation exchange resin, nickel acetate and cobalt nitrate as a source of carbon, Ni and Co respectively. In Ni-NiO@3DHPG and CoCoO@3DHPG, metal and metal oxide nanoparticles embedded in the graphene layers, were confirmed by different techniques. The 3-D graphene in Ni-NiO@3DHPG and Co-CoO@3DHPG were thinned wall and highly porous structure and large specific surface area. The Ni-NiO@3DHPG composite displays onset potential, overpotential (10 mA cm(-2)) and Tafel value of are 1.53 V, 1.64 V and 55 mV dec(-1) for OER and -0.18 V, -0.31 V and 78 mV dec(-1) for HER respectively. Similarly, Co-CoO@3DHPG catalyst show onset potential, overpotential (10 mA cm(-2)) and Tafel are 1.59 V, 1.68 V and 65 mV dec(-1) for OER and -0.26 V, -0.40 V and 85 mV dec(-1) for HER respectively. Electrocatalysts show good stability after 4 h continuously. This simple synthetic method will open a new way for cheap and efficient electrocatalysts of other types of non-precious metals for OER and HER. (C) 2018 Published by Elsevier Ltd.