Highly dispersed active sites of Ni nanoparticles onto hierarchical reduced graphene oxide architecture towards efficient water oxidation

Herein, we reported a facile route to fabricate the Ni-NPs decorated over reduced graphene oxide (Ni/rGO) nanocomposite by an in-situ reduction method. It has been observed that the Ni/rGO drived the water oxidation at a very low overpotential of 1.42 V_RHE (ŋ = 190 mV). Furthermore, the robust catalyst presented an extraordinary porosity and imperious kinetics performance while showing a high time of flight (0.2 s⁻¹), mass activity (28 A/g) and smaller value of Tafel slope (62 mVdec⁻¹) at an applied potential of 0.35 V_RHE only. Ni/rGO also exhibited stable current density which leftovers sustained in alkaline water catalysis conducted for a prolonged time without any significant loss in catalytic efficiency. This outstanding catalytic activity of hierarchical Ni/rGO is comparable to avant-garde electrocatalytic material and even much better than the noble and transitional metal-centred eensy-weensy electrocatalytic assemblies with several drawbacks.