Synergistically enhanced electrocatalytic performance of NiO infused crystalline graphitic carbon towards overall water splitting

Developing high-performance electrocatalysts to achieve catalytically active and kinetically feasible reaction sites with structural strength is challenging. Herein, a facile hydrothermal method is reported for compositing the NiO nanoparticles with high crystalline graphitic carbon (GC). With superior electronic conductivity, GC is functionalized with active NiO (NiO/GC) to improve electrocatalytic activity both intrinsically and extrinsically. The NiO/GC electrocatalyst exhibits a minimal overpotential of 260 mV and 177 mV at 10 mA cm−2 with a Tafel slope value of 63 mV dec−1 and 119 mV dec−1 during the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The alkaline water electrolysis system designed with NiO/GC as a bifunctional electrocatalyst performs overall water splitting at a low cell voltage of 1.7 V to deliver 10 mA cm−2.