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Abstract

Hydrogen, a renewable and clean fuel, is considered as a potential energy carrier for future energy infrastructure. The electrocatalytic splitting of water by hydrogen evolution reaction (HER) is an important process with high energy conversion efficiency for hydrogen production. Active, stable and cost-effective electrocatalysts are a key to water splitting for hydrogen production through electrolysis. Herein, we report the facile preparation of highly porous Ni alloy-Graphene composite electrode by embedding graphene into the Ni alloy matrix via room temperature electrodeposition for electrocatalytic applications such as water splitting. The incorporation of graphene into Ni alloy matrix enhances the catalyst�s activity for HER in alkaline solution. The best coating exhibits a maximum current density of -850 mA cm-2 at -1.6 V, which is approximately 4 times better than that of binary Ni alloys indicating higher activity for hydrogen production. Addition of graphene to electrolyte bath results in porous encapsulated bundle of alloy nano-particles within the graphene network which effectively increases the elelctrochemically active surface area. As indicated by XPS analysis results, on addition of graphene metal content in the deposit increases and as a result both cobalt/cobalt oxide and nickel/nickel oxide sites are evenly distributed on Ni alloy- Graphene composite electrode surface which is responsible for increased HER activity. The Tafel slope analysis showed that the HER follows Volmer-Tafel mechanism. The structure-property relationship of Co-Ni-G composite coating has been discussed by interpreting field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis results.

Biography

Email: denthajekb@gmail.com