Issue 59, 2015

Novel Co–Ni–graphene composite electrodes for hydrogen production

Abstract

Active, stable and cost-effective electrocatalysts are key to water splitting for hydrogen production through electrolysis. Herein, we report the facile preparation of highly porous Co–Ni–graphene (Co–Ni–G) composite electrodes by electrodeposition for electrocatalytic applications. The incorporation of graphene into the Co–Ni matrix enhances the catalyst's activity for the hydrogen evolution reaction (HER) in an 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 the binary Co–Ni alloy indicating higher activity for hydrogen production. The addition of graphene to an electrolyte bath results in a porous encapsulated bundle of alloy nano-particles within the graphene network which effectively increases the electrochemically active surface area. As indicated by XPS analysis results, on addition of graphene the Co(0) and Ni(0) content in the deposit increases and as a result both cobalt/cobalt oxide and nickel/nickel oxide sites are evenly distributed on the Co–Ni–G electrode surface which is responsible for increased HER activity. The Tafel slope analysis showed that the HER follows a Volmer–Tafel mechanism. The structure–property relationship of the 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.

Graphical abstract: Novel Co–Ni–graphene composite electrodes for hydrogen production

Supplementary files

Article information

Article type
Paper
Submitted
27 Apr 2015
Accepted
22 May 2015
First published
22 May 2015

RSC Adv., 2015,5, 47398-47407

Author version available

Novel Co–Ni–graphene composite electrodes for hydrogen production

B. Subramanya, Y. Ullal, S. U. Shenoy, D. K. Bhat and A. C. Hegde, RSC Adv., 2015, 5, 47398 DOI: 10.1039/C5RA07627G

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