Enhanced electrocatalytic activity towards urea oxidation on Ni nanoparticle decorated graphene oxide nanocomposite

Abstract

Hydrogen production from natural resourses and industrial waste water is of vital and duel importance to the energy and environmental issues. Urea oxidation based on cost effictive catalyst and which is substuation to the noble based electrolysers like Pt, Pd and Rh of great challange. Herein, we have fabricated effective decoration of Ni NPs on GO by chemical reduction approach and characterized by Furrier transfarm infra red (FTIR) spectroscopy, X-ray diffraction (XRD), transmissio electron microscopy (TEM), Raman spectroscopy, BET surface area measurements and X-ray photoelectron spectroscopy (XPS). In the morphological studies TEM confirms the Ni NPs (∼10 nm) on GO (∼20 nm thickness) and XRD confirms its FCC crystal structure. Further, Raman spectroscopic analysis showed the increment of ID/IG ratio more than double in GO compared to Ni@GO supports decoration of Ni NPs on GO. BET analysis also supports Ni@GO having higher surface area compared to Ni NPs and GO individuals, More significantly, binding energy of Ni is zero-valent confirmed from XPS of Ni@GO. Electrochemical activity of Ni@GO from cyclic voltammetry (CV) shows the ultrahigh current density is of 27 mA/cm2 at an ultralow onset potential of 0.30 V vs SCE having long term stability. Electrochemical impedance spectroscopy (EIS) shows the highly sensitive towards the urea oxidation reaction on Ni@GO nanocomposite. The electrocatalytic activity on Ni@GO is pH sensitive towards urea oxidation.