Nickel oxide nanoparticles prepared by gelatin and their application toward the oxygen evolution reaction

Abstract

Green synthesis of pure nickel oxide nanoparticles (nano-NiO) in aqueous medium has been carried out using gelatin. The particles have been characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDAX). Gelatin plays an important role in the formation of the nano-NiO. TEM image shows the formation of nano-NiO with average particle size 16 nm, which agrees well with the XRD data. Moreover, efficient and stable nano-NiO-based anodes were fabricated by casting of the nano-NiO and multi-walled carbon nanotube solution (NiO-MWNT) on glassy carbon (NiO-MWNT/GC), platine (NiO-MWNT/Pt), and carbon paste (NiO-MWNT/CP) electrodes. The electrocatalysis of oxygen evolution reaction (OER) at modified electrodes has been examined using linear scanning voltammetry (LSV). The OER is significantly enhanced upon modification of the electrodes with NiO-MWNT, as demonstrated by a negative shift in the LSV curves at the NiO-MWNT-modified electrodes compared to that obtained at the unmodified ones. The maximum electrocatalytic activity toward the OER was obtained in alkaline media. The values of energy saving of oxygen gas at a current density of 5 mA cm−2 Pt, CP, and GC electrodes are 14.1, 16.0, and 21.6 kW h kg−1, respectively. The low cost as well as the marked stability of the modified electrodes makes them promising candidates in industrial water electrolysis process.