Facile efficient earth abundant NiO/C composite electrocatalyst for the oxygen evolution reaction

Abstract

Due to the increasing energy consumption, designing efficient electrocatalysts for electrochemical water splitting is highly demanded. In this study, we provide a facile approach for the design and fabrication of efficient and stable electrocatalysts through wet chemical methods. The carbon material, obtained by the dehydration of sucrose sugar, provides high surface area for the deposition of NiO nanostructures and the resulting NiO/C catalysts show higher activity towards the OER in alkaline media. During the OER, a composite of NiO with 200 mg C can produce current densities of 10 and 20 mA cm⁻² at a bias of 1.45 V and 1.47 V vs. RHE, respectively. Electrochemical impedance spectroscopy experiments showed the lowest charge transfer resistance and the highest double layer capacitance in the case of the NiO/C composite with 200 mg C. The presence of C for the deposition of NiO nanostructures increases the active centers and consequently a robust electrocatalytic activity is achieved. The obtained results in terms of the low overpotential and small Tafel slope of 55 mV dec⁻¹ for non-precious catalysts are clear indications for the significant advancement in the field of electrocatalyst design for water splitting. This composite material based on NiO/C is simple and scalable for widespread use in various applications, especially in supercapacitors and lithium-ion batteries.