Enhanced catalytic activity of NiSe2 by nanohybrid formation with CoO nanosheets towards overall electrocatalytic water splitting for clean energy

Abstract

Noble metal-free catalysts have recently attracted much attention towards overall electrochemical water splitting. However, poor kinetics of the reactions, involved in water splitting leads to lower hydrogen production in alkaline electrolytes. Hence, it is essential to design highly active, conductive and cost-efficient catalysts for water electrolysis. Therefore, a bifunctional electrocatalyst based on cobalt oxide (CoO) incorporated over nickel selenide (NiSe₂) supported on nickel foam (CoO/NiSe₂/NF) was synthesized via a two-step process involving hydrothermal and electrochemical deposition methods. The synthesized material was characterized thoroughly using XRD, XPS, SEM and FE-SEM. After thorough characterization, all the synthesized materials were employed as electrocatalysts towards overall water splitting. The electrochemical studies revealed that CoO/NiSe₂/NF has demonstrated excellent electrocatalytic activity towards overall electrochemical water splitting. The improved electrochemical activity of nano-hybrid could be attributed to heterogeneous structure, enhanced edge sites and the synergetic cooperation of CoO and NiSe₂. Finally, two electrode setups were prepared to perform overall water electrolysis in which CoO/NiSe₂/NF need a cell potential of 2.03 V to attain 100 mA cm⁻². The study proposes an approach for heterogeneous structure engineering to boost the catalytic performance of noble metal-free materials.