Impact of Electrolyte Temperature on Solution-Combustion Synthesized NiO/Ni Nanoparticles as Oxygen Evolution...

Oxygen evolution reaction (OER) is an important half-cell reaction in water electrolysis; however, its sluggish kinetics and high overpotential limits efficiency, require highly active and stable catalysts. This study explores the effect of electrolyte temperature on the OER activity of NiO/Ni catalyst synthesized via solution combustion synthesis. Results reveal a remarkable reduction in overpotential from 550 to 356 mV, along with a significant increase in current density, demonstrating the impact of electrolyte temperature on OER kinetics. The Tafel slope decrease progressively, reaching 75.8 mV dec^-1 at 30 °C, indicating improved reaction kinetics and charge transfer efficiency. Additionally, the increase in double-layer capacitance (C_dl) with temperature confirms greater exposure of electrochemical surface area, providing more active sites for the reaction. Stability tests over 1000 CV cycles confirmed excellent durability, making NiO/Ni a highly efficient catalyst for alkaline OER. These findings highlight the electrolyte temperature optimization as an effective approach to improving catalytic performance of NiO/Ni to act as a promising material for cost effective sustainable energy applications.