Hydrochar-Supported Nickel-Cobalt Selenide Electrocatalyst for Enhanced Oxygen Evolution Reaction Performance

Abstract This study explores the development and characterization of a nickel-cobalt selenide (Ni0.6Co0.4Se₂, 1:1, 0.01) electrocatalyst supported on hydrochar and nickel foam for the oxygen evolution reaction (OER) in alkaline water electrolysis. NiCoSe is synthesized through electrodeposition and subsequently dispersed on hydrochar. The NiCoSe/hydrochar is drop cast on a nickel foam substrate to serve as the anode. The electrocatalyst is characterized through SEM-EDS, XRD, and FTIR. The activity and stability are evaluated using CV, LSV, and EIS. XRD patterns show the formation of the mixed metal selenides, while SEM micrographs reveal the presence of microstructures that enhance the surface area of the catalyst. Elemental mapping of the NiCoSe/hydrochar shows the uniform distribution of Ni, Co, and Se. The synthesized catalyst (Ni0.6Co0.4Se₂, 1:1, 0.01) was found to deliver a current density of 10 mA-cm⁻² at an overpotential of 295.85 mV. Compared to the Ni foam alone, this composition shows a substantial improvement in the electrocatalytic activity, likely due to the reconfiguration of the electronic structure of nickel with the presence of cobalt. The presence of hydrochar contributes to a 6.55% reduction in the overpotential at 10 mA-cm⁻², highlighting its potential as a carbon support for dispersing the electrocatalyst and allowing for greater exposure of the active sites. A low Tafel slope of 72.15 mV-dec⁻¹ further indicates high electrocatalytic activity, aligning with the performance of other NixCoySez electrocatalysts. This study demonstrates that nickel-cobalt selenide can effectively lower the high overpotential of the OER, although further enhancement is needed in the conductivity of hydrochar.