Enhancing the performance of nickel-cobalt selenide electrocatalyst on hydrochar support for oxygen evolution reaction

This study explores the development and characterization of a nickel-cobalt selenide (Ni 0.6 Co 0.4 Se 2 , 1:1, 0.01) electrocatalyst supported on hydrochar and nickel foam for the oxygen evolution reaction (OER) in alkaline water electrolysis. NiCoSe was synthesized via electrodeposition, dispersed on hydrochar, and drop cast on a nickel foam substrate to form the anode. The electrocatalyst is characterized through SEM-EDS, XRD, and FTIR. The activity and stability are evaluated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). XRD analysis confirmed the formation of the mixed nickel-cobalt selenide phases, while SEM revealed the presence of porous and rough microstructures that enhance the surface area of the electrocatalyst. Elemental mapping of the NiCoSe/hydrochar shows the uniform distribution of Ni, Co, and Se. The synthesized electrocatalyst (Ni 0.6 Co 0.4 Se 2 , 1:1 loading ratio, 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, the electrocatalyst shows a substantial improvement in the electrocatalytic activity through overpotential reduction, 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 which highlights 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 nickel-cobalt selenide electrocatalysts. These findings demonstrate the potential of hydrochar-supported nickel-cobalt selenide as an effective electrocatalyst for OER, although further enhancement is needed in the conductivity of hydrochar.