Electrodeposited Ni–C amorphous alloys: A novel approach to enhancing catalytic activity for hydrogen evolution and urea electrooxidation

This study presents the electrodeposition of nickel–carbon (Ni–C) amorphous alloys using arginine as a carbon precursor in a modified Watts bath. Increasing carbon content leads to structural amorphization, reduced crystallite size (down to 8 nm), and enhanced electrochemically active surface area (ECSA). Electrochemical tests reveal improved catalytic performance for both hydrogen evolution (HER) and urea electrooxidation. The overpotential at −10 mA/cm² for HER is significantly reduced (−0.243 V vs. RHE), and Ni–C electrodes exhibit 10-time higher current densities for urea oxidation at +1.55 V in 1 M NaOH +0.33 M urea compared to pure nickel. The presence of carbon promotes the formation of the Ni(OH)₂/NiOOH redox couple by increasing the electrochemically active surface area and enhancing oxidation efficiency. These results highlight Ni–C alloys as promising electrode materials for energy conversion and waste valorization applications.