Nickel sulfide nanowire-filled carbon nanotubes as electrocatalysts for efficient hydrogen evolution reaction

Developing a cost-effective, efficient, and eco-friendly electrocatalyst made from non-noble materials for the hydrogen evolution reaction (HER) is challenging. This research paper presents an application of the nickel sulfide (Ni3S2) nanowires-filled multiwalled carbon nanotubes (CNTs) synthesized on carbon cloth (CC) (Ni3S2@CNTs/CC) as an efficient HER electrocatalyst. The performance of Ni3S2@CNTs/CC as a working elec-trode was examined for its hydrogen evolution ability. In a 1.0 M KOH solution, Ni3S2@CNTs/CC requires cathodic overpotentials of 381 mV and 549 mV to generate current densities of 10 mA/cm2 and 100 mA/cm2, respectively. Electrochemical impedance measurements showed a low charge transfer resistance value of 3.3 omega for Ni3S2@CNTs/CC.The evaluation of the electrochemically active surface area revealed that Ni3S2@CNTs/CC has more electro-chemical active sites and a higher roughness factor than pristine CC. Most importantly, the current density of Ni3S2@CNTs/CC did not significantly degrade after 3000 CV cycles and 12 h of constant HER. These findings suggest that Ni3S2@CNTs/CC is a cost-effective, highly functional, and stable electrode material for HER in a strongly alkaline medium.