Abstract:
Electrochemical water electrolysis has emerged as a pivotal technology for sustainable energy conversion and the realization of carbon neutrality, owing to its independence from fossil fuels, production of high-purity hydrogen, and inherently clean and efficient process. Nevertheless, the widespread adoption of this technology remains limited by the reliance on Pt-based noble metal catalysts, which, despite their exceptional catalytic activity for the hydrogen evolution reaction (HER), suffer from high cost and scarcity, thereby impeding their large-scale implementation. Consequently, the development of cost-effective, efficient, and durable non-precious metal HER catalysts has garnered considerable research attention. In this study, an Fe-doped nickel hypophosphite (Fe-Ni(H
2PO
2)
2) catalyst was successfully synthesized on a nickel foam (NF) substrate via a facile one-step electrochemical deposition method. Comprehensive structural and morphological analyses revealed that the catalyst exhibits a uniform microspherical morphology with an amorphous structure, which significantly increases the exposure of electrochemically active sites and enhances catalytic efficiency. Furthermore, the incorporation of Fe was found to modulate the electronic environment of Ni active sites through a synergistic electronic interaction, thereby facilitating charge transfer across the electrode–electrolyte interface and improving the intrinsic HER activity. Electrochemical evaluations demonstrated that the optimized catalyst, obtained under a deposition current of 500 mA with an Fe atomic doping ratio of 30%, exhibited superior HER performance, requiring an overpotential of only 72 mV to achieve a current density of 10 mA/cm
2 and featuring a Tafel slope of 65 mV/dec, indicative of favorable reaction kinetics. The catalyst also displayed a large electrochemically active surface area and excellent charge transfer properties, contributing to the high density of active sites and enhanced HER kinetics. Notably, the Fe-Ni(H
2PO
2)
2 catalyst maintained stable performance over 20 h of continuous operation with negligible degradation, underscoring its outstanding electrochemical durability. The Fe-Ni(H
2PO
2)
2 catalyst demonstrates significant promise for practical application in green, efficient, and economically viable hydrogen production via water electrolysis.