Microporous Film of Ternary Ni/Co/Fe Alloy for Superior Electrolytic Hydrogen Production in Alkaline Medium

This study addresses the superb electrocatalytic activity of a ternary-alloy catalyst of Ni/Co/Fe towards the hydrogen evolution reaction (HER) in alkaline medium. The dynamic hydrogen bubbling template (DHBT) method was applied to electrodeposit the catalyst layer with unique microporous foam-like morphology. The electrodeposited Ni/Co/Fe microporous film was subsequently electropassivated by cycling the potential in 1.0 M KOH. The thus-prepared catalyst supports a HER current of 10 mA cm(-2) at a significantly low overpotential of -50 mV in 1.0 M KOH (comparable to benchmarking catalysts) together with marked prolonged stability for 10 h of continuous operation at 100 mA cm(-2). Interestingly, the electropassivation process was performed with an aim to enrich the surface of the Ni/Co/Fe film with metal/oxygenated metal interfaces that facilitate the retarding water dissociation step. The obtained results, herein, indicate that the designed Ni/Co/Fe film is a promising catalyst for alkaline HER and shed some light on the impact of the electropassivation process on the electrocatalytic activity towards alkaline HER. The morphology, composition, and crystal structure of the proposed catalysts were disclosed employing SEM, EDS mapping, HRTEM, ICP-OES, XRD, and XPS surface characterization techniques.

Automated summary

This study investigates the excellent electrocatalytic activity of a Ni/Co/Fe ternary-alloy catalyst for the hydrogen evolution reaction (HER) in alkaline medium. The catalyst demonstrates high HER current and stability, achieved through electropassivation to enrich the metal/oxygenated metal interfaces. Various characterization techniques were used to analyze the morphology, composition, and crystal structure of the catalyst.