Study on the Catalytic Performance of Soluble Activated Carbon (AC)-ONa-Regulated CoFe2O4/Fe2O3/Co3O4-AC Composite Materials in Alkaline Hydrogen Evolution Reaction

With growing attention on renewable resources, hydrogen production as a sustainable alternative to increasingly depleted non-renewable fossil fuels has attracted significant interest. To develop economical electrocatalysts for HER that can replace platinum, this study synthesized a ternary CoFe2O4/Fe2O3/Co3O4-AC (activated carbon) nanocomposite via a urea-assisted one-step hydrothermal method, using water-soluble AC-ONa as a crystal growth regulator. The morphology and structure of the catalyst were thoroughly characterized by SEM, TEM, XRD, and XPS. Electrocatalytic water splitting performance was subsequently evaluated in 1.0 M KOH electrolyte. Results show that the catalyst requires an overpotential of 271 mV at a current density of 10 mA·cm−2, significantly outperforming single-phase Fe2O3-AC (576 mV), Co3O4-AC (511 mV), and CoFe2O4/Fe2O3/Co3O4 (291 mV). The Tafel slope is 72.2 mV·dec−1, consistent with the Volmer–Heyrovsky pathway. After a 10 h i-t stability test, the HER current remained essentially unchanged; moreover, after 1000 cyclic voltammetry cycles, the overpotential slightly decreased to 259 mV, demonstrating excellent HER stability. This work establishes a facile one-pot strategy for constructing multicomponent metal-oxide composite materials, in which soluble carbon additives play a key role in guiding interfacial growth. This method is easily scalable and avoids complicated procedures, providing a potential route for designing low-cost, highly active non-noble metal catalysts for alkaline HER.