<p>Exploring a low-cost, stable, and high-performance catalyst to promote oxygen release and accelerate hydrogen desorption remains a significant challenge in water electrolysis technology for large-scale clean hydrogen energy production. This work reports the fabrication and electrochemical evaluation in an alkaline medium of a ternary heterostructure composite electrocatalyst, NiCoFe–LTH@NiCo₂O₄–rGO, grown in a controlled manner by direct hydrothermal deposition on nickel foam. Reduced graphene oxide (rGO) nanosheets were tightly assembled on the NiCo₂O₄ sea urchin microsphere framework and grown on the nickel porous network, which enhances the hierarchical growth of NiCoFe layered ternary hydroxide nanoflowers to improve electrochemical kinetics and promote the utilization of catalytically active sites. Electrochemical testing revealed that NiCoFe–LTH@NiCo₂O₄–rGO exhibited about 36% and 11% lower overpotentials for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared to the sample without reduced graphene oxide. Hence, only 136 mV and 324 mV were required to attain a current density of 50&#xa0;mA cm^− 2 in both HER and OER, respectively. This research presents a novel approach to the synthesis of an advanced ternary electrocatalyst that promotes catalytic reactions releasing oxygen and hydrogen.</p> Graphical abstract <p></p>