The Hierarchical Trimetallic FeCoNi LTH/MnMoO₄/GO Nanohybrid as an Active Catalyst with Enhanced Bifunctional Performance for Efficient Overall Water Splitting.

The development of efficient and stable bifunctional electrocatalysts based on Earth-abundant elements for sustainable hydrogen production via water splitting is of significant importance. In this study, we present the design and synthesis of a novel and highly efficient electrode based on trimetallic FeCoNi layered triple hydroxide (LTH) nanoparticles decorated over MnMoO₄ nanorods and graphene oxide (GO) electrodeposited onto fluorine-doped tin oxide (FTO) substrates. The heterostructured interface among the FeCoNi LTH nanoparticles, MnMoO₄ nanorods, and GO also offers more available catalytic sites, enhances electronic interactions, and accelerates the kinetics of water dissociation. As a result, the FeCoNi LTH/MnMoO₄/GO/FTO electrocatalyst shows improved bifunctional electrocatalytic activity toward both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), delivering a low overpotential of 238 mV for the OER and 92 mV for the HER at a current density of ±10 mA cm⁻², along with small Tafel slopes of 53 and 46 mV dec⁻¹, respectively. Furthermore, the electrocatalyst preserves outstanding stability over 31 h of continuous electrolysis with an overall water-splitting voltage of 1.57 V at 10 mA cm⁻², surpassing the performance of commercial RuO₂-based systems. This work presents a novel method for constructing high-performance and bifunctional electrocatalysts based on Earth-abundant elements for efficient water electrolysis, offering a promising pathway toward cost-effective large-scale hydrogen production.