High-performance multimetal broccoli-like structure MnMoO4/CoWO4/NF nanocomposite as a bifunctional electrocatalyst for efficient water splitting

Abstract

Developing high-performance bifunctional water-splitting electrocatalysts is attractive for sustainable energy applications, yet significant challenges remain. Enhancing interfacial properties within heterostructured metal oxide composites offers a pathway to overcoming these limitations, such as the high cost of precious metal benchmarks and suboptimal reaction kinetics caused by intrinsic scaling relationships, by optimizing charge transport and reaction energetics. Designing advanced nanostructures with synergistic interactions between components can lower energy barriers and improve catalyst performance. In this work, a broccoli-like MnMoO₄/CoWO₄/NF nanocomposite was synthesized via a hydrothermal method. This heterostructured electrocatalyst features an engineered crystalline interface layer and leverages the synergistic effects among the multimetal oxide components. Density functional theory (DFT) calculations were employed to analyze the electronic properties, including the density of states near the Fermi level and Gibbs free energy changes (ΔGH*, ΔGO*, ΔGOH*, ΔGOOH*) for key intermediates involved in water splitting reactions. The MnMoO₄/CoWO₄/NF electrocatalyst exhibited exceptional bifunctional catalytic activity, requiring overpotentials of 258 mV for the oxygen evolution reaction (OER) and 42 mV for the hydrogen evolution reaction (HER) to reach a current density of 10 mA·cm⁻². The material demonstrated outstanding stability over 150 h of chronopotentiometry testing. The combination of experimental results and DFT analysis confirms the effectiveness of the interface engineering strategy in promoting superior catalytic performance for overall water electrolysis.