Optimising Electron-Rich 2D Fe,B-Ti3C2Tx/N-doped mixed metal oxide Interface for Industrial-Scale Oxygen Evolution in Seawater

Abstract

To advance seawater electrolysis technologies for green hydrogen production, it is crucial to develop efficient and durable electrocatalysts that function at high current densities during anodic reactions, preventing unwanted chlorine evolution reactions (CER). Here, we optimise an electron-rich interface between electrochemically active Fe,B-Ti3C2Tx modified MXene (FBT) and nitrogen-doped nickel molybdenum oxide (NMO) nanosheets, synthesised using an electrostatic layer-by-layer self-assembly method. Density functional theory (DFT) analysis confirms the presence of an electron-rich interface, indicated by a concentrated negative charge of -28.42e at the interface. This charge accumulation results from the high density of oxygen atoms at the interface between NMO and FBT. High electron density and robust interfacial interactions at the interface enhanced the catalyst stability, accelerated charge transfer, and improved redox kinetics. The heterostructure achieve the current density of 500 mA cm-2 at overpotentials of only 396 mV, while delivered stable current density above 1.5 A cm-2 for over 1000 h. Quantitative gas analysis confirms a Faradaic efficiency of 95.2% and an oxygen production rate of 2.96 µmol s-1 at 1.9 V vs RHE, demonstrating highly selective oxygen evolution reaction over CER. Potentiodynamic and thermodynamic analyses further demonstrate enhanced corrosion resistance via interfacial electronic stabilisation and Mo-assisted alkaline passivation. Compared with previously reported MXene- and Ni-Mo-based electrocatalysts, the engineered heterointerface exhibits improved kinetic performance and structural resilience under chloride-rich conditions. This work highlights interfacial electronic engineering as a viable strategy for enabling durable, high-current-density seawater electrolysis toward industrial hydrogen production.