Tuning overall water dissociation performance in Fe-Ni-Co layered hydroxides via S, P, and B doping: Experimental and theoretical study

Alkaline water electrolysis (AWE) remains limited by sluggish reaction kinetics, high overpotentials, and insufficient catalyst stability. Here, we introduce an engineered hierarchical electrocatalyst in which (B, P, S)-modulated Fe-Ni-Co layered double hydroxides (LDHs) are grown on 3D-printed 316L stainless-steel microarrays with an interface of nickel nanocones (NC) to maximize active surface area and enhance mass transport. Density functional theory indicates that boron substitution at Fe sites balances oxygen-evolution reaction (OER) intermediate binding energies, creating a fully downhill free-energy profile and reducing the OER barrier. Phosphorus incorporation on Ni sites tunes the hydrogen adsorption energy toward near-thermoneutral values, optimizing hydrogen-evolution reaction (HER) kinetics. X-ray photoelectron spectroscopy confirms strong interfacial interactions, reduced oxygen vacancies, and optimized metal-anion bonding, facilitating enhanced charge transfer. The optimized asymmetric electrolyzer delivers 500 mA cm-2 at 1.93 V with Faradaic efficiencies exceeding 79 %, demonstrating a scalable route to efficient and durable AWE.