Gerasimos S. Armatas

A new ammonium–thiourea intercalated layered metal sulfide (T-AMS-1), synthesized by the thiourea flux route, exhibits highly efficient Pb ²⁺ and Cr ⁶⁺ sorption properties and reusability under continuous flow conditions.

Ni _x P interfacial coupling reverses morphology-activity trends in MoS _x , enabling an amorphous–amorphous Ni _x P/MoS _x interface that promotes HER kinetics beyond the Volmer-limited regime.

Pore connectivity and pore entropy, that are crucial characteristics of porous solids controlling the mass transfer and diffusion of fluids through them, are linearly related.

Pore anisotropy ( B ), pore length ( L ), pore connectivity ( c ), pore entropy ( H ) and heteroscedasticity of pore size distributions are strongly related properties in oxidic materials with random porosity.

The rational design of earth‐abundant electrocatalysts is pivotal for advancing alkaline water electrolysis toward sustainable hydrogen production. Here, we report a hierarchical FeOOH@Ni ₃ N heterostructure comprising a redox‐active iron oxyhydroxide overlayer conformally coupled with a conductive trinickel nitride core directly grown on nickel foam. This hybrid catalyst drives the oxygen evolution reaction (OER) with ultralow overpotentials of 209, 245, and 284 mV at 10, 100, and 500 mA cm ⁻² , respectively, while maintaining exceptional stability under industrial‐level operations. Integrated into a two‐electrode electrolyzer, FeOOH@Ni ₃ N achieves current densities of 10, 500, and 1000 mA cm ⁻² at cell voltages of only 1.49, 1.72, and 1.78 V, outperforming noble‐metal‐based benchmarks. Operando/in‐situ spectroscopies, combined with electrokinetic and isotope‐effect analyses, reveal that enhanced intrinsic activity originates from reconstructed proton–electron transfer pathways at the Fe–Ni heterointerface. Strong interfacial coupling stabilizes high‐valent Ni ⁴⁺ = O/,Fe ⁴⁺ = O species and promotes an unconventional dual‐site hydroxyl nucleophilic attack mechanism, wherein OH ⁻ attack on Fe ⁴⁺ = O forms a bridging *OOH intermediate as the O─O bond‐forming step, synergistically assisted by adjacent Ni centers. These findings delineate a clear structure–activity–stability relationship for Fe–Ni heterostructures and showcase heterointerface engineering of conductive nitrides with oxyhydroxides as a scalable strategy for developing durable, high‐rate OER electrocatalysts.

Advancing alkaline water electrolysis for renewable energy technologies requires oxygen evolution reaction electrocatalysts that combine high activity, long‐term durability, and mechanistic clarity. Herein, we report a hierarchically engineered α‐FeOOH–FeP/Ni ₃ S ₂ electrocatalyst supported on 3D Ni foam, synthesized via a stepwise hydrothermal sulfidation, gas‐phase phosphidation, and chemical impregnation strategy. This integrated multi‐phase architecture exhibits strong interfacial coupling, enabling accelerated charge transfer and favorable oxygen evolution reaction kinetics under alkaline conditions. In situ/operando Raman, UV–vis, and electrochemical impedance spectroscopy uncover dynamic surface reconstruction under operating conditions, with reversible Fe ³⁺ /Fe ⁴⁺ redox cycling within the α‐FeOOH overlayer, pinpointing transient Fe ⁴⁺ –O species as key catalytic intermediates. The optimized catalyst attains low overpotentials of 223 and 251 mV at 10 and 100 mA cm ⁻² and sustains industrial‐level operation (>500 mA cm ⁻² ) with outstanding durability in 1.0 m KOH. When deployed in a symmetric anion exchange membrane water electrolyzer, it delivers a cell voltage of only 1.47 V at 10 mA cm ⁻² , outperforming benchmark noble‐metal‐based systems. Mechanistic studies including kinetic isotope effect and pH‐dependent analysis support a proton‐coupled electron transfer mechanism, with O–H bond cleavage as the rate‐determining step. These findings elucidate key structure–function relationships and establish a modular design strategy for advanced alkaline oxygen evolution reaction electrocatalysts.