Tip-Encapsulated FeNi₃ in Wood-Derived N-Doped CNTs Arrays for Efficient and Stable AEM Seawater Electrolysis.

Abstract

While anion exchange membrane seawater electrolysis (AEMSE) is a promising green hydrogen generation technology, its industrial implementation remains hindered by the lack of efficient and durable bifunctional electrocatalysts. Here, an innovative electrocatalyst featuring tip-encapsulated FeNi₃ alloy nanoparticles within N-doped carbon nanotubes arrays in situ grown on delignified wood carbon (FeNi₃-NCNTs@DWC), integrating tip effect-induced electron metal-support interactions (EMSI) with structural advantages of wood-based carbon is reported. Theoretical and experimental studies demonstrate that the strong EMSI between FeNi₃ alloys and NCNTs@DWC optimizes the interfacial electron configuration and reduces the reaction barrier, thereby enhancing activity and stability. Notably, the dual Cl^--repelling layer formed by the tip effect and Ni(Fe)OOH species inhibits Cl^-, while selectively adsorbing OH^-. Consequently, when integrated into an AEMSE cell, it delivers impressive industrial-level performance, achieving a cell voltage of 1.88 V at 2.0 A cm^- ² with over 2000 h durability (decay rate <0.0188 mV h^-1) in alkaline natural seawater. This corresponds to a 98% electrolysis efficiency, an energy consumption of 49.4 kWh kg^-1 H₂, and a record solar-to-hydrogen (STH) conversion efficiency of 19.6%. This strategy advances AEMSE toward practical implementation by coupling the tip effect with wood-derived structural engineering, thereby achieving high activity, selectivity, and long-term operational stability.