Nanocluster catalyst driving ampere-level current density in direct seawater electrolysis quantum leap towards sustainable energy

Abstract

Direct seawater electrolysis offers a promising route for sustainable hydrogen production, but challenges such as chloride corrosion, high overpotentials, and catalyst instability hinder its scalability. Here, we present a surface-engineered Cu-Ni bimetallic nanocluster catalyst anchored on Ti₃C₂Tₓ MXene via a facile polyvinylpyrrolidone (PVP)-assisted synthesis method. This pioneering design leverages the terminal functional groups (Tx = F, OH, O) of MXene to enhance metal-substrate interactions, optimize intermediate adsorption, and minimize the chloride ions adsorption, enabling efficient and durable seawater splitting. The catalyst achieves ultralow overpotentials of 29 mV (HER) and 250 mV (OER) in ultrapure water, and 49 mV (HER) and 290 mV (OER) in natural seawater at 10 mA cm⁻², closely compute with precious metal-based systems. Remarkably, it delivers a significant current density of 1.5 A cm⁻² at 2.4 V (60 °C) in an anion-exchange membrane (AEM) electrolyzer, demonstrating its potential for industrial-scale hydrogen production. The engineered surface resists chloride-induced corrosion and maintains stability for > 100 h at 100 mA cm⁻² and 70 h at 1000 mA cm⁻² in alkaline seawater. Combined experimental and density functional theory (DFT) analyses reveal the synergistic effects of Cu-Ni nanoclusters and Ti₃C₂Tₓ, elucidating the mechanisms behind enhanced reaction kinetics and durability by In-situ Raman and anticorrosion insights. The scalable, low-cost synthesis method, coupled with seamless integration into photovoltaic-electrolysis systems, achieves a remarkable rate of 1.42 mL/min of H<inf>2</inf> production. This work provides a transformative pathway for sustainable hydrogen production from seawater, addressing global energy and environmental challenges while advancing the fundamental understanding of electrocatalysis.