MXene-assisted CoZnCr for efficient alkaline seawater splitting and anion exchange membrane electrolyzer

Abstract

Designing efficient electrocatalysts for industrial-scale seawater splitting that can mitigate anodic corrosion while effectively driving oxygen evolution remains a significant challenge. Strategic surface engineering is crucial in developing electrocatalysts, bridging the gap between fundamental research and the practical demands of industrial water-splitting applications. In this work, we present the development of a CoZnCr@MXene heterostructure, which achieves a low cell voltage of 1.55 V at a current density of 50 mA cm⁻² and outperform RuO₂ in alkaline seawater electrolyte. The remarkable performance is attributed to synergistic enhancements arising from compositional tuning, surface engineering, and the integration of conductive supports, which collectively lead to substantial reductions in overpotentials for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The CoZnCr@MXene catalyst exhibits excellent stability and selective oxidation in alkaline seawater, with MXene incorporation effectively suppresses chloride-induced corrosion while enhancing charge transfer efficiency. Furthermore, when employed in an anion exchange membrane (AEM) electrolyzer, the CoZnCr@MXene catalyst delivers a current density of 500 mA cm⁻² at an operating voltage of 1.72 V at 60 °C, corresponding to a cell efficiency of 77.8%. The calculated hydrogen production cost is $0.86 per gallon of gasoline-equivalent (GGE), significantly below the 2026 technical target of $2.00/GGE set by the U.S. Department of Energy. This work represents a significant breakthrough in the design of long-lasting, noble-metal-free electrodes for industrial-scale alkaline seawater electrolysis.