Comprehensive design of phosphide cathodes for seawater electrolysis: from precipitation suppression, high salt resistance, to activity enhancement

Abstract

In the global shift toward low-carbon clean energy, seawater electrolysis for hydrogen production has garnered significant attention due to abundant seawater resources. Developing high-performance and stable electrocatalysts is pivotal for direct seawater hydrogen production. Transition metal phosphides (TMPs) exhibit great potential in the hydrogen evolution reaction (HER) for seawater electrolysis, thanks to their unique electronic structures, excellent electrical conductivity, and catalytic activity. This paper focuses on the design criteria of TMP-based HER electrocatalysts for seawater electrolysis, exploring reaction mechanisms and performance characterization in acidic/alkaline media. It summarizes strategies to inhibit calcium/magnesium ion precipitation and mitigate chloride ion toxicity to catalysts, analyzing their mechanisms and research advancements. Activity-enhancement strategies for TMPs – such as doping, heterojunction engineering, defect engineering, and morphology regulation – are thoroughly discussed. While TMPs offer cost advantages over traditional noble metal catalysts, practical applications face challenges. Future research should deepen HER mechanism insights, innovate characterization techniques, develop more efficient ion-precipitation inhibition strategies, and optimize TMP activity enhancement to advance seawater electrolysis technology and global sustainable energy goals.