Supersolidophobic Pt catalyst for long-term natural seawater electrolysis with hydrogen production and magnesium extraction.

Yi, Li; Chen, Chaohao; Wen, Yingjie; Zhang, Sixie; Chen, Haocheng; Zhu, Jinchao; Weng, Jiabin; Zhang, Wuyong et al. · Nat Commun · 2025

basic_science · Level V

Where this comes from

Abstract

The electrochemical synthesis of solid compounds is a critical emerging area in electrocatalysis; however, a major challenge is still remaining on severe catalysts scaling driven by strong solid-solid interactions, giving rise to rapid electrode deactivation. In this study, for the example of simultaneous synthesis of Mg(OH)<sub>2</sub> and H<sub>2</sub> from natural seawater electrolysis, we demonstrate that Pt catalyst with surface-coordinated halogens (F, Cl, Br, I) can alleviate this scaling effect (i.e., solidophobicity) by like-charge repulsion and thus regulating the local environment. Specifically, Pt-I coordination results in supersolidophobicity, achieving a successful extraction of Mg(OH)<sub>2</sub> ( > 99% purity) while stably producing H<sub>2</sub> (under 100 mA cm<sup>-2</sup> for over 5000 hours). A combination of experimental and theoretical studies reveals that, due to the like charge repulsion between I<sup>-</sup> and in situ generated OH<sup>-</sup>, the Pt-I catalyst regulates the surface pH gradient which increases the distance from the electrode surface to the Mg(OH)<sub>2</sub> nucleus (>4 μm) and facilitates homogeneous nucleation. Additionally, the scalability of the Pt-I catalyst, along with the techno-economic analysis and life cycle assessment of the natural seawater electrolysis technology are systematically demonstrated.