Membrane‐Free Direct Seawater Electrolysis via Redox Mediator for H <sub>2</sub> Production

A AJing Song (State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering Donghua University Shanghai 201620 China) S Siyuan Mei (State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering Donghua University Shanghai 201620 China) X Xin Jin Y Yuanyuan Ma (Nurturing Center of Jiangsu Province for State Laboratory of AI Imaging & Interventional Radiology, Department of Radiology, Zhongda Hospital, School of Medicine) J JianPing Yang

Abstract

Abstract Acidic seawater electrolysis offers a promising strategy for sustainable hydrogen production. However, its practical application still faces critical challenges including membrane dependency, complex seawater pretreatment, and limited compatibility with intermittent renewable energy. Herein, we construct a decoupled seawater direct electrolysis (DSDE) system employing TQBQ‐COF (Covalent Organic Framework) as a solid‐state redox mediator, enabling membrane‐ and desalination‐free operation. TQBQ‐COF exhibits excellent electrochemical performances in both acidic deionized water and acidic seawater, demonstrating that common seawater ions do not interfere with its redox activity. When coupled with a Ru‐modified TQBQ‐COF catalyst (COF‐Ru), the DSDE system decouples anode and cathode reactions, allowing flexible integration with intermittent renewable energy for high‐purity H 2 and Cl 2 production. This system achieves a hydrogen production cost of US$2.5 per kg H 2 , offering a simplified, robust, and scalable solution for practical seawater electrolysis.

Article Details

Volume / Issue Vol. 64, Issue 52
Published December 22, 2025
ISSN 1433-7851
Publisher Wiley

Journal Info

Angewandte Chemie International Edition

Wiley

ISSN: 1433-7851 Physical Sciences

Authors (5)

A

AJing Song

State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering Donghua University Shanghai 201620 China

S

Siyuan Mei

State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering Donghua University Shanghai 201620 China

X

Xin Jin

Y

Yuanyuan Ma

Nurturing Center of Jiangsu Province for State Laboratory of AI Imaging & Interventional Radiology, Department of Radiology, Zhongda Hospital, School of Medicine

J

JianPing Yang