A membrane-free electrochemical reactor for efficient oxygen removal via gravity-assisted product self-separation.

Li, Peng; Tang, Xin; Zhou, Xin; Zhao, Changming; Shen, Wanyu; Tan, Yi; Li, Deming; Jiang, Peng et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Although electrochemical technologies offer vast industrial prospects, broader adoption-particularly in consumer applications-remains constrained by high costs and limited component lifespans. Here, we present a gravity-assisted, membrane-free electrochemical oxygen (O<sub>2</sub>) removal (EOR) reactor coupling oxygen reduction (ORR) and oxygen evolution (OER) reactions. Leveraging fluid mechanics insights, buoyant O<sub>2</sub> bubbles ascend rapidly, achieving 95% product self-separation and eliminating the need for membranes or external circulation. To withstand high hydrostatic pressures and ensure a 10-year operational lifespan, we developed an integrative gas diffusion electrode (GDE) with ~85.5% conductivity and 80.2% gas permeability relative to conventional carbon paper, yet 2.2-fold higher mechanical strength and 30-fold greater stability. In a household refrigerator, our two-cell system boosts fresh-keeping capacity by 3.4-fold. Comprehensive economic analysis reveals a 22.6-fold increase in O<sub>2</sub> removal per unit cost compared with ion-exchange membrane-based reactors, underscoring this design's cost-effective, long-lived potential for diverse real-world applications.