Redox-decoupled electrolysis for direct air capture of CO2

[Geoengineering News]

https://www.nature.com/articles/s44286-026-00391-2

Authors: Shijie Liu, Yurou Celine Xiao, Dongha Kim, Zunmin Guo, Eloi Grignon, Yuke Li, Ian Munroe, Hang Zhang, Jiexin Zhu, Zhizheng Wu, Jonathan P. Edwards, Jinqiang Zhang, Jieyuan Liu, Panagiotis Papangelakis, Yuxuan Che, Hyeon Seok Lee, Feng Li, Prasad V. Sarma, Qiyou Wang, Cai Wang, Todd Scheidt, Rui Kai Miao, Dwight Seferos, Yi Xu & David Sinton 

26 May 2026

Abstract

Electrochemical direct air capture (eDAC) leverages renewable electricity to remove atmospheric carbon dioxide (CO2), offering an alternative to carbon-intensive thermal methods. However, existing eDAC systems achieve high energy efficiency only when producing a dilute hydroxide stream (pH ≈ 13) that is incompatible with current air contactors. Attempts to generate more concentrated capture solutions encounter the fundamental limitation of proton and hydroxide recombination, lowering the current efficiency and increasing energy requirements. Here we present a decoupled strategy whereby CO2 liberation and sorbent regeneration are spatially separated, achieving high current and energy efficiency via redox-decoupled electrolysis. We tuned the redox mediator and synthesized a cation exchange membrane to ensure fast reaction kinetics, a low operating voltage and stability. The combined redox-decoupled approach achieved a capture-rate-normalized energy intensity of 0.22 GJ m2 yr t−2 (at 50 mA cm−2), a threefold improvement over previous work. Redox-decoupled eDAC provides an energy-efficient means of generating the concentrated alkaline capture solutions needed for large-scale direct air capture.

Source: Nature Chemical Engineering