A clean and membrane-free chlor-alkali process with decoupled Cl2 and H2/NaOH production

Mengyan Hou; Long Chen; Zhaowei Guo; Xiaoli Dong; Yonggang Wang; Yongyao Xia

doi:10.1038/s41467-018-02877-x

A clean and membrane-free chlor-alkali process with decoupled Cl₂ and H₂/NaOH production

Nat Commun. 2018 Jan 30;9(1):438. doi: 10.1038/s41467-018-02877-x.

Authors

Mengyan Hou¹, Long Chen¹, Zhaowei Guo¹, Xiaoli Dong¹, Yonggang Wang², Yongyao Xia³

Affiliations

¹ Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, 200433, Shanghai, China.
² Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, 200433, Shanghai, China. ygwang@fudan.edu.cn.
³ Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, 200433, Shanghai, China. yyxia@fudan.edu.cn.

Abstract

Existing chlor-alkali processes generally use asbestos, mercury or fluorine-containing ion-exchange membranes to separate the simultaneous chlorine production on the anode and hydrogen production on the cathode, and form sodium hydroxide in the electrolyte. Here, using the Na⁺ de-intercalation/intercalation of a Na_0.44MnO₂ electrode as a redox mediator, we decouple the chlor-alkali process into two independent steps: a H₂ production step with the NaOH formation in the electrolyte and a Cl₂ production step. The first step involves a cathodic H₂ evolution reaction (H₂O → H₂) and an anodic Na⁺ de-intercalation reaction (Na_0.44MnO₂ → Na_0.44-xMnO₂), during which NaOH is produced in the electrolyte solution. The second step depends on a cathodic Na⁺ intercalation reaction (Na_0.44-xMnO₂ → Na_0.44MnO₂) and an anodic Cl₂ production (Cl → Cl₂). The cycle of the two steps provides a membrane-free process, which is potentially a promising direction for developing clean chlor-alkali technology.

Publication types

Research Support, Non-U.S. Gov't