LAUSR

Hydrogen chloride (HCl) by-product is often produced from chlorine-consuming processes. Traditional electrochemical processes for converting HCl to chlorine (Cl2) are completed by anodic oxidation reaction coupled with cathodic reduction reactions (two major types: hydrogen evolution reaction and oxygen reduction reaction). Herein, a triiodide (I3−)/iodide (I−) redox-mediated cathode is implemented for the first time for converting HCl to Cl2. The iodide (I−) can be converted back to triiodide (I3−) by air in a reactor external to the eletrolyzer. The desirable redox potential and facile kinetics of I3−/I− offer a substantially lower operational cell voltage, reducing energy consumption by 20%–25% at a typical current density of 4 kA m−2 and improving the efficiency of Cl2 recovery. © The Author(s) 2017. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: [email protected]. [DOI: 10.1149/2.0461707jes] All rights reserved.