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Low‐Voltage Gaseous HCl Electrolysis with an Iron Redox‐Mediated Cathode for Chlorine Regeneration
Author(s) -
Zhao Yun,
Gu Shuang,
Gong Ke,
Zheng Jie,
Wang Junhua,
Yan Yushan
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201704749
Subject(s) - electrolysis , anode , cathode , chemistry , redox , faraday efficiency , chlorine , inorganic chemistry , chemical engineering , electrode , organic chemistry , electrolyte , engineering
Gaseous HCl as a by‐product is often produced from chlorination processes using Cl 2 gas. Onsite Cl 2 regeneration from HCl is highly desirable as it eliminates the need to buy new Cl 2 and dispose HCl waste. A gaseous HCl electrolysis with Fe 3+ /Fe 2+ redox‐mediated cathode is demonstrated for Cl 2 regeneration. HCl is oxidized to generate Cl 2 and protons in the anode while Fe 3+ is reduced to Fe 2+ in the cathode. Simultaneously Fe 3+ is regenerated by chemical oxidation of Fe 2+ by oxygen (air) that also produces water. A low operational voltage and high coulombic efficiency are achieved by using a novel composite porous membrane and hydrophobic anode. Specifically, a cell voltage of only 0.64 V is needed at the typical current density of 4 kA m −2 , leading to a low energy consumption of 483 kWh per ton of Cl 2 (124 kJ molCl2−1 ) which is about 50–55 % of state‐of‐the‐art HCl electrolysis processes.