Electrosynthesis of chlorine from seawater-like solution through single-atom catalysts

Yangyang Liu, Can Li, Chunhui Tan, Zengxia Pei, Tao Yang, Shuzhen Zhang, Qianwei Huang, Yihan Wang, Zheng Zhou, Xiaozhou Liao, Juncai Dong, Hao Tan*, Wensheng Yan, Huajie Yin, Zhao-Qing Liu, Jun Huang* & Shenlong Zhao*
Nature Communications 14(1), 2475, (2023)
DOI: https://www.nature.com/articles/s41467-023-38129-w

Abstract

The chlor-alkali process plays an essential and irreplaceable role in the modern chemical industry due to the wide-ranging applications of chlorine gas. However, the large overpotential and low selectivity of current chlorine evolution reaction (CER) electrocatalysts result in significant energy consumption during chlorine production. Herein, we report a highly active oxygen-coordinated ruthenium single-atom catalyst for the electrosynthesis of chlorine in seawater-like solutions.

As a result, the as-prepared single-atom catalyst with Ru-O4 moiety (Ru-O4 SAM) exhibits an overpotential of only ~30 mV to achieve a current density of 10 mA cm−2 in an acidic medium (pH = 1) containing 1 M NaCl.

Impressively, the flow cell equipped with Ru-O4 SAM electrode displays excellent stability and Cl2 selectivity over 1000 h continuous electrocatalysis at a high current density of 1000 mA cm−2. Operando characterizations and computational analysis reveal that compared with the benchmark RuO2 electrode, chloride ions preferentially adsorb directly onto the surface of Ru atoms on Ru-O4 SAM, thereby leading to a reduction in Gibbs free-energy barrier and an improvement in Cl2 selectivity during CER.

This finding not only offers fundamental insights into the mechanisms of electrocatalysis but also provides a promising avenue for the electrochemical synthesis of chlorine from seawater electrocatalysis.