Xiao Mengjun, Wu Qianbao, Ku Ruiqi, Zhou Liujiang, Long Chang, Liang Junwu, Mavrič Andraž, Li Lei, Zhu Jing, Valant Matjaz, Li Jiong, Zeng Zhenhua, Cui Chunhua
Molecular Electrochemistry Laboratory, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, China.
School of Physics, Harbin Institute of Technology, Harbin, 150001, China.
Nat Commun. 2023 Sep 2;14(1):5356. doi: 10.1038/s41467-023-41070-7.
Electrochemical chlorine evolution reaction is of central importance in the chlor-alkali industry, but the chlorine evolution anode is largely limited by water oxidation side reaction and corrosion-induced performance decay in strong acids. Here we present an amorphous CoOCl catalyst that has been deposited in situ in an acidic saline electrolyte containing Co and Cl ions to adapt to the given electrochemical condition and exhibits ~100% chlorine evolution selectivity with an overpotential of ~0.1 V at 10 mA cm and high stability over 500 h. In situ spectroscopic studies and theoretical calculations reveal that the electrochemical introduction of Cl prevents the Co sites from charging to a higher oxidation state thus suppressing the O-O bond formation for oxygen evolution. Consequently, the chlorine evolution selectivity has been enhanced on the Cl-constrained Co-O sites via the Volmer-Heyrovsky pathway. This study provides fundamental insights into how the reactant Cl itself can work as a promoter toward enhancing chlorine evolution in acidic brine.
电化学析氯反应在氯碱工业中至关重要，但析氯阳极在很大程度上受到水氧化副反应以及在强酸中由腐蚀引起的性能衰减的限制。在此，我们展示了一种非晶态CoOCl催化剂，该催化剂已原位沉积在含有Co和Cl离子的酸性盐电解质中，以适应特定的电化学条件，并在10 mA cm时表现出约100%的析氯选择性，过电位约为0.1 V，且在500 h以上具有高稳定性。原位光谱研究和理论计算表明，Cl的电化学引入可防止Co位点充电至更高氧化态，从而抑制析氧的O-O键形成。因此，通过Volmer-Heyrovsky途径，在Cl受限的Co-O位点上析氯选择性得到了增强。这项研究为反应物Cl本身如何作为促进剂增强酸性盐水中的析氯反应提供了基本见解。
