Tang Daojian, Wu Lei, Li Liubo, Fu Niankai, Chen Chuncheng, Zhang Yuchao, Zhao Jincai
Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190 P. R. China
University of Chinese Academy of Sciences Beijing 100049 P. R. China.
Chem Sci. 2024 Jan 16;15(8):3018-3027. doi: 10.1039/d3sc06337b. eCollection 2024 Feb 22.
Photo(electro)catalytic chlorine oxidation has emerged as a useful method for chemical transformation and environmental remediation. However, the reaction selectivity usually remains low due to the high activity and non-selectivity characteristics of free chlorine radicals. In this study, we report a photoelectrochemical (PEC) strategy for achieving controlled non-radical chlorine activation on hematite (α-FeO) photoanodes. High selectivity (up to 99%) and faradaic efficiency (up to 90%) are achieved for the chlorination of a wide range of aromatic compounds and alkenes by using NaCl as the chlorine source, which is distinct from conventional TiO photoanodes. A comprehensive PEC study verifies a non-radical "Cl" formation pathway, which is facilitated by the accumulation of surface-trapped holes on α-FeO surfaces. The new understanding of the non-radical Cl activation by semiconductor photoelectrochemistry is expected to provide guidance for conducting selective chlorine atom transfer reactions.
光（电）催化氯氧化已成为一种用于化学转化和环境修复的有用方法。然而，由于游离氯自由基的高活性和非选择性特性，反应选择性通常仍然较低。在本研究中，我们报道了一种光电化学（PEC）策略，用于在赤铁矿（α-Fe₂O₃）光阳极上实现可控的非自由基氯活化。通过使用NaCl作为氯源，对多种芳香族化合物和烯烃进行氯化反应，实现了高选择性（高达99%）和法拉第效率（高达90%），这与传统的TiO₂光阳极不同。一项全面的PEC研究验证了一种非自由基“Cl⁺”形成途径，该途径由α-Fe₂O₃表面捕获的空穴积累所促进。半导体光电化学对非自由基Cl活化的新认识有望为进行选择性氯原子转移反应提供指导。
