Catalytic Activity of Alkali Metal Cations for the Chemical Oxygen Reduction Reaction in a Biphasic Liquid System Probed by Scanning Electrochemical Microscopy
Catalytic Activity of Alkali Metal Cations for the Chemical Oxygen Reduction Reaction in a Biphasic Liquid System Probed by Scanning Electrochemical Microscopy
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DOI：
10.1002/chem.202001967
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发表时间：
2020-07-23
影响因子：
4.3
通讯作者：
Wittstock, Gunther
中科院分区：
文献类型：
--
作者：
Rastgar, Shokoufeh;Santos, Keyla Teixeira;Wittstock, Gunther
通过在两相液体系统中分离产物和离析物，可以增强有机溶剂中分子氧的化学还原以产生活性氧物质或伴随的有机底物的氧化。在这里，耦合的电子和离子转移过程进行了研究，以及试剂通量通过液体|用于在二氯乙烷基有机电解质中通过十甲基二茂铁（DMFc）化学还原分子氧的液体界面，其与含有碱金属离子的含水电解质形成界面。该界面稳定在移液器的孔处，通过该孔从外部施加伽伐尼电势差并进行精确调节，以强制不同的碱金属离子从水溶液转移到有机电解质。氧还原之后，通过扫描电化学显微镜（SECM）的微电极在接近界面的水相中检测H（2）O（2）。结果证明水合碱金属离子对H2O2的形成速率具有很强的催化作用，该催化作用随有机相中转移的碱金属离子的酸度而系统地变化。
Chemical reduction of dioxygen in organic solvents for the production of reactive oxygen species or the concomitant oxidation of organic substrates can be enhanced by the separation of products and educts in biphasic liquid systems. Here, the coupled electron and ion transfer processes is studied as well as reagent fluxes across the liquid|liquid interface for the chemical reduction of dioxygen by decamethylferrocene (DMFc) in a dichloroethane-based organic electrolyte forming an interface with an aqueous electrolyte containing alkali metal ions. This interface is stabilized at the orifice of a pipette, across which a Galvani potential difference is externally applied and precisely adjusted to enforce the transfer of different alkali metal ions from the aqueous to the organic electrolyte. The oxygen reduction is followed by H(2)O(2)detection in the aqueous phase close to the interface by a microelectrode of a scanning electrochemical microscope (SECM). The results prove a strong catalytic effect of hydrated alkali metal ions on the formation rate of H2O2, which varies systematically with the acidity of the transferred alkali metal ions in the organic phase.