Probing the electrical double layer by operando X‐ray photoelectron spectroscopy through a graphene‐carbon nanotube composite window
Probing the electrical double layer by operando X‐ray photoelectron spectroscopy through a graphene‐carbon nanotube composite window
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DOI：
10.1002/eom2.12023
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发表时间：
2020-06
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通讯作者：
Peng Wang;Yunfeng Li;Luning Wang;J. Kłos;Zhiwei Peng;N. Kim;H. Bluhm;K. Gaskell;Ping Liu;S. B. Lee;B. Eichhorn;YuHuang Wang
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作者：
Peng Wang;Yunfeng Li;Luning Wang;J. Kłos;Zhiwei Peng;N. Kim;H. Bluhm;K. Gaskell;Ping Liu;S. B. Lee;B. Eichhorn;YuHuang Wang
资助信息国家科学基金会，拨款/奖励编号：CHE1626288；科学办公室，拨款/奖励编号：DESC0001160；马里兰大学摘要众所周知，双电层自发形成在电极-电解质界面，影响许多重要的化学和物理过程以及包括电催化、电有机合成、纳米材料制备、能量储存，甚至乳液稳定在内的应用。然而，在分子水平上研究这一基本现象一直是一项具有挑战性的工作，因为电双电层被体液溶液深深地“埋藏”了。在这里，我们报道了用X射线光电子能谱从光电子透明的石墨烯-碳纳米管杂化膜电极的固体侧面定量探测离子液体的电双层。薄膜窗口超薄(1-1.5 nm)，大(~1 cm)，坚固耐用，可实现电解液的紧密密封，并利用出色的光电子信号进行定量测量。通过OPANDO监测阳离子和阴离子在外加电势作用下的布居变化，我们从实验上解析了双电层的化学结构和动力学，证实了分子动力学模拟的结果。
Funding information National Science Foundation, Grant/ Award Number: CHE1626288; Office of Science, Grant/Award Number: DESC0001160; University of Maryland Abstract The electrical double layer is known to spontaneously form at the electrodeelectrolyte interface, impacting many important chemical and physical processes as well as applications including electrocatalysis, electroorganic synthesis, nanomaterial preparation, energy storage, and even emulsion stabilization. However, it has been challenging to study this fundamental phenomenon at the molecular level because the electrical double layer is deeply “buried” by the bulk electrolyte solution. Here, we report a quantitative probing of the electrical double layer of ionic liquids from the solid side of a photoelectrontransparent graphene-carbon nanotube hybrid membrane electrode using X-ray photoelectron spectroscopy. The membrane window is ultrathin (1-1.5 nm), large (~1 cm), and robust, enabling a tight seal of the electrolyte and quantitative measurement with excellent photoelectron signals. By operando monitoring the population changes of cations and anions in response to the applied electrical potentials, we experimentally resolve the chemical structure and dynamics of the electrical double layer, which corroborate results from molecular dynamics simulations.