Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea.
Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Korea.
Anal Chem. 2023 Feb 7;95(5):2901-2908. doi: 10.1021/acs.analchem.2c04461. Epub 2023 Jan 23.
The structure of an electrical double layer (EDL) at the interface of electrode/electrolyte or air/electrode/electrolyte is a fundamental aspect, however not fully understood. The potential of zero charge (PZC) is one of the clues to dictate the EDL, where the excess charge on the electrode surface is zero. Here, a nanoscale configuration of immersion method was proposed by integrating an electrochemical system into conductive atomic force spectroscopy under the amplitude modulation (AM) mode and agarose gel as the solid-liquid electrolyte. The PZC of boron-doped diamond was determined to be at 0.2 V (vs Ag/AgCl). By AM spectroscopy, the capacitive force shows remote electrification without direct electrode/electrolyte contact, which is dependent on the population of ions at the air/electrolyte interface. The surface potential by alignment of water is also evaluated. Prospectively, our study could benefit applications such as PZC measurement and non-electrode electrochemical processes at the air/electrolyte interface.
双电层（EDL）在电极/电解质或空气/电极/电解质界面的结构是一个基本方面，但尚未完全理解。零电荷电位（PZC）是决定EDL 的线索之一，在该电位下，电极表面的过剩电荷为零。在这里，通过将电化学系统集成到振幅调制（AM）模式下的导电原子力光谱中，并使用琼脂糖凝胶作为固-液电解质，提出了一种纳米级浸入方法的构型。确定掺硼金刚石的 PZC 为 0.2 V（相对于 Ag/AgCl）。通过 AM 光谱，电容力显示出无需直接电极/电解质接触的远程充电，这取决于电解质界面处的离子种群。通过水的取向评估表面电势。有前景的是，我们的研究可以有益于 PZC 测量和空气/电解质界面处的非电极电化学过程等应用。
