Nonfaradaic Nanoporous Electrochemistry for Conductometry at High Electrolyte Concentration

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• 作者：Je Hyun Bae ; Chung Mu Kang ; Hyoungseon Choi ; Beom Jin Kim ; Woohyuk Jang ; Sung Yul Lim ; Hee Chan Kim ; Taek Dong Chung
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：February 17, 2015
• 年：2015
• 卷：87
• 期：4
• 页码：2443-2451
• 全文大小：483K
• ISSN：1520-6882

文摘

Nanoporous electrified surfaces create a unique nonfaradaic electrochemical behavior that is sensitively influenced by pore size, morphology, ionic strength, and electric field modulation. Here, we report the contributions of ion concentration and applied ac frequency to the electrode impedance through an electrical double layer overlap and ion transport along the nanopores. Nanoporous Pt with uniform pore size and geometry (L₂-ePt) responded more sensitively to conductivity changes in aqueous solutions than Pt black with poor uniformity despite similar real surface areas and enabled the previously difficult quantitative conductometry measurements at high electrolyte concentrations. The nanopores of L₂-ePt were more effective in reducing the electrode impedance and exhibited superior linear responses to not only flat Pt but also Pt black, leading to successful conductometric detection in ion chromatography without ion suppressors and at high ionic strengths.