Surface enhanced Raman spectroscopy measurement of surface pH at the electrode during Ni electrodeposition reaction

Takayuki Homma, Masahiro Kunimoto, Moe Sasaki, Tomoya Hanai, Masahiro Yanagisawa

    Research output: Contribution to journalArticlepeer-review

    4 Citations (Scopus)

    Abstract

    Abstract: In this work, we developed a precise approach to analyze local proton concentration at the solid/liquid interface of electrodes, i.e. “surface pH”, during electrochemical reactions. For this, surface enhanced Raman spectroscopy (SERS) was applied to analyze pH-dependent structural changes of the –COOH group of p-mercaptobenzoic acid (p-MBA) modified onto Au nanoparticles (NPs) on the substrate close to a working electrode. Measurements using this system identified deprotonation of –COOH of p-MBA. Since preliminary experiments and density functional theory calculations suggest that the pKa of p-MBA attached to Au NPs is close to that in bulk solution, the SERS results indicate pH increase due to proton consumption by the cathodic overpotential of the working electrode. As an example, we applied this system to surface pH monitoring in electrodeposition process of Ni in an acidic bath, which indicated the validity of our method for precise detection of pH changes at electrode interfaces in situ. Graphical Abstract: [Figure not available: see fulltext.]

    Original languageEnglish
    Pages (from-to)1-7
    Number of pages7
    JournalJournal of Applied Electrochemistry
    DOIs
    Publication statusAccepted/In press - 2017 Dec 14

    Keywords

    • Au nano particles
    • Electrodeposition
    • Surface enhanced Raman spectroscopy
    • Surface pH

    ASJC Scopus subject areas

    • Chemical Engineering(all)
    • Electrochemistry
    • Materials Chemistry

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