Alternating Current Measurements in Scanning Electrochemical Microscopy,Part 2: Detection of Adsorbates |
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| Authors: | Dao Trinh Dr. Michel Keddam Prof. Xosé Ramón Novoa Dr. Vincent Vivier |
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| Affiliation: | 1. LISE‐UPR 15 du CNRS, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, (France), Fax: (+33)?1 4427 4074;2. ENCOMAT group, E.T.S.E.I, Universidade de Vigo, Campus Universitario, 36310 Vigo (Spain). |
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| Abstract: | A scanning electrochemical microscope (SECM) in ac mode is used for the characterisation of the adsorption process during the hydrogen evolution reaction (HER) in sulfuric acid solution. It is shown that this technique allows quantitative analysis of the adsorption process, and measurements of the differential capacitance with the frequency as parameter are obtained. The time constant for relaxation of adsorbed hydrogen (Hads) is approximately 2 Hz, and analysis of the Nyquist plot allows direct evaluation of the charge involved. In addition, the direct comparison of the usual electrochemical impedance data and ac‐SECM results obtained simultaneously permits characterisation of processes occurring at the surface and in solution. |
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| Keywords: | adsorption electrochemistry hydrogen scanning electrochemical microscopy scanning probe microscopy |
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