Scanning electrochemical microscopy (SECM): Study of the adsorption and desorption of hydrogen on platinum electrodes in Na2SO4 solution (pH=7)
Scanning electrochemical microscopy (SECM): Study of the adsorption and desorption of hydrogen on platinum electrodes in Na2SO4 solution (pH=7)
Hydrogen adsorption and desorption at polycrystalline platinum electrodes in a neutral Na2SO4 solution were studied with a scanning electrochemical microscope. Experiments were carried out with the tip-substrate voltammetry mode, where the faradaic current flowing to the tip is recorded while cycling the potential of the substrate, and with the tip-substrate chronoamperometry mode, where the tip faradaic current is recorded as a function of time following the application of a potential step to the substrate. The tip current was made pH sensitive by holding the tip potential in a region where a pH- dependent reaction occurs. Proton reduction was used to monitor pH decrease, whereas platinum oxide formation was selected to detect pH increase. The results showed that a transient pH decrease as high as 2.3 pH units exists during hydrogen desorption and that a great pH increase occurs during hydrogen adsorption. The mechanisms of hydrogen adsorption and desorption were analysed by comparing tip current vs. substrate potential curves, which reflect the exchange of H+ between the adsorbed layer and the solution, with substrate current vs. substrate potential curves, which reflect the exchange of electrons between the adsorbed layer and the electrode. New conclusions have been drawn.
secm, scanning electrochemical microscope, hydrogen adsorption-desorption, platinum electrode
single-crystal electrodes, acidic aqueous-media, polycrystalline platinum, stepped surfaces, mechanism, pt(100), behavior, polyaniline, absorption, evolution
99-107
Yang, Yi-Fu
d666aad3-e154-4859-be89-86c4a0dacc58
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e
21 November 1996
Yang, Yi-Fu
d666aad3-e154-4859-be89-86c4a0dacc58
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e
Yang, Yi-Fu and Denuault, Guy
(1996)
Scanning electrochemical microscopy (SECM): Study of the adsorption and desorption of hydrogen on platinum electrodes in Na2SO4 solution (pH=7).
Journal of Electroanalytical Chemistry, 418 (1-2), .
Abstract
Hydrogen adsorption and desorption at polycrystalline platinum electrodes in a neutral Na2SO4 solution were studied with a scanning electrochemical microscope. Experiments were carried out with the tip-substrate voltammetry mode, where the faradaic current flowing to the tip is recorded while cycling the potential of the substrate, and with the tip-substrate chronoamperometry mode, where the tip faradaic current is recorded as a function of time following the application of a potential step to the substrate. The tip current was made pH sensitive by holding the tip potential in a region where a pH- dependent reaction occurs. Proton reduction was used to monitor pH decrease, whereas platinum oxide formation was selected to detect pH increase. The results showed that a transient pH decrease as high as 2.3 pH units exists during hydrogen desorption and that a great pH increase occurs during hydrogen adsorption. The mechanisms of hydrogen adsorption and desorption were analysed by comparing tip current vs. substrate potential curves, which reflect the exchange of H+ between the adsorbed layer and the solution, with substrate current vs. substrate potential curves, which reflect the exchange of electrons between the adsorbed layer and the electrode. New conclusions have been drawn.
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Published date: 21 November 1996
Additional Information:
WA976
Keywords:
secm, scanning electrochemical microscope, hydrogen adsorption-desorption, platinum electrode
single-crystal electrodes, acidic aqueous-media, polycrystalline platinum, stepped surfaces, mechanism, pt(100), behavior, polyaniline, absorption, evolution
Identifiers
Local EPrints ID: 179261
URI: http://eprints.soton.ac.uk/id/eprint/179261
ISSN: 1572-6657
PURE UUID: 4e798db6-e75f-42f2-8632-0ad5fa96adb7
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Date deposited: 01 Apr 2011 09:27
Last modified: 09 Jan 2022 02:43
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Author:
Yi-Fu Yang
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