2001 Fiscal Year Final Research Report Summary
Spectroscopic Approach to Electrode Dynamics
| Project/Area Number |
12650803
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
工業物理化学
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| Research Institution | Hokkaido University |
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Principal Investigator |
OSAWA Masatoshi Hokkaido University, Catalysis Research Center, Prof., 触媒化学研究センター, 教授 (00108466)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Electrochemistry / Surface reaction / Dynamics / Electron transfer / Infrared spectroscopy / Adsorption / Fuel cells / reaction intermediate |
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| Research Abstract |
Although conventional electrochemical methods provide a myriad of kinetics and mechanistic information for heterogeneous redox processes, it is desirable to supplement this with the molecular structural information that can now be provided by in situ surface analytical techniques. Of the techniques available, infrared spectroscopy is well suited for this task since the spectral data can yield valuable information on the identity as well as reactivity of the interfacial species. In this project, surface-enhanced infrared absorption spectroscopy (SEIRAS) was used in the Kretschmann ATR configuration (a prism/thin metal film/solution geometry). The SEIRAS enables us to examine electrochemical reactions with time-resolutions down to microseconds simultaneously with electrochemical measurements. Scanning tunneling microscopy (STM) was also employed for further confirmation of the results obtained by SEIRAS. The main subjects dialed with in this project are as follows:
1. Extension of SEIRAS
… More
to Pt-group metals
The electrode materials usable for SEIRAS have long been limited only to Au, Ag, and Cu. We succeeded in preparing SEIRA-active electrodes of Pt and other Pt-group metals.
2. Electro-oxidation of C1 molecules on Pt catalysts
Using the Pt electrodes mentioned above, catalytic electro-oxidation of small organic molecules was investigated extensively with direct methanol fuel cells in mind. We found for the first time than methanol is oxidized to CO_2 via formate as a reactive intermediate.
3. Molecular adsorption at the electrochemical interface
Adsorption/desorption and reorientation of several molecules on single-crystal electrode surfaces have been investigated as a function of applied potential in conjunction with STM and electrochemical techniques.
4. Dynamics of the Dissolution of An Underpotentially Deposited Cu Layer on Au(111)
By simultaneous SEIRAS and transient current measurements, two overlapping reaction processes could be separated and analyzed kinetically.
5. Electron transfer between electrodes and adsorbed molecules
Redox behaviors of molecules immobilized at electrode surfaces were examined with time-resolved and potential-modulated SEIRAS. Very short-lived intermediates could be detected for some systems. Less
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