Abstract

The appearance mechanism of an electrochemical oscillation (previously called oscillation B), observed for Pt electrodes in H2O2-containing acidic electrolytes in a potential region of hydrogen evolution, has been investigated. Though it is reported that electrochemical oscillations in general appear in potential regions of negative differential resistance (NDR) or hidden NDR (HNDR), impedance analyses have shown that no NDR or HNDR is present in the potential region of oscillation B. Besides, oscillation B is observed only for Pt electrodes with atomically roughened surfaces, not for electrodes with atomically flat surfaces. A possible explanation is proposed by assuming the presence of small local “active” areas in the electrode surface, in which the H2O2 reduction is not prevented by a full coverage of under-potential deposited hydrogen, contrary to the other normal “nonactive” areas occupying the major part of the electrode surface. The appearance of oscillation B is reproduced by mathematical simulation based on the model, together with the consideration of electrical coupling between the active and nonactive areas as well as solution stirring by hydrogen-gas evolution. Oscillation B can be classified into a new category of oscillators, which may be called “coupled NDR” oscillators.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.