Electron-Transfer Rate in Potential-Modulated Redox Reactions with Electro-Active Optical Waveguides

Area of Science:

• Electrochemistry
• Spectroelectrochemistry
• Surface Science

Background:

• Electron-transfer rate is crucial for understanding redox reactions.
• Existing methods for measuring electron-transfer rates can be limited in sensitivity or scope.
• Spectroelectrochemical techniques offer a powerful approach to probe interfacial processes.

Purpose of the Study:

• To develop and validate a novel methodology for determining electron-transfer rates in electrically driven redox reactions.
• To apply this methodology to investigate the electron-transfer kinetics of cytochrome c adsorbates.
• To explore the influence of surface density and ionic strength on electron-transfer processes.

Main Methods:

• Development of a novel methodology combining optical and electrical impedance data from simultaneous spectroelectrochemical measurements.
• Utilizing a highly sensitive, single-mode, electro-active, integrated optical waveguide platform.
• Experimental validation of the methodology using cytochrome c adsorbates on an indium tin oxide electrode.

Main Results:

• The developed methodology was experimentally corroborated for accuracy.
• Electron-transfer rates of cytochrome c adsorbates were successfully investigated at low concentrations.
• Higher surface densities of cytochrome c and higher ionic strengths in the electrolyte solution were observed to decrease the electron-transfer rate.

Conclusions:

• The novel spectroelectrochemical methodology provides a reliable means to determine electron-transfer rates.
• Surface density and ionic strength are significant factors influencing electron-transfer kinetics at electrode interfaces.
• This approach offers new possibilities for studying interfacial electron transfer in various redox systems.