TY - JOUR
T1 - Methylene Green Voltammetry in Aqueous Solution
T2 - Studies Using Thermal, Microwave, Laser, or Ultrasonic Activation at Platinum Electrodes
AU - Akkermans, Richard P.
AU - Roberts, Sarah L.
AU - Marken, Frank
AU - Coles, Barry A.
AU - Wilkins, Shelley J.
AU - Cooper, Jonathan A.
AU - Woodhouse, Katy E.
AU - Compton, Richard G.
PY - 1999/11/1
Y1 - 1999/11/1
N2 - The voltammetry of the aqueous two-electron reduction of the phenothiazine dye methylene green, known to be passivating at platinum electrodes, is reported under simultaneous activation with each of the following techniques: thermal activation in the temperature range 15-80°C, pulsed microwave activation with a modified 800 W, 2.45 GHz domestic microwave oven, 10 Hz pulsed laser activation with a Nd:YAG laser at 532 nm, sonication, or ultrasonic activation where a 20 kHz ultrasonic horn probe is employed to generate an aqueous/ organic solvent emulsion. The relative merits of the five methodologies are compared and discussed in terms of surface activation and cleaning, mass-transport enhancement, and reduction mechanism elucidation. Comparisons are also drawn with the voltammetry of methylene blue, a dye of the same family. This is the first full report of both the effects of microwave heating on surface redox electrochemistry and of the sonoemulsion technique.
AB - The voltammetry of the aqueous two-electron reduction of the phenothiazine dye methylene green, known to be passivating at platinum electrodes, is reported under simultaneous activation with each of the following techniques: thermal activation in the temperature range 15-80°C, pulsed microwave activation with a modified 800 W, 2.45 GHz domestic microwave oven, 10 Hz pulsed laser activation with a Nd:YAG laser at 532 nm, sonication, or ultrasonic activation where a 20 kHz ultrasonic horn probe is employed to generate an aqueous/ organic solvent emulsion. The relative merits of the five methodologies are compared and discussed in terms of surface activation and cleaning, mass-transport enhancement, and reduction mechanism elucidation. Comparisons are also drawn with the voltammetry of methylene blue, a dye of the same family. This is the first full report of both the effects of microwave heating on surface redox electrochemistry and of the sonoemulsion technique.
UR - http://www.scopus.com/inward/record.url?scp=0000880080&partnerID=8YFLogxK
U2 - 10.1021/jp992164b
DO - 10.1021/jp992164b
M3 - Article
AN - SCOPUS:0000880080
SN - 1520-6106
VL - 103
SP - 9987
EP - 9995
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 45
ER -