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121.
A variety of generator-collector systems are reviewed, from the original rotating ring-disc electrodes developed in the 1950s, to very recent developments using new geometries and microelectrodes. An overview of both theoretical and experimental aspects are given, and the power of these double electrode systems in analytical electrochemistry is illustrated with a range of applications. 相似文献
122.
Cummings CY Marken F Peter LM Tahir AA Wijayantha KG 《Chemical communications (Cambridge, England)》2012,48(14):2027-2029
Rate constants for recombination and hole transfer during oxygen evolution at illuminated α-Fe(2)O(3) electrodes were measured by intensity-modulated photocurrent spectroscopy and found to be remarkably low. Treatment of the electrode with a Co(II) solution suppressed surface recombination but did not catalyse hole transfer. Intermediates in the reaction were detected spectroscopically. 相似文献
123.
A diffusion junction between two paired gold electrodes is created in a bipotentiostatic electro-deposition process. Gold
metal is deposited simultaneously on two adjacent disc electrodes (100 μm diameter, approximately 125 μm separation) until
short-circuit conditions trigger the end point of the electro-deposition. Symmetric gold junctions with typically 5 μm average
inter-electrode gap size, 140 μm gap length, and approximately 18 μm junction depth are obtained. These paired gold electrodes
are employed in generator–collector mode to give well-defined steady-state feedback currents even for extremely low concentrations
of analyte (sub-μM) and without any contributions from capacitive charging. Four redox systems are investigated spanning a
wide range of diffusion coefficients: (1) the one-electron oxidation of iodide to iodine, (2) the two-electron oxidation of
hydroquinone to benzoquinone, (3) the two-electron reduction of alizarin red S, and (4) the one-electron oxidation of the
redox protein cytochrome c. Consistent results for these redox systems suggest that (1) the junction zone between the two electrodes is dominating the
behaviour of the electrode in particular for the slower diffusing systems and (2) the paired gold electrode junction can be
calibrated and employed for electroanalysis at very low concentrations and for a wider range of analytically relevant redox
systems.
Dedicated to Professor Keith B. Oldham, on the occasion of his 80th birthday 相似文献