The Electro-reduction of Carbon Dioxide in Dimethyl Sulfoxide at Gold Microdisk Electrodes:  Current | Voltage Waveshape Analysis

Abstract

The electro-reduction of carbon dioxide is studied by linear sweep and cyclic voltammetry in DMSO electrolyte solutions and at polycrystalline gold microdisk electrodes. An electrode reaction pathway is suggested. Numerical simulation of the reaction mechanism gives current | potential waveshapes in excellent agreement with those observed experimentally. Kinetic parameters for the reduction process are deduced from this waveshape approach, and the charge-transfer coefficient is found to be approximately 0.43 ( 0.05.

Voltammetric characterisation of the radical anions of 4-nitrophenol, 2-cyanophenol and 4-cyanophenol in N,N-dimethylformamide electrogenerated at gold electrodes

“…The latter was either a 3-mm diameter gold macroelectrode or a microdisk electrode either of radius 4.5 lm (Microglass Instruments, Greensborough, Australia) or 6.25 lm (manufactured in house according to a published procedure [16]). Prior to each electrochemical measurement the microdisk electrodes were polished on soft lapping pads (Kemet Ltd., UK) using alumina (Kemet Ltd., UK) of decreasing size 3-0.25 lm [17,18] before carefully drying and rinsing in the dried solvent. These electrodes were visually inspected regularly using an optical microscope, to ensure that they were not recessed from the glass surface.…”

The development of new microelectrode gas sensors: An odyssey

“…The ability to determine both respiratory gases, such as oxygen and carbon dioxide as well as inspired anaesthetic agents that include nitrous oxide, enflurane, isoflurane and sevoflurane accurately has been the focus of recent scientific interest [1][2][3][4][5][6][7][8][12][13][14][15][16][17][18][19]. Much of this work has centred on the development of an electrochemical sensor that can simultaneously measure mixtures of these gases and agents using cheaper technologies than those currently employed.…”

“…Over the last decade or so, the electrochemical measurement of oxygen, carbon dioxide and nitrous oxide has typically utilised aprotic solvents such as dimethyl sulfoxide (DMSO) [12][13][14][15][16][17][18][19] found in previous studies [12][13][14][15][16][17][18], including earlier odyssey chapters [15][16][17][18]. We do however summarize the proposed mechanisms briefly below, see Eqs.…”

“…As described previously [12][13][14][15][16]18,19], significant complications arise for the simultaneous electrochemical detection of oxygen and carbon dioxide in non-aqueous solvent since oxygen is more readily reduced than carbon dioxide. The superoxide radical anion species, generated electrochemically at lower potentials compared to carbon dioxide reduction, attacks the carbon dioxide species in a nucleophilic addition reaction leading to the formation of the peroxydicarbonate anion [9][10][11].…”

“…As a consequence, a number of methodologies have been proposed to overcome this problem and include using a metallized membrane that acts as an oxygen filter, a pulsed titration technique whereby a ''recovery titration'' step is used to determine the unreacted superoxide species [6] or with the use of microelectrodes [12][13][14][15][16][17][18][19].…”