Microelectrodes coated with ionically conducting polymer membranes for voltammetric detection in flowing supercritical carbon dioxide

Electrochemistry in supercritical fluids: A mini review

“…The first studies exclusively using scCO 2 as solvent were in the late 1980s by Wightman et al [7][8][9] Using water as a co-solvent and a microelectrode arrangement the group found that water aided the solvation of electrolyte [ n Hex 4 N] + [PF 6 ] − and allowed for a defined ferrocene (Fc/Fc + ) redox wave to be observed. Water was necessary to obtain an electrochemical signal with 0.64 M without electrolyte giving rise to an uncharacteristic reverse peak [7].…”

Steady-state macroscale voltammetry in a supercritical carbon dioxide medium

“…Voltammetry in scCO 2 fluids has seldom been reported, with the majority of publications utilizing ultramicroelectrodes 2,4,7 and conductive polymer coated electrodes. 3,8,9 On the macro scale the only publication known to date is that of Abbott and Harper. 5 However, the voltammetry presented was poorly defined and obtained at very slow scan rates, providing very little analytical insight.…”

Effect of supercritical deposition synthesis on dibenzothiophene hydrodesulfurization over NiMo/Al2O3 nanocatalyst

“…It is known that inorganic salts are generally not soluble in SC‐CO 2 because CO 2 is nonpolar. However, entrainers may be employed to increase solubility and conductivity in SC‐CO 2 , for example, (i) addition of small amounts of polar fluids as a cosolvent (e.g., water, methanol, ethanol, and acetone24, 25), (ii) use of a salt with a large hydrophobic cation and anion (e.g., alkylammonium + tetraphenylborate26), (iii) use of a fluorinated ion for increased solubility (e.g., tetra( p ‐fluorophenyl)borate27), or (iv) a combination of the above.…”