Electrochemistry behaviours of C₆₀ attached with physical method: solvent casting
and mechanically attachment, to various solid-state electrode surfaces (gold, glassy
carbon and platinum) were studied in aqueous and non-aqueous solution
containing a variety of doping cations such as Group I alkali-metal cations and
quatemaI)'-ammonium R4N+. Electroreduction and reoxidation of microcrystalline
C₆₀ in 0.1 M TBAPF₆/ACN showed one to four pairs, characteristic solid state
current-potential curve, with only first and second pairs appeared to be stable and
reversible.
In contact with 0.1 M TBAPF₆/ACN, the large peak separation and small
maximum at reverse scan observed with cyclic voltammetric experiments, as well
as the current-time transients obtained in chronoamperometric experiments
produce evidence of nucleation and growth (N&G) processes at the electrolytesolid-
electrode interface. C60 cast onto glassy carbon or gold electrodes showed very different results of
cyclic voltammetry (CV), chronocoulometry (CC), and chronoamperometry (CA)
in aqueous and non-aqueous solutions. With the presence of alkali-metal cations in aqueous electroyte, MnC₆₀ (M = LI⁺, Na⁺, K⁺, R⁺, Cs⁺, n = 1 to 6) was formed at
the end of potential scan, and the loss of faradaic activity when oxidizing MnC60 at
reverse of potential scan indicated the formation of non-electroactive and
irreversible species. In aqueous solution, CV results showed a parallel shift in
reduction peak position as the sizes of cation increased.
A glassy carbon electrode modified by C60 coat was used to mediate the oxidation
of cysteine in contact with an aqueous electrolyte containing potassium cation.
Under conditions of cyclic voltammetry, the potential of cysteine is lowered by
approximate 100 m V and current is enhanced significantly relative to the situation
prevailing when a bare glassy carbon electrode is used. Mediation also occurs
when the potential range covered include that of Cw/C60n- redox couples
