In Situ Spectroelectrochemistry and Electrochemical Quartz Crystal Microbalance (EQCM) Characterization of C60 Embedded in a Tetraoctylammonium Bromide Film in Aqueous Solution

The electrochemical behavior of C 60 embedded in tetraoctylammonium bromide (TOAB) films deposited on glassy carbon, quartz crystal microbalance (QCM) gold crystals, and indium tin oxide (ITO) electrodes was investigated in detail. Three reversible redox peaks were observed in aqueous solution. The first reduction peak for a C 60 −TOAB film in aqueous solution was found to be much more positive (500 mV shift) than that reported for C 60 in nonaqueous solution. In situ Vis/NIR spectra were recorded to monitor the electrochemical processes of C 60 −TOAB on the electrode surfaces. The results provide the first direct evidence for the generation of discrete monoanions and dianions of C 60 in the TOAB film in aqueous solution. The electrode processes were also monitored using electrochemical quartz crystal microbalance (EQCM) in different supporting electrolytes. Pronounced anionic effects due to diffusion into or out from the C 60 −TOAB films were also observed for first time.