Electrochemical nanostructuring of fullerene films—spectroscopic evidence for C60 polymer formation and hydrogenation

Abstract

Electrochemical reduction of ordered C60 fullerene films in aqueous solution was studied by AFM, FTIR and Raman spectroscopy, mass spectrometry and elastic recoil detection analysis. During the irreversible reduction process the film morphology changed from a heteroepitaxial (111) surface to a nanostructured array with clusters of 20 to 50 nm lateral size on average. On the molecular level the initial C60 underwent electrochemical reactions to form C60 polymers and hydrogenated C60. Chemical follow-up reactions of electrochemically formed C60- with water are responsible for the different reduction behaviour of C60 films in aqueous solution compared to C60 reduction in organic solvents and to C60 doping with alkali metals. Based on the spectroscopic analysis a reaction scheme accounting for the chemical processes at the C60 / aqueous electrolyte interface is presented.

Electrochemistry of symmetrical fullerene dimer C121 film modified electrodes

“…SEM image shows that the sizes of average diameter of the balls turn to be smaller and more homogeneous, and it is estimated to range from 0.277 ± 0.02 to 0.16 ± 0.01 lm, which indicates a structural rearrangement during the electrochemical scan. This is similar to that of C 60 films [38]. Upon reduction, chemical follow-up reactions of electrochemically formed anion with water attributed to the different reduction behavior of C 121 films in an aqueous solution compared to the reduction of C 121 films in organic solvents mentioned above.…”

The electroreduction of “C60” films in aqueous electrolyte does not lead to alkali metal ion insertion—Evidence for the involvement of adventitious poly-epoxidated C60 (C60On)

“…The much cited cation insertion mechanism has also been recently challenged by Dunsch and coworkers [23] who also found no evidence of cation insertion, and instead proposed a C 60 polymerization mechanism with concomitant protonation. Although the mechanism, as proposed by Dunsch et al is not charged balanced in their paper, it is not inconsistent with the results presented herein so far.…”

Spectroelectrochemistry of Carbon Nanostructures

“…The attenuation of the A g (2) mode is apparent, along with the growth of orthorhombic polymer o ‐C 60 155. 156 In situ Raman spectroscopy has shown that both polymerization and hydrogenation of the fullerenes occur 156. On the other hand, in ionic liquids (cf.…”

“…Section 4) the charged fullerenes react with the alkyl group of imidazolium cation 155. Furthermore, IR‐spectroscopy was used to study the chemical reaction products of the fullerene,156, 157 especially if the fullerene is used in thin layers together with organic polymers 158. 159 Therefore vibrational spectroscopy is a preferable technique in electrochemical studies of nanocarbon.…”