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 (C₆₀O_n)

In this letter, we present experimental data which challenges the model proposed since the mid-1990s that the reduction of C₆₀ films in aqueous electrolytes involves the formation of [M⁺_nC₆₀^n-] where M⁺ represents a metal cation or proton. Instead we provide voltammetric, XPS and UV–vis evidence that the reduction of “C₆₀” films in aqueous media is instead the reduction of adventitious poly-epoxidated C₆₀O_n with subsequent chemically irreversible loss of “O₂^-” as water, and that C₆₀ is not reduced within the potential windows of aqueous electrolytes.