Electron-Transfer Kinetics of Quinones at Solid Electrodes in Aprotic Solvents at Low Temperatures

Article abstract of DOI:10.1021/j100257a039

Activation paramaters for the electrochemical one-electron reduction of quinones were evaluated at glassy carbon, Au, and Pt electrodes from 170 to 290 K in aprotic solvents (N,N-dimethylformamide and propionitrile) by cyclic voltametry.Systematic differences in the activation parameters among electrode materials were observed.The average of the activation enthalpy was 13 +/- 2 kJ /mol for the glassy arbon electrode, 21 +/- 3 kJ/mol for the Au electrode, and 14 +/- 4 kJ/mol for the Pt electrode in N,n-dimethylformamide, showing that the extent of the interaction between the electrode surface and the reactant is different for each electrode material.The Arrheneus plots for 1,4-benzoquinone curved down only at the glassy carbon electrode in both N,N-dimethylformamide and propionitrile, indicating that it was reduced by a different mechanism at law temperatures (<250 K) at the glassy carbon electrode.The experimental techniques and a simple cooling system for low-temperature electrochemistry are also described.