Characterisation and application of a novel cell for mechanistic electrochemistry at elevated temperatures

Abstract

A novel high temperature cell capable of measuring electrochemical signals up to temperatures of 115 °C is reported. Characterisation of the cell has been undertaken by examining three differing systems. First the voltammetric response of a range of simple redox systems in both aqueous and non-aqueous media was recorded in order to deduce the activation energies for diffusion of these molecules. Next the steady state linear sweep voltammetric response of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) in dimethyl sulfoxide (DMSO) is assessed as a means of studying an inferred structural change of the solvent at elevated temperatures. A change in the activation energy for diffusion from 13 kJ mol⁻¹ to 27 kJ mol⁻¹ was observed as the temperature was raised. Finally, the electrochemically catalysed reaction of the radical cation TMPD⁺˙ with ascorbic acid is studied from 25 °C to 107 °C; the corresponding kinetic parameters are deduced.