Chemical modification and electrochemical behaviour of graphite fibre in acidic vanadium solution

Abstract Residual graphite oxide fibres (rGo fibres) were prepared by electrochemical oxidation and partial reduction of a graphite fibre electrode with a slow linear potential sweep in 97% H 2 SO 4 solution and then metallized by impregnation or ion-exchange with solutions containing Pt 4+ , Pd 2+ , Au 4+ , Mn 2+ , Te 4+ ,In 3+ and Ir 3+ . The cyclic voltammetry of the modified electrode in an acidic vanadium sulphate solution showed that the electrode modified by Pt 4+ exhibited electrochemical behaviour consistent with a Pt electrode in the same solution. High hydrogen evolution rates were obtained on Pt, Pd, and Au modified electrodes while the electrode modified by Ir 3+ exhibited the best electrochemical behaviour for the various vanadium redox species. The electrodes treated with Mn 2+ , Te 4+ and In 3+ gave similar cyclic voltammetric behaviour with significantly improved electrochemical activity compared with the untreated fibre electrode.