Glassy carbon electrodes: I. Characterization and electrochemical activation

Abstract Electrochemical properties of glassy carbon electrodes of two types were examined, one thermally treated at 1000°C (sample K) and another thermally treated at 2500° (sample G). Mechanically polished or electrochemically polarized electrodes were characterized in NaOH, HClO4 and H2SO4 solutions by cyclic voltammetry (cv) at different sweep rates in the potential range between the hydrogen and oxygen evolution. The activity of the electrodes depended on the properties of the glassy carbon examined, as determined by both the temperature of thermal treatment and the mechanical or electrochemical pretreatment of the sample. It was noticed that both types of electrodes, when polished exhibited an increase in the double layer charge upon increasing the pH value of the solution. The cv charges, for both types of samples, increase upon anodic polarization. The higher the potential of oxidation, the more pronounced is the increase in charge, particularly in acidic solution. The increase in charge amounts from below 1 mC cm−2 for polished glassy carbon up to few hundreds of mC cm−2 for surfaces anodically polarized in acidic solution. Analysis of the dependence of voltammetric charge, as well as morphological changes of the electrode surface, on the time of oxidation suggests the existence of three stages in the electrochemical activation process. The first one occurs only once at the beginning of the activation, while the other two repeat themselves, reflecting a periodical activation and deactivation process. These stages were discussed and ascribed to a surface layer oxidation, graphite oxide layer growth and mechanical destruction of the surface. Independent surface analysis by AES, XPS and STM confirms the results obtained by electrochemical methods.

[1]  T. Kuwana,et al.  Activation and deactivation of glassy carbon electrodes , 1985 .

[2]  W. Smyrl,et al.  Surface modification and oxygen reduction on glassy carbon in chloride media , 1989 .

[3]  I. Casella,et al.  Controlled chemical oxidation of carbon fibres: An XPS–XAES–SEM study , 1993 .

[4]  T. Kuwana,et al.  Considerations for polishing glassy carbon to a scratch-free finish , 1985 .

[5]  R. Engstrom,et al.  Characterization of electrochemically pretreated glassy carbon electrodes , 1984 .

[6]  D. D. MacNeil,et al.  Comparison of the Reactivity of Various Carbon Electrode Materials with Electrolyte at Elevated Temperature , 1999 .

[7]  R. Kötz,et al.  IN SITU ATOMIC FORCE MICROSCOPY OF ELECTROCHEMICALLY ACTIVATED GLASSY CARBON , 1999 .

[8]  Yong Yang,et al.  In situ FTIR characterization of the electrooxidation of glassy carbon electrodes , 1995 .

[9]  K. Stulík,et al.  The use of platinum and carbon indicator electrodes in acid-base titrations , 1968 .

[10]  S. Biniak,et al.  Cyclic voltammetric studies of chemically and electrochemically generated oxygen species on activated carbons , 1997 .

[11]  Allen J. Bard,et al.  Electroanalytical Chemistry: A Series of Advances , 1974 .

[12]  Yong Yang,et al.  IN-SITU IR SPECTROSCOPIC CHARACTERIZATION OF SURFACE OXIDE SPECIES ON GLASSY-CARBON ELECTRODES , 1994 .

[13]  P. Anantharaman,et al.  Voltammetric studies on glassy carbon electrodes I: Electrochemical behaviour of glassy carbon electrodes in H2SO4, Na2SO4 and NaOH media , 1986 .

[14]  V. J. Jennings,et al.  Oxidized vitreous carbon indicator electrodes in acid-base titrations , 1974 .

[15]  A. Ishitani,et al.  XPS study of the carbon fiber matrix interface , 1990 .

[16]  K. Kawamura,et al.  Structure of Glassy Carbon , 1971, Nature.

[17]  J. Jordan,et al.  Voltammetry at glassy carbon electrodes , 1984 .

[18]  A. Bard,et al.  Ellipsometric, electrochemical, and elemental characterization of the surface phase produced on glassy carbon electrodes by electrochemical activation , 1988 .

[19]  W. E. Van Der Linden,et al.  Glassy carbon as electrode material in electro- analytical chemistry , 1980 .

[20]  G. Korshin.  Investigation of the oxidation of glassy carbon by the method of electroreflectance—relevance to activation processes , 1998 .

[21]  Honghua Zhang,et al.  Effects of high-intensity ultrasound on glassy carbon electrodes , 1993 .

[22]  Z. Laušević,et al.  Anodic oxidation of glassy carbon surfaces , 1986 .

[23]  R. Reeves,et al.  Interaction of glassy carbon with electrolyte and hydrogen, and the influence of these processes on the emission of electrons☆ , 1984 .

[24]  Ernest Yeager,et al.  Differential capacitance study on the edge orientation of pyrolytic graphite and glassy carbon electrodes , 1975 .

[25]  J. Veselý,et al.  The potentiometric response of some carbonaceous electrodes , 1973 .

[26]  H. Fritz,et al.  The Electrochemistry of Black Carbons , 1983 .

[27]  P. Upadhyay.  A simple procedure for activating a glassy carbon electrode , 1989 .

[28]  R. McCreery,et al.  In situ laser activation of glassy carbon electrodes , 1986 .