In situ atomic force microscopy of electrochemically activated glassy carbon

Glassy carbon (GC) electrodes were activated by anodic oxidation at a potential of 1.95 V standard calomel electrode in 1 M H2SO4. The activated electrodes were investigated by in situ contact atomic force microscopy. In order to monitor differences between activated and nonactivated areas, part of the electrode surface was covered by a polymeric varnish during electrochemical activation. The edge between activated and nonactivated regions was analyzed after removal of the varnish. The surface of the activated region was significantly higher than that of the nonactivated region, indicating significant swelling of the GC during anodic oxidation. After drying, the activated film collapsed. Swelling of the activated layer was a linear function of activation time and depended on the state of the electrode. In the oxidized state the film thickness was larger than in the reduced state. (C) 1999 The Electrochemical Society. S1099-0062(98)08-111-5. All rights reserved.