Double layer capacitance of Pt(111) single crystal electrodes

In order to determine the double layer capacitance of the Pt(111) electrode , impedance and capacitance measurements were carried out in neutral and ac idic aqueous perchlorate solutions. Separation of the double layer and adso rption contributions of the interfacial capacitance were based on the adsor ption impedance theory. The double layer capacitance versus potential plot exhibits a peak at about 0.12 V versus SCE in the 1.5-7 pH range; from here towards cathodic potentials the capacitance attains a value of about 20 mu F/cm(2). The peak may be related to the potential of zero free charge of th e Pt(111) electrode. (C) 2001 Elsevier Science Ltd. All rights reserved.