Cyclic voltammetry on recessed nanodisk-array electrodes prepared fromtrack-etched polycarbonate membranes with 10-nm diameter porest

摘要

This paper described cyclic voltammograms (CVs) on a recessed nanodisk-array electrode (RNE)prepared from a track-etched polycarbonate membrane (TEPCM) with 10-nm diameter pores. A RNEwas prepared via sputtering of a gold thin film onto a TEPCM whose pores were coated withpolyvinylpyrrolidone. CVs of such a RNE changed from peak-shaped to sigmoidal with decreasingscan rate due to the transition of diffusion modes of redox-active molecules, as with previous reports.However, faradic currents in these CVs were larger than theoretical currents calculated from themembrane thickness, pore density, and pore diameter. The larger faradic currents may reflect thepresence of a surface layer on TEPCM nanopores to which the redox species preferentially distribute ascompared with the nanopore cavity. The limiting current of uncharged 1,1'-ferrocenedimethanol wasnot affected by solution pH or supporting electrolyte concentration. In contrast, those of anionicferricyanide and cationic ferrocenylmethyltrimethylammonium decreased and increased, respectively,with increasing pH from 4 to 9. These pH-dependent changes in limiting current were larger at lowersupporting electrolyte concentration. The dependence of the CVs on solution pH and supportingelectrolyte concentrations was attributed to electrostatic interaction between the redox species and thecharged TEPCM nanopores.