Characterization of Different Types of Screen-Printed Carbon Electrodes Modified Electrochemically by Ceria Coatings

Electrochemical formation of ceria (mixed Ce2O3 and CeO2) coatings on different types of screen-printed carbon electrodes (SPCEs) (based on: graphite (C110); carbon nanotubes (CNT); single-walled carbon nanotubes (SWCNT); carbon nanofibers (CNF) and mesopo-rous carbon (MC)) have been studied. This study was in order to elucidate their potential possibilities for application as catalytic active systems for different types of oxy-reduction reactions (as well as their exploitation as high resolving electrochemical sensors). The ce-ria layers have been electrodeposited on SPCEs in solutions based on abs.C2H5OH con-taining CeCl3x7H2O. Galvanostatic deposition of ceria coatings have been realized at dif-ferent current density and deposition time. The morphology, structure and chemical composition in the bulk of the ceria layers have been studied by SEM and EDS methods. By XRD the formed phases were observed. The concentration, chemical composition and chemical state of the elements on the surface of studied samples have been characterized by XPS. It is established that the increase of the concentration of CeCl3 in the working elec-trolyte and the cathode current density can lead to strong change of the surface structure and concentration (relation between Ce3+ and Ce4+, respectively) in the formed ceria layers. With a higher porosity are characterized the samples obtained at a low concentration of CeCl3 and low values of cathode current density. With their increase, ceria coatings grow more dense.