Irena Kozjek Škofic

CeO2 thin films obtained by sol–gel deposition and annealed in air or argon

Abstract Thin films of CeO 2 were prepared on SnO 2 /F-coated glass plates by the sol–gel dip-coating process using CeCl 3 ·7H 2 O as a precursor. The films were heat-treated in an air or argon atmosphere. The structural, electrochemical and optical properties of these films depend on the preparation conditions. Transmission electron microscopy (TEM) showed the films to be polycrystalline with randomly orientated crystallised domains of up to 10 nm in size. The degree of crystallinity of films heat-treated in argon is higher than that of those heat-treated in air, and therefore their charge capacity values (15.9 mC cm −2 after 100 cycles) and reversibility of the ion-storage process (0.99 after 100 cycles) are higher than for films heat-treated in air (10.5 mC cm −2 and 0.86 after 100 cycles, respectively). Both films are optically passive under Li + ion insertion and have high optical transmittance (>80%).

A novel method for preparation of a platinum catalyst at low temperatures

Uniformly distributed Pt nano-particles with excellent adhesion were deposited on conductive substrates by coating the substrate with a Pt complex precursor and its subsequent reduction with a gaseous reducing agent at temperatures as low as 100 °C. This novel two-step method enables excellent control over the particle size and distribution since it is dependent only upon the deposition of the precursor solution, and there is little to no agglomeration or movement of Pt nano-particles during the reduction process. The good adhesion was the result of the reaction at the solid–gas interface, where the solid precursor was chemically converted to metallic Pt. XPS confirmed that 100% of Pt was in the metallic state. The electrochemical catalytic properties of the Pt nano-particles were tested using cyclic voltammetry in an iodide electrolyte. The prepared samples were also used to assemble dye-sensitised solar cells that achieved a light to electricity conversion efficiency of 5.1% under AM 1.5 illumination.