Structural and electrochemical investigations of Ce/Cu mixed oxide thin films

Thin films of Ce/Cu mixed oxide with molar ratios of 1 and 2 were prepared from inorganic precursors using the sol–gel route. Various electrochemical and spectroscopic techniques were used for characterization of the films and investigation of their optical and electrochemical properties. It was found that the redox behaviour significantly depends on the Ce/Cu ratio and on the concentration of Li+ ions. Slow kinetics of the charge transfer reactions was evident from cyclic voltammetry measurements of both types of films only at low scan rates (<20 mV/s). Measurement of X-ray absorption fine structure (XAFS) indicated that the local structure of Ce and Cu ions is not affected by the Ce/Cu molar ratio.