Étude de l’effet de quelques paramètres sur l’électrodéposition des oxydes TiO2 et ZnO et leurs applications dans la dégradation photocatalytique de colorants

Abstract

In this work, we developed semiconductor thin films of zinc oxide (ZnO), and titanium dioxide (TiO2), on the conductive glass (FTO), for photocatalytic application, by cyclic voltammetry and chronoamperometry, from solutions whose physicochemical parameters are different. The structural characterization by XRD reveals the hexagonal structure, Würtzite type, for the ZnO layers, and the tetragonal structure, anatase type, for the TiO2 layers. The micrographic analysis by SEM reveals the formation of deposits consisting of nanometric grains of shapes dependent on the processing conditions for ZnO; moreover the TiO2 layers exhibit rather a compact shape. The roughness and symmetry of the different films were demonstrated by the AFM. The study of photoelectrochemical performance evaluated by several techniques was able to highlight the photoactivity of these materials, by displaying a strong anodic photocurrent and thus confirms the n-type semiconductor nature of our electrodes. The flat band potential and the donor density are calculated. Finally, tests of degradation of some dyes on certain deposits, under solar radiation and under a UV source, demonstrated similar activities, relatively low, given that the small surfaces used.