Photocatalytic Degradation of Orange II by Active Layers of Ag-Doped CuO Deposited by Spin-Coating Method

For water purification in our daily life at low cost and in the goal to study the effect of doping elements for heterogeneous photocatalysis application, thin layers of Ag doped CuO, (5, 15, 25 and 50 wt.%) were prepared by a sol-gel method on a glass substrate for photocatalysis. The structural, morphological, optical and electrical characteristics of these layers have been studied. The results of X-ray diffraction (XRD) proved that there was a monoclinic phase structure in the direction (-111). This result indicated that thin films are polycrystalline. It was confirmed by infrared spectra (IR). In the case of Ag doping, scanning electron microscope (SEM) revealed a change in the shape of the granules with large and inhomogeneous sizes. Granules were spherical in the case of pure copper oxide. The energy gap decreases from 2.17 eV to 1.25 eV with the increasing doping. The improved capacitance is explained in terms of Ag particles present in CuO nanostructures giving a good electrical conductivity. The doping effect of Ag ions has improved the photocatalytic property of the CuO. It was tested for organic dye cleaning with Orange II. In addition, the presence of pores on the surface of Ag:CuO thin films and a reduce energy gap enables the creation of a greater number of center dot O and center dot OH that leads to eliminate the dye and give a transparent solution. A 50 wt.% Ag doping showed a high photoactivity (43%)after 5h compared to a pure CuO thin film (27% of degradation rate) for the same time.