Properties of MZO/ceramic and MZO/glass thin layers based on the substrate's quality

To evaluate the role played by the substrates on the change and the actual difference of the studied samples on their structural, morphological, optical and photocatalytic properties, thin layers of zinc oxide grafted with magnesium were prepared with the same number of layers, doping ratio and experimental conditions with the use of two types of porous ceramic substrates and glassy. The XRD analysis detected the polycrystalline structure with wurtzite-type for all synthesized samples. The grain size was found to vary between 39 and 21 nm for DD3Z and 23 nm to 17 for glass. UV-visible absorbance data indicated that all MZO films absorb visible light at around 410 nm. In addition, a blue shift toward shorter wavelengths side was noted with increasing magnesium content up to 4 wt%, while the band gap showed an increasing trend achieving 3.07 eV for ceramics substrate. SEM analysis showed that the doping greatly affected the morphology of ZnO samples. Based on the results shown by the photocatalytic activities of orange II, the doping with magnesium gave a significant improvement to the samples with a ceramic substrate compared to the samples with a glass substrate. To reveal the mechanism of photolysis Hole/radical scavengers were used. It was found that the addition of Mg-ZnO networks increases the adsorption of hydroxyl ions on the surface and thus acts as a trap site leading to the reduction of hole/electron pair and thus increasing the activity and enhancing photodegradation.