Physical investigations on annealed structure Cu/La2O3 for photocatalytic application under sunlight

This paper deals with the synthesis of Cu/La2O3 thin layers and the effect of their surface defects in the photocatalysis process. First, La2O3 thin layers were obtained using pyrolysis technique by spraying at 460 degrees C on glass substrates. Then, 10 nm thick of Cu is deposited on the top of La2O3 layers by the thermal evaporation process. Finally, these layers are subjected to a heat treatment under air. In order to identify their structures and morphological properties, these layers were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscope. The optical and electrical properties of these layers were examined using photoluminescence and conductivity measurements, respectively. In addition, the photocatalytic activities of La2O3:Cu thin films were studied by monitoring the degradation of aqueous methylene blue under solar irradiation. It was found that the layer annealed for 2 h exhibited the highest photocatalytic activity. This fact can be explained by the enhancement of its structural and morphological properties.