Laser-assisted photocatalysed degradation of pollutants using semiconductors in electronic contact with gold nanoparticles
Résumé
Metal oxide semiconductors hold great promise for applications in energy conversion and storage, environmental remediation, and other areas. However, critical factors such as the high rate of charge-carrier recombinations and limited light absorption have restricted more practical and viable applications (Saji et al, 2013). Plasmonic nanostructures of noble metals have been attracting significant attention for their ability to interact with light from visible to near IR range through the creation of resonant surface plasmon (Stewart et al, 2008). Plasmonic nanostructures of noble metals in combination with semiconductors offer a promising future for the next generation of energy needs. Various methods have been described for the synthesis of TiO2 and metal nanoparticles hybrid. In this study, GNPs were fabricated in a thin film of nanocrystalline TiO2 by sol-gel spin coating method. The thickness can be adjusted by repeating the cycle from adding the Titanium alkoxide precursor on the substrate after calcination at 450˚C. The morphology of the nanocomposite and the phases of the films were determined by SEM and Raman. The interaction with noble metal and semiconductor nanostructures under visible light is investigated. Particularly, we study the photocatalytic degradation of Methylene Blue (BM) and Bisphenol A (BPA) under visible light using Au-TiO2 and Au-ZnO as photocatalysts. Green laser emitting at 532 nm was used to excite the resonance band of the GNPs. The influence of various parameters such as irradiation time, laser power, and catalyst type and amount has been studied.