Morphological, optical, catalytic and photocatalytic properties of RF magnetron sputtered Au-Cu2O-CuO nanocomposite thin films

Plasmonic nanocomposite thin films represent an important set of materials which has gained huge attention for photocatalytic and catalytic applications. We report on fabrication of thin films of Au-Cu2O-CuO nanocomposites by RF magnetron co-sputtering which were thoroughly analyzed by atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis-DRS, UV-vis absorption and photoluminescence spectroscopy (PL). AFM and FESEM analyses revealed nanoparticle growth with increase in Au content of the nanocomposite. XPS analysis revealed the existence of Au, Cu2O and CuO in the obtained films. The prepared nanocomposite thin film demonstrated excellent sunlight driven photocatalytic performance for the degradation of organic pollutants and significant catalytic activity for the transformation of 4-nitrophenol (4-NP). Au-Cu2O-CuO nanocomposite thin film removed 73.1% of methyl orange (MO) and 86.2% of methylene blue (MB) in only 28 min of solar exposure. Improved visible light absorption together with better charge separation and improved transport of charge carriers due to Au nanoparticles embedded in Cu2O-CuO thin film significantly improved the catalytic and photocatalytic features of the nanocomposite. The reusability and role of radicals in the photocatalysis for Au-Cu2O-CuO nanocomposite thin film are also highlighted.