Photocatalytic Enhancement of a Novel Composite CuAl2O4/TiO2/CuO Films Prepared by Sparking Process

A novel composite CuAl2O4/TiO2/CuO films were successfully deposited on quartz substrate using a simple and low-cost sparking process. The as-deposited films were then annealed at 300, 700 and 1100 degrees C for 1 h under atmospheric pressure. Morphology, structural and optical properties were characterized by SEM, TEM, XRD, XPS and UV/vis spectroscopy. The results show the nanoparticles with size of 20-50 nm deposited and aligned as a network on the substrate. The number of particles decreased with increased annealing temperature. Meanwhile, SAED and XRD patterns of the annealed films at 700 degrees C consisted of CuO, CuAl2O4 and rutile TiO2 phases. Interestingly, double band gap of 3.50 eV and 2.56 eV were obtained in the annealed films at 700 degrees C. The photocatalytic activity of CuAl2O4/TiO2/CuO films annealed at 700 degrees C was optimized condition. This is because the double band gap composite films can reduce the e(-)/h(+) pair recombination. Therefore, novel composite films after annealing at 700 degrees C can improve the photocatalytic efficiency under visible light.