Pulsed laser deposited Cu2O/CuO films as efficient photocatalyst

Cu2O and CuO films are deposited on a glass substrate by pulsed laser deposition (PLD) technique under different ambient environments and pressures. X-ray Diffraction and micro-Raman spectroscopy revealed that the films, synthesized at 2 Pa of N-2 ambient have Cu2O phase whereas the films synthesized at 2 Pa of O-2 ambient are of CuO. Field emission scanning electron microscopy shows uniform surface morphology of the samples with a film thickness of ~& nbsp;& nbsp;200 nm. Optical band gaps of the samples are measured from optical absorption spectra in the UV and visible region. The direct band gaps for the deposited films are estimated to be 2.45 eV and 2.25 eV corresponding to Cu2O and CuO phases respectively. Using these films, photo-catalysis of methylene blue (MB) dye was performed under direct sunlight. Remarkable efficiency having reaction rate constant of 0.020 min(-1) with good recycling ability is exhibited by the samples.