Photo-corrosion inhibition and photoactivity enhancement with tailored zinc oxide thin films

► Preparation of ZnO, TiO2 and coupled ZnO/TiO2 thin films. ► Photocatalytic degradation of MB by ZnO, TiO2 and coupled ZnO/TiO2. ► Developed metabolites analyzed by using HPLC. ► Possible reaction pathways of MB degradation. The nanocrystalline ZnO, TiO2 and ZnO/TiO2 films are deposited onto FTO-coated glass substrates by using spray pyrolysis technique. The structural, morphological, optical and photoelectrochemical properties of the ZnO, TiO2 and ZnO/TiO2 are investigated by X-ray diffraction, scanning electron microscopy, UV–Vis spectroscopy and photoelectrochemical techniques. XRD analysis shows that films are polycrystalline and having hexagonal and tetragonal crystal structure for pure ZnO and TiO2. The photocatalytic degradation of methylene blue has been investigated with ZnO, TiO2 and ZnO/TiO2 photocatalysts. ZnO/TiO2 thin films have proved quite effective mineralization of methylene blue, while pure ZnO and TiO2 do not lead complete mineralization of methylene blue. The metabolites produced during degradation are analyzed by HPLC and Fourier transforms infrared spectroscopy. The by-products detected during degradation have been identified by GCMS technique.