Synthesis of NiO and NiO/TiO2 films with electrochromic and photocatalytic activities

NiO and NiO/TiO 2 films were prepared on fluorine doped tin oxide (FTO) coated glass substrates by electrochemial deposition and sol–gel method. Choline chloride–urea ionic liquid was used as electrodeposition media. The composition, morphology and microstructure of the films were characterized by a scanning electron microscope (SEM) and X-ray diffractometer (XRD). Cyclic voltammetry (CV), cycle life, response time and transmittance of the films were measured and compared with each other. Photocatalytic activity of the NiO/TiO 2 film was examined and explained through the degradation of methyl orange. Results show that, after 8000 cycles, both NiO and NiO/TiO 2 films still maintain their good electrochromic property and stability. The NiO/TiO 2 film not only performs excellent electrochromic function but also displays a certain photocatalytic activity. And interestingly, the NiO/TiO 2 film at bleached and colored states demonstrates different photocatalytic activities, which are higher than that at as-prepared state.