Fast and Low-Temperature (70 °C) Mineralization of Inkjet Printed Mesoporous TiO2 Photoanodes Using Ambient Air Plasma.

Hybrid mesoporous titania/silica electron-generating and transporting layers were prepared using wet-coating with a dispersion consisting of prefabricated titania nanoparticles and a methyl-silica binder. Titania/methyl-silica wet layers were deposited by inkjet printing and further mineralized by low-temperature atmospheric-pressure air plasma using diffuse coplanar surface barrier discharge (DCSBD) to form a titania/silica hybrid nanocomposite coating. Morphological analysis performed by scanning electron microscopy revealed no damage to the titania nanoparticles and chemical analysis performed by X-ray photoelectron spectroscopy disclosed a rapid decrease in carbon and increase in oxygen, indicating the oxidation effect of the plasma. The coatings were further electrochemically investigated with linear sweep voltammetry and chronoamperometry. The magnitude of photocurrent and photocatalytic activity were found to increase significantly with the plasma exposure on the order of 10s of seconds. The results obtained demonstrate the potential of DCSBD ambient air plasma for fast and low-temperature mineralization of titania mesoporous coatings.