Fabrication, characterization and photocatalytic activity of TiO2 layers prepared by inkjet printing of stabilized nanocrystalline suspensions

Abstract

Titanium dioxide (TiO2) colloidal dispersions were synthesized by hydrothermal synthesis in acidic pH under various process conditions. Phase structure of prepared TiO2 was identified as pure rutile by X-ray diffraction analysis and crystallite sizes determined by the Scherrer equation were in the range of 10–25nm. These values correlated with particle sizes observed by transmission electron microscopy (TEM). Afterwards, the prepared TiO2 dispersions were used for the formulation of stable inkjet printable “inks”. Thin layers of nanocrystalline TiO2 were deposited by inkjet printing onto soda-lime glass substrates. After sintering at 500°C, thin patterned films were obtained. Their basic physicochemical properties were characterized by standard methods. Optical microscopy and SEM imaging revealed highly structured topography of samples surface. Layer hardness was equivalent to the B pencil as determined by the “Pencil Hardness Test”. The topology and roughness were examined by atomic force microscopy and RMS roughness was in the range of 40–100nm. Band gap energy of TiO2 determined by UV–vis reflection spectroscopy was consistent with known rutile values. The photocatalytic activity of printed layers was evaluated on the basis of 2,6-dichloroindophenoldiscoloration rate monitored by UV–vis spectroscopy and did not exceed the performanceof Aeroxide P-25. Despite average photocatalytic performace of this particular TiO2 type, inkjet printing proved to be an efficient method for the fabrication of patterned titania films originating from nanocrystalline precursor.