Preparation of a porous nanocrystalline TiO2 layer by deposition of hydrothermally synthesized nanoparticles

In this work, a porous nanocrystalline anatase TiO2 layer is prepared by tape casting a viscous dispersion of nanoparticles. Phase pure anatase titanium dioxide nanoparticles with a particle size of 10–20 nm are prepared by a very simple low temperature (100 °C) hydrothermal synthesis route in a pressure vessel, using only water as the medium and Ti(IV)-isopropoxide as starting material without additives. The size, shape and phase composition of the particles are studied by means of X-ray diffraction and transmission electron microscopy. A dispersion of the as-prepared nanoparticles with a narrow particle size distribution, confirmed by photon correlation spectroscopy, is prepared. After increasing the viscosity of this dispersion by addition of hydroxypropyl cellulose, anatase titanium dioxide layers are tape cast on a transparent conducting metal oxide substrate. Pores are induced by burning out the organic additive at 450 °C. The morphology and the final phase composition of the deposited TiO2 layers are examined by X-ray diffraction and scanning electron microscopy.