Functional illite clay/nano-TiO ₂ composite mineral coating obtained by mechanical activation

Self-cleaning coatings have the potential to protect building material surfaces against the effects of climate change and air pollution. In this study, composite powders containing 3 and 10 wt-% nano-TiO 2 impregnated on mineral illite clay were synthesised by mechanical activation. The particle size distribution, mineralogical composition, and photocatalytic activity of the composite powders were characterised. A coating prepared from the 10 wt-% nano-TiO 2 /illite composite was applied to three different substrates (highly porous, porous and non-porous), and their surface properties, functional properties and durability were evaluated. The self-cleaning and photocatalytic activities of the coating were evaluated by measuring the initial contact angle and degradation efficiency, respectively. Rhodamine B was chosen as the model pollutant. The varying functional behaviours of the coating were analysed in relation to its structural, textural and morphological properties. The 10 wt-% nano-TiO 2 /illite coating exhibited pronounced hydrophilicity and demonstrated potential applicability for both porous and non-porous substrates.