Titania–lanthanum phosphate photoactive and hydrophobic new generation catalyst

Titania–lanthanum phosphate nanocomposites with multifunctional properties have been synthesized by aqueous sol–gel method. The precursor sols with varying TiO2:LaPO4 ratios were applied as thin coating on glass substrates in order to be transparent, hydrophobic, photocatalytically active coatings. The phase compositions of the composite powders were identified by powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM). The anatase phase of TiO2 in TiO2–LaPO4 composite precursors was found to be stable even on annealing at 800 °C. The glass substrates, coated with TL1 (TiO2–LaPO4 composition with 1 mol% LaPO4) and TL50 (composite precursor containing TiO2 and LaPO4 with molar ratio 1:1) sols and annealed at 400 °C, produced contact angles of 74° and 92°, respectively, though it is only 62° for pure TiO2 coating. The glass substrates, coated with TL50 sol, produced surfaces with relatively high roughness and uneven morphology. The TL1 material, annealed at 800 °C, has shown the highest UV photoactivity with an apparent rate constant, kapp=24×10−3 min−1, which is over five times higher than that observed with standard Hombikat UV 100 (kapp=4×10−3 min−1). The photoactivity combined with a moderate contact angle (85.3°) shows that this material has a promise as an efficient self-cleaning precursor.