Hydrophobic, Photoactive Titania–Alumina Nanocrystallites and Coatings by an Aqueous Sol–Gel Process

Abstract

Hydrophobic coatings of titania-alumina nanocrystallites showing enhanced photocatalytic activity under sunlight were synthesized by an aqueous sol-gel route from titanyl sulfate. The influence of the addition of alumina in the range 5-30 mol-% on the phase transition and grain growth of nanocrystalline titania was investigated. A titania-alumina composition containing 5 mol-% Al 2 O 3 (TA-5), annealed at 700°C, showed the highest photocatalytic activity among all investigated compositions. While pure titania in the present study started to transform to rutile at 700°C, all the titaniaalumina compositions retained 100 % anatase phase up to 800°C. The specific surface area was measured as 73 m 2 g -1

Controllable synthesis and photocatalytic activity of spherical, flower-like and nanofibrous bismuth tungstates

“…If pH value is higher than 11.8, the newly formed Bi 2 O 2 (OH)NO 3 will react with OH − and WO 4 2− , which results in the formation of Bi 14 W 2 O 27 crystals as the impurity and has been demonstrated by Patzke's group [31]. The pH values below 11.8 favor the formation of the Bi 2 WO 6 phase.…”

“…During the past several decades, the thoroughly studied conventional TiO 2 has displayed excellent activities and stabilities [2][3][4]. However, the deficiency of requiring UV light for effective photocatalysis severely hinders the overall process to be used in practical.…”

Optical Properties of Rare‐Earth Doped TiO2 Nanocomposites and Coatings; A Sol‐Gel Strategy towards Multi–functionality

“…The photocatalytic activity of TiO 2 is known to depend on the oxygen vacancy concentration and oxygen mobility . Thus by integrating the outstanding optical properties of terbium ions and photoactive titania nanoparticles in a nanocomposite, there is excellent possibility to develop novel self‐cleaning green emissive phosphors in the form of coatings or thin films. Further, codoping of rare‐earth elements is reported to enhance the photocatalytic and luminescent properties.…”

Bentonite-titanium dioxide functional nanocomposites suitable for wastewater treatment: an integrated photocatalyst-adsorbent system

“…Type IV adsorption-desorption isotherms with a hysteresis loop indicating the mesoporous nature of the nanocomposites are revealed from the BET surface area analysis. 44 A bimodal pore size distribution curve was obtained for the samples analyzed with a small, but narrow peak at around 5 nm which is characteristic of bentonite clay. 45 A major peak centred at around 10-15 nm was observed for all the nanocomposites (BT-0.25, BT-0.5 and BT-1) whereas it was absent in the case of commercial titania containing nanocomposites.…”