Highly photoactive anatase foams prepared from lyophilized aqueous colloids of peroxo-polytitanic acid

Photocatalytic degradation of bisphenol A induced by dense nanocavities inside aligned 2D-TiO2 nanostructures

“…), 650 °C (Figure 5b/inset) and 800 °C (Figure 5c/inset) are indexed on the basis of the tetragonal anatase TiO 2 with space group I4 1 /amd and lattice parameters a = b = 0.378 nm and c = 0.951 nm (ICDD PDF 21-1272). These results are in agreement with previously reported observations[29,36,51] and are complemented by XRD measurements. The measured interlayer spacing was found to be d (101) = 0.352 nm for samples TiO_LYO_500 and TiO_LYO_650 (see HRTEM micrographs presented inFigures 4a2 and 4b2).…”

“…Despite its wide and increasing usage, many (nano)materials laboratories, especially these focusing on biopharmaceuticals,still think of freeze-drying as a complicated and sophisticated technology. A few years ago, our group reported improved properties of TiO 2 photocatalysts obtained by cryo-lyophilisation technique, but no attention was paid on the nanocavity phenomena [29]. Herein, we use cryo-lyophilization methodology as a novel and original non-standard green concept for the synthesis of ultrafine precursors containing aqueous colloids of peroxo-polytitanic Ti (IV) acid (PPTA).…”

“…The synthesis of 2D TiO 2 nanosheets was performed by the freeze-drying method and the experimental procedure is shown in Figure 1. The PPTA precursor was synthesized as described in previous publications [29,36]. Briefly, an aqueous solution of 4.8 g TiOSO 4 in 150 mL H 2 O was cooled under stirring untill floating ice crystals were formed.…”

“…where C and C 0 are BPA concentrations at time t and t = 0, respectively, and k is the pseudo-first-order kinetic rate constant [47,48]. According to previous studies [29,36] Table 1). The samples TiO_LYO_500, TiO_LYO_650, TiO_LYO_800, TiO_LYO_950 are very pure and contain only Ti and O ( Figure S1).…”

“…The crystallization takes place only in 2D direction while the lamellar structure with different degrees of crystallinity is preserved. Such morphology has the advantage of preventing agglomeration and thus enables the formation and preservation of a high surface area[29,36]. The branching phenomenon of TiO 2 nanosheets is registered at the temperature of 950 °C (Figure 3f); the lamellar morphology partly collapsed since anatase-rutile transformation took place (see XRD part and…”