Synthesis and structural characteristics of high surface area TiO₂ aerogels by ultrasonic-assisted sol–gel method

Abstract

TiO aerogel is a unique three-dimensional porous nano-particle material with the characteristics of high specific surface area and good light transmittance. In this paper, a novel method involving ultrasonic-assisted sol-gel, solvent exchange, and vacuum drying was successfully developed to synthesis the TiO aerogel. The morphology and properties of the prepared TiO aerogels were characterized by the Brunauer-Emmett-Teller theory (BET), x-ray diffraction, field-emission scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis-differential thermal analysis, Fourier transform infrared spectroscopy, and Raman spectroscopy. The adsorption and photocatalytic activity of TiO aerogels was evaluated by monitoring the degradation of Rhodamine B solution. Our results indicated that: (1) with an optimum ratio of Ti:HO = 8:1 the BET surface area, average pore diameter, and total pore volume of TiO aerogel are enhanced to 563.6 m g, 3.01 nm, and 0.42 cm g, respectively; (2) the TiO aerogels possessed controllable crystal form depending on the thermal treatments conditions. The crystal face (101) of anatase, complete anatase, mixed state of anatase and rutile, and rutile were obtained by increasing the temperature from 200 °C-300 °C, from 400 °C-500 °C, 600 °C, and from 700 °C-1000 °C, respectively; and (3) the excellent catalytic activity of the as-prepared TiO aerogels for the ultraviolet photolytic degradation of Rhodamine B had attributed to the synergistic effect of adsorption and photoactivity.

Rapid preparation of terbium-doped titanium dioxide nanoparticles and their enhanced photocatalytic performance

“…As shown in figure 5, the photocatalytic activity first increased and then decreased as the Tb doping amount from 0 to 2.0%, and the sample with Tb doping amount of 1.0% exhibited the highest photocatalytic activity, which was consistent with the results of UV–Vis DRS. In most cases, the efficiency enhanced with the increase in Tb doping amount, owing to sufficient photo-induced carrier trapping centre generated in the catalyst lattice surface layer [29]. However, if the Tb doping amount was too high, a large number of defects and excessive oxygen vacancies caused by lattice distortion would result in the recombination of holes and electrons.…”

“…Thereafter, turning on the mercury lamp to carry out the photocatalytic reaction, 5 ml of the suspension was collected every 0.5 h. Finally, the suspension was centrifuged to remove the catalysts, and the supernatant was taken to measure the absorbance at 662 nm by a UV–visible spectrophotometer. The degradation rate was calculated by the following formula [29] η=C0−CtC0×100%.where C 0 was the concentration of the original solution and C t was the concentration of solution at specific time intervals.…”

Synthesis of Monolithic TiO2 Aerogels With Relatively Low Shrinkage and Improved Formability Assisted by CTAB

“…Studies show that the calcination temperature obviously effects the phase formation (Qin et al, 2013;Zirakjou et al, 2015;Topcu et al, 2016). With ethanol as the solvent, it is amorphous TiO 2 aerogel if the calcination temperature is below 200°C (Qingge et al, 2018). Normally, the temperature should be above 450°C to obtain anatase TiO 2 .…”

“…To improve the photocatalytic effect, TiO 2 powder doped into different materials was discussed in previous studies (Anucha et al, 2021;Bathula et al, 2021). As aerogel is a kind of material with high specific surface area and large porosity (Wen et al, 2018;Yan et al, 2018;Bi et al, 2019;Wen et al, 2020), it is a better choice to study the photocatalysis of TiO 2 aerogel (Moussaoui et al, 2017;Qingge et al, 2018;Zhang et al, 2018). However, it is tough to prepare a kind of TiO 2 aerogel with low density and high porosity.…”

Preparation and Photocatalytic Water Splitting Hydrogen Production of Titanium Dioxide Nanosheets

“…Compared to the lamellar structure, the granular aggregates contained hydrates and bulk anatase crystal phase TiO 2 . These are not conducive to the production of hydrogen from the photolysis of water, and this may be because the granular and massive morphology greatly reduces the specific surface area of the sample and blocks the active surface [31,32].…”