The Influence of the Precursor’s Nature and Drying Conditions on the Structure, Morphology, and Thermal Properties of TiO2 Aerogels

Abstract

A cost-effective solution for the synthesis of high-porosity TiO2 aerogels, which can be used as a mesoporous perovskite network charge-carrier material during the manufacture of solar cells, is described. The effects of the synthesis parameters (precursor (titanium (IV) isopropoxide (TIP) and tetrabutyl orthotitanate (TBOT)), additional solvent exchange (n-hexane (nH), cyclohexane (CH), and diethyl ether (DE)), subcritical drying (800 mbar vacuum, 70 °C, 8 h), aging, and calcination on the aerogel’s structure have been investigated. Methods of XRD, FT-IR, BET, Raman, STA, SEM, UV–vis, and thermal conductivity measurements were applied to find out the relation between the synthesis conditions and the properties of the synthesized aerogels. Amorphous aerogels are polydispersed systems with the highest probability of pore diameter from 0.5 to 15 nm. An nH-exchanged, aged aerogel synthesized from the precursor TIP shows the highest diameter of pores. After calcination, the aerogels tend to crystallize into an anatase phase and the size of the crystallites depends on the precursor’s nature. Calcination leads to a significant increase in both the apparent and true density of the aerogels, and it also results in an increase in porosity and thermal conductivity.

Silica Gels Doped with Gold Nanoparticles: Preparation, Structure and Optical Properties

“…The trend of increasing thermal conductivity due to AuNPs is in agreement with the results published in [ 26 ] for gold colloidal suspensions, where an increase in thermal conductivity in the range of 1–2% was reported. An increase in the thermal conductivity in TiO 2 aerogels due to an optical band gap decrease was demonstrated recently [ 27 ].…”

“…The silica gel micropowders containing AuNPs are stable up to 60 °C, which is suitable for possible drug carrier applications. Processes typical of sol-gel powders take place, i.e., dehydration (physically bonded water) followed by decomposition (chemically bonded water), organic modifier decomposition and their chemical reaction with the silica matrix, at temperatures above 200 °C [17,27,36]. AuNPs; oleic acid used as organic modifier).…”

Theoretical Study of the Impact of Pore Size in TiO₂ Aerogels on Photocatalytic Formaldehyde Decomposition

“…Among these common strategies, the sol-gel method has received the most widely studied. The pore size and specific surface area of TiO2 aerogels prepared by sol-gel method are affected by many factors, such as the concentration of precursor solution [58,59], preparation conditions (including temperature [60,61], pH value [62], reaction time [63,64], etc. ), additives amount [65], drying ways [66][67][68], post-treatment modification [69,70], etc.…”

Theoretical Study of the Impact of Pore Size in TiO₂ Aerogels on Photocatalytic Formaldehyde Decomposition

“…Among these common strategies, the sol-gel method has received the most widely studied. The pore size and specific surface area of TiO2 aerogels prepared by sol-gel method are affected by many factors, such as the concentration of precursor solution [58,59], preparation conditions (including temperature [60,61], pH value [62], reaction time [63,64], etc. ), additives amount [65], drying ways [66][67][68], post-treatment modification [69,70], etc.…”