Robust, Highly Thermally Stable, Core–Shell Nanostructured Metal Oxide Aerogels as High-Temperature Thermal Superinsulators, Adsorbents, and Catalysts

Abstract

Robust, highly thermally stable, MO x /(MO x − SiO 2 )/SiO 2 core−shell nanostructured metal oxide aerogels with a MO x core and (MO x −SiO 2 )/SiO 2 shell are produced via novel alkoxide chemical liquid deposition techniques. The core−shell nanostructure not only significantly reinforces the nanoparticles but also effectively inhibits the crystal growth and phase transition of metal oxide upon heat treatment, which enhances the heat resistance from approximate 400− 800°C up to 1000−1300°C. The resultant core−shell nanostructured Al 2 O 3 , ZrO 2 , and TiO 2 aerogels can support at least 5800 times their weight and exhibit high surface areas of 139, 186, and 154 m 2 /g after fired at 1300, 1000, and 1000°C, respectively, which are the highest surface areas for metal oxide aerogels ever reported. We demonstrate that the core−shell ZrO 2 and TiO 2 aerogels show enhanced adsorption and photocatalytic performances, respectively, for dye after fired at 1000°C. The core−shell Al 2 O 3 aerogel/mullite fiber/TiO 2 composite possesses ultralow thermal conductivities of 0.058, 0.080, and 0.11 W/mK at 800, 1000, and 1200°C, respectively, which are the lowest values for inorganic aerogels ever reported. The resulting materials are promising candidates as hightemperature (400−1300°C) thermal superinsulators, adsorbents, and catalysts.

Multi-layer and open three-dimensionally ordered macroporous TiO2–ZrO2 composite: diversified design and the comparison of multiple mode photocatalytic performance

“…This may be attributed to the different hydrolysis speeds of the Ti and Zr source precursors. The hydrolysis speed of Zr source is relatively slow [34], leading to a lower ZrO 2 content than expected. Additionally, the vacuum impregnation and the calcination methods could highly disperse ZrO 2 on the TiO 2 surface, making XRD detecting exceedingly difficult [12].…”

Antimicrobial Treatment of Different Metal Oxide Nanoparticles: A Critical Review

“…25 When Zr 4+ and Si 4+ are added to the titanium structure, it increases the anatase stability along with helping in rutile alteration (ART). [26][27] There are numerous approaches that bring about the formation of TiO 2 NPs. The most popular technique is the sol-gel proses.…”

Versatile Double-Cross-Linking Approach to Transparent, Machinable, Supercompressible, Highly Bendable Aerogel Thermal Superinsulators

“…The flexibility of PVPSQ, PAPSQ, PVPMS, and PAPMS aerogels and xerogels is significantly higher than that of traditional silica 9 and metal oxide aerogels. 40 In particular, the superflexibility of PVPMS and PAPMS aerogels/xerogels has not been observed in recently reported aerogels such as PMSQ, 15 PVSQ, 16 organo-bridged polysiloxanes, [18][19][20] nanocellulose, 22,23 chitosan, 24 polymer 3,27 and silica-based organic-inorganic hybrid aerogels. 11,13 In addition, the PVPMS aerogels exhibit the similar bending flexibility but much higher elasticity against compression compared to those of a commercial phenol foam with a sufficiently low thermal conductivity of ~ 20 mW m −1 K −1 ( Figure S10).…”