Preparation and microstructure of CuO-CoO-MnO/SiO2 nanocomposite aerogels and xerogels as catalyst carriers

Zhao, Yueqing; Liang, Yeru; Xin, Zhao; Jia, Qianyi; Li, Hongsheng

doi:10.1016/s1002-0071(12)60065-3

Cited by 20 publications

(3 citation statements)

References 9 publications

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“…Aerogels are promising materials in a wide range of fields, including supercapacitor [ 1 , 2 ], electromagnetic wave absorption materials [ 3 ], oil-water separation materials [ 4 , 5 ], superabsorbent [ 6 , 7 , 8 ], catalyst support [ 9 , 10 ], and thermal insulation materials [ 11 , 12 , 13 ], because of their outstanding advantages including super high specific area, low density, high porosity, and low thermal conductivity [ 14 , 15 , 16 ]. So far, a variety of polymer-based aerogels, including poly(vinyl alcohol) [ 5 , 9 , 11 , 17 ], cellulose [ 11 , 18 , 19 , 20 , 21 , 22 ], alginate [ 23 ], chitosan [ 24 ], and pectin [ 25 ] have been developed. With the incorporation of polymer matrix, the inorganic/polymer composite aerogels exhibited lower pore size, higher density, lower thermal conductivity, and better mechanical properties, compared to those of inorganic aerogels [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Flame-Retardant and Enhanced PVA-Based Composite Aerogels through Interpenetrating Cross-Linking Networks

Deng

Wang

et al. 2023

Polymers

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Poly(vinyl alcohol) (P)/alginate (A)/MMT (M) (PAM) composite aerogels was modified through interpenetrating cross-linking of methyltriethoxysilane (Ms) or γ-aminopropyltriethoxysilane (K) and calcium ion (Ca2+) as a cross-linking agent, respectively. The compressive moduli of the cross-linked PAM/MsCa and PAM/KCa aerogels greatly increased to 17.4 and 22.1 MPa, approximately 10.5- and 8.2-fold of that of PAM aerogel, respectively. The limited oxygen index (LOI) values for PAM/MsCa and PAM/KCa composite aerogels increased from 27.0% of PAM aerogel to 40.5% and 56.8%. Compared with non-cross-linked PAM aerogel, the peak heat release rate (PHRR) of PAM/MsCa and PAM/KCa composite aerogels dramatically decreased by 34% and 74%, respectively, whereas the PAM/KCa aerogel presented better flame retardancy and lower smoke toxicity than the PAM/MsCa aerogel because of the release of more inert gases and the barrier action of more compact char layer during the combustion. The highly efficient flame-retardant PAM-based composite aerogels with excellent mechanical properties are promising as a sustainable alternative to traditional petroleum-based foams.

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Section: Introductionmentioning

confidence: 99%

Highly Efficient Flame-Retardant and Enhanced PVA-Based Composite Aerogels through Interpenetrating Cross-Linking Networks

Deng

Wang

et al. 2023

Polymers

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“…Silica aerogels have broad applications in numerous fields, such as thermal insulation [ 1 , 2 , 3 , 4 , 5 ], catalyst carriers [ 6 , 7 ], aerospace [ 8 , 9 ] and adsorption [ 10 , 11 , 12 , 13 ]. However, due to the nanoporous structure and high porosity, silica aerogels exhibit high brittleness and low integrity.…”

Section: Introductionmentioning

confidence: 99%

Heat-Treated Aramid Pulp/Silica Aerogel Composites with Improved Thermal Stability and Thermal Insulation

Li,

Shen,

et al. 2023

Gels

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In this work, we prepared heat-treated aramid pulp/silica aerogel composites (AP/aerogels) and investigated in detail the feasibility of improving thermal stability and thermal insulation via tailored heat treatment. The microstructure and FTIR spectra reveal that AP/aerogels are formed by a physical combination of the silica aerogel matrix and aramid pulps. When the heat treatment temperature increases, the density slightly decreases and then increases to the maximum due to the significant volume shrinkage. The pyrolysis of aramid pulp and the collapse of silica skeletons occur during heat treatment; nevertheless, the typical structures of AP/aerogels do not change significantly. It is also found that both the hydrophobicity and the thermal insulation decrease with the increasing heat treatment temperature. We note that when the heat treatment is at 600 °C, the AP/aerogel still maintains a low density of 0.19 g/cm3 and a contact angle of 138.5°. The thermal conductivity is as low as 26.11 mW/m/K, measured using the transient hot wire method. Furthermore, the heat-treated AP/aerogels can avoid heat shock and possible thermal hazards during practical thermal insulation applications. The onset temperatures of the thermal decomposition of AP/aerogels increase from 298.8 °C for an untreated one to 414.7 °C for one treated at 600 °C, indicating that the thermal stability of AP/aerogels is improved significantly. This work provides a practical engineering approach to expand the thermal insulation applications of silica aerogel composites.

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“…The common SAs are composed of over 95% pores and less than 5% silica skeletons (Hüsing and Schubert, 1998), which make them possess exceptional properties, such as an ultra-low density, incredibly low thermal conductivity, and a high specific surface area (Pisal and Rao, 2016;Pisal and Venkateswara Rao, 2017). The excellent properties render SAs ideally suited for a wide range of applications, such as thermal insulation (Baetens et al, 2011;Koebel et al, 2012;Cuce et al, 2014), catalyst supports (Pierre, 2010;Zhao et al, 2011), separation (Yu et al, 2015), liquid/gas adsorption (Woermeyer et al, 2012;Mahani et al, 2018;Wu et al, 2018), and aerospace applications (Randall et al, 2011;Bheekhun et al, 2013). As the fast and 10.3389/fmats.2023.1225481 cost-effective preparation technology (Koebel et al, 2016;Huber et al, 2017), the application scale and fields will continuously increase in the near future (Smirnova and Gurikov, 2018).…”

Section: Introductionmentioning

confidence: 99%

Effects of mechanical grinding on the physicochemical properties of silica aerogels

Li,

Zeng,

Shen

et al. 2023

Front. Mater.

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Mechanical grinding is a facile method to get silica aerogels (SAs) with various particle sizes. However, the relationship between the grinding parameters and physicochemical properties is still unclear. In this study, we concentrated on the effects of grinding time and grinding speed on the physical and chemical properties of silica aerogels. The results reveal that the physicochemical properties of silica aerogels are more sensitive to the grinding speed rather than the grinding time. When the grinding speed is over 200 rpm, large particles of silica aerogels are crushed into smaller particles with obviously decreasing particle sizes and the silica skeletons of silica aerogels have collapsed. The reduction of particle sizes and the collapse of skeleton lead to an increase in both the tap density and thermal conductivity. Therein, the thermal conductivity is positively proportional to the density. Furthermore, the grinded silica aerogels powders still possess the contact angles over 135°, indicating the good hydrophobicity. All these demonstrate that the mechanical grinding has evident effects on the microstructure, density, thermal conductivity and particle sizes, which further impact the performance of silica aerogels during the practical applications. Given the expanding applications of SAs across various industries, the study serves as a valuable reference for optimizing the mechanical post-treatment of SAs, facilitating the achievement of desired particle sizes. Ultimately, this research holds great potential in diversifying the application fields of SAs in their powdered form.

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Preparation and microstructure of CuO-CoO-MnO/SiO2 nanocomposite aerogels and xerogels as catalyst carriers

Cited by 20 publications

References 9 publications

Highly Efficient Flame-Retardant and Enhanced PVA-Based Composite Aerogels through Interpenetrating Cross-Linking Networks

Highly Efficient Flame-Retardant and Enhanced PVA-Based Composite Aerogels through Interpenetrating Cross-Linking Networks

Heat-Treated Aramid Pulp/Silica Aerogel Composites with Improved Thermal Stability and Thermal Insulation

Effects of mechanical grinding on the physicochemical properties of silica aerogels

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