Hierarchical Silica Research Articles

Biocatalytic Elimination of Pharmaceutics Found in Water With Hierarchical Silica Monoliths in Continuous Flow

Pharmaceutical products (PPs) are considered as emerging micropollutans in wastewaters, river and seawaters, and sediments. The biodegradation of PPs, such as ciprofloxacin, amoxicillin, sulfamethoxazole, and tetracycline by enzymes in aqueous solution was investigated. Laccase from Trametes versicolor was immobilized on silica monoliths with hierarchical meso-/macropores. Different methods of enzyme immobilization were experienced. The most efficient process was the enzyme covalent bonding through glutaraldehyde coupling on amino-grafted silica monoliths. Silica monoliths with different macropore and mesopore diameters were studied. The best support was the monolith featuring the largest macropore diameter (20 µm) leading to the highest permeability and the lowest pressure drop and the largest mesopore diameter (20 nm) ensuring high enzyme accessibility. The optimized enzymatic reactor (150 mg) was used for the degradation of a PP mixture (20 ppm each in 30 ml) in a continuous recycling configuration at a flow rate of 1 ml/min. The PP elimination efficiency after 24 h was as high as 100% for amoxicillin, 60% for sulfamethoxazole, 55% for tetracycline, and 30% for ciprofloxacin.

Efficient Removal of Hg(II) from Water under Mildly Acidic Conditions with Hierarchical SiO2 Monoliths Functionalized with -SH Groups.

In this work, novel adsorbents based on 3D hierarchical silica monoliths functionalized with thiol groups were used for the removal of Hg(II) ions from an acidic aqueous solution (pH 3.5). Silica monoliths were synthesized by using two different pluronic triblock polymers (P123 and F127) to study the effect of porous structure on their sorption capacity. Before and after functionalization by grafting with 3-mercaptopropyltrimethoxysilane (MPTMS), the monoliths were characterized by several techniques, and their Hg(II) removal potential was evaluated in batch experiments at 28 °C and pH 3.5, using different initial concentrations of Hg(II) ions in water (200–500 mg L−1). The thiol groups of the monoliths calcined at 550 °C showed thermal stability up to 300 °C (from TG/DTG). The functionalized monolith synthesized with P123 polymer and polyethylene glycol showed favorable hierarchical macro-mesopores for Hg(II) adsorption. M(P123)–SH exhibited 97% removal of Hg(II) at concentration 200 mg L−1. Its maximum adsorption capacity (12.2 mmol g−1) was two times higher than that of M(F127)–SH, demonstrating that the 3D hierarchical macro-mesoporosity allowing accessibility of Hg(II) to thiol groups favors the physical and chemical adsorption of Hg(II) under slightly acidic conditions.

Design of Hierarchical Self-Assembly 2d Silica and Their Derivative Catalysts with Accessible Open Transport Channels for Boosting Oxidative-Adsorptive Desulfurization in Fuel Oil

Design of Hierarchical Self-Assembly 2d Silica and Their Derivative Catalysts with Accessible Open Transport Channels for Boosting Oxidative-Adsorptive Desulfurization in Fuel Oil

Mass Transfer in Hierarchical Silica Monoliths Loaded With Pt in the Continuous-Flow Liquid-Phase Hydrogenation of p-Nitrophenol

Sol-gel-based silica monoliths with hierarchical mesopores/macropores are promising catalyst support and flow reactors. Here, we report the successful preparation of cylindrically shaped Pt-loaded silica monoliths (length: 2 cm, diameter: 0.5 cm) with a variable mean macropore width of 1, 6, 10, or 27 μm at a fixed mean mesopore width of 17 nm. The Pt-loaded monolithic catalysts were housed in a robust cladding made of borosilicate glass for use as a flow reactor. The monolithic reactors exhibit a permeability as high as 2 μm2 with a pressure drop below 9 bars over a flow rate range of 2–20 cm3 min−1 (solvent: water). The aqueous-phase hydrogenation of p-nitrophenol to p-aminophenol with NaBH4 as a reducing agent was used as a test reaction to study the influence of mass transfer on catalytic activity in continuous flow. No influence of flow rate on conversion at a fixed contact time of 2.6 s was observed for monolithic catalysts with mean macropore widths of 1, 10, or 27 µm. As opposed to earlier studies conducted at much lower flow velocities, this strongly indicates the absence of external mass-transfer limitations or stagnant layer formation in the macropores of the monolithic catalysts.

Design of Lubricant-Infused Surfaces Based on Mussel-Inspired Nanosilica Coatings: Solving Adhesion by Pre-Adhesion.

Slippery liquid-infused porous surfaces (SLIPSs) have attracted wide interest with regard to their excellent liquid repellency properties and broad applications in various fields associated with anti-adhesion. However, the preparation processes depending on the chemical properties of the substrate and the poor stability of the lubricant layer hinder the practical applications. In this work, a facile method to fabricate SLIPSs based on the mussel-inspired polydopamine (PDA)-mediated nanosilica structures is demonstrated. A variety of substrates can be decorated with SLIPSs by successive treatment of PDA-assisted sol-gel process, fluorination, and lubricant filling. The robust uniform and nanotextured silica coating, mediated by the pre-adhered PDA layer, shows enhanced lubricant-locking ability even when subjected to increased evaporation and high shear from flowing water or spinning compared with hierarchical silica rough structures. The obtained SLIPSs exhibit high transparency and excellent resistance against adhesion of liquid/solid contaminants and biofoulings through this pre-adhesion of PDA strategy. The well-defined nanosilica coating of high decoration covering micron-scaled pore walls enables improved durability of the slippery surfaces for antifouling of the porous membrane under pressure-driven filtration and this may be employed as a potential candidate for fouling resistance of porous materials.

CO2 capture (including direct air capture) and natural gas desulfurization of amine-grafted hierarchical bimodal silica

Amine grafting under hydrous conditions is emerging as a promising solution to developing amine grafted adsorbents with high amine loading and superior capture performance. In this study, a hierarchical bimodal mesoporous silica (HBS) that can be easily and cost-effectively synthesized was identified. Subsequently, HBS was amine grafted in anhydrous and hydrous conditions. The resulting material and its adsorptive performance were investigated. Hierarchical bimodal silica supports allow aminosilanes to more easily access the deep channels of the pores resulting in greater amine dispersion than SBA-15 type supports. The CO2 adsorption capacity of amine grafted hierarchical bimodal silica adsorbents and SBA-15 type adsorbents were measured at 25, 75, 90, 100 °C. The CO2 adsorption capacity and amine efficiency (reached 0.41 mol CO2/mol N) were significantly higher than that of SBA-15 type adsorbents. This is because HBS possesses two series of mesopores as opposed to one which promotes the diffusion of CO2 and allows for greater amine dispersion and consequently greater amine utilization. Wet grafted HBS displayed excellent cyclic stability after approximately 10 adsorption-desorption cycles. Under dry conditions and using ambient air containing 415 ppm of CO2 at 25 °C, the fixed bed breakthrough capacity of WG-HBS-0.6 was 1.04 mmol/g. To the best of our knowledge, the CO2 adsorption capacity and the direct air capture capacity exceed reported literature values for amine-grafted silica adsorbents. At similar amine loadings the H2S adsorption capacity of wet grafted hierarchical bimodal silica was similar to SBA-15 type adsorbents suggesting thermodynamics as opposed to pore structure plays a greater role during the H2S adsorption process. From the obtained results, hierarchical bimodal silicas are promising adsorbents for the capture of CO2 from ambient air and industrial gas streams and are also suitable for the removal of H2S.

Flexible Daytime Radiative Cooling Enhanced by Enabling Three-Phase Composites with Scattering Interfaces between Silica Microspheres and Hierarchical Porous Coatings.

Daytime radiative cooling has attracted considerable attention recently due to its tremendous potential for passively exploiting the coldness of the universe as clean and renewable energy. Many advanced materials with novel photonic micro/nanostructures have already been developed to enable highly efficient daytime radiative coolers, among which the flexible hierarchical porous coatings (HPCs) are a more distinguished category. However, it is still hard to precisely control the size distribution of the randomized pores within the HPCs, usually resulting in a deficient solar reflection at the near-infrared optical regime under diverse fabrication conditions of the coatings. We report here a three-phase (i.e., air pore-phase, microsphere-phase, and polymer-phase) self-assembled hybrid porous composite coating, which dramatically increases the average solar reflectance and yields remarkable temperature drops of ∼10 and ∼ 30 °C compared to the ambient circumstance and black paint, respectively, according to the rooftop measurements. Mie theory and Monte Carlo simulations reveal the origin of the low reflectivity of as-prepared two-phase porous HPCs, and the optical cooling improvement of the three-phase porous composite coatings is attributed to the newly generated interfaces possessing the high scattering efficiency between the hierarchical pores and silica microspheres hybridized with appropriate mass fractions. As a result, the hybrid porous composite approach enhances the whole performance of the coatings, which provides a promising alternative to the flexible daytime radiative cooler.

Hierarchical Silica Inverse Opals as a Catalyst Support for Asymmetric Molecular Heterogeneous Catalysis with Chiral Rh‐diene Complexes

AbstractThe efficacy of heterogeneous catalysis relies heavily on diffusion and distribution of reactants within catalyst supports. However, the presence of confinement, essential for reaction selectivity, drastically slows down molecular transport. Here, macro‐mesoporous silica inverse opal (SiO2−IO) films were used as a model system to study the rather unexplored molecular infiltration behavior using a probe molecule resembling a catalyst via confocal laser scanning microscopy (CLSM). CLSM analysis revealed homogeneous tracer distribution in SiO2−IO and attachment to both transport and mesopores. Bulk macro‐mesoporous SiO2−IO support was used for the attachment of mono‐ and bis‐functionalized chiral Rh‐diene complexes, and the catalytic activity and selectivity with respect to the support was studied. Lower enantioselectivity was observed with the bis‐functionalized ligand due to ligand entanglement and reduced accessibility of the active site, while the mono‐functionalized ligand gave an excellent enantioselectivity of 94 %ee in the asymmetric 1,2‐addition of triphenylboroxine to N‐tosylimines and could be recycled up to three times.

Preparation and evaluation of highly dispersed HHSS supported Cu-Fe bimetallic catalysts for higher alcohols synthesis from syngas

Porous carriers play an important role in the catalytic transformation of syngas into higher alcohols, which promises higher sustainability in C1 chemistry. In this work, a series of hierarchical hollow silica spheres (HHSS) supported Cu-Fe bimetal catalysts were successfully prepared through ultrasonic-assisted impregnation for higher alcohols synthesis from syngas. Structural characterization results indicate that the hierarchical hollow structure of HHSS support can be maintained and the Cu-Fe bimetallic nanoparticles are highly dispersed on HHSS surface. The catalytic performances of samples in the test of CO hydrogenation for higher alcohols synthesis were investigated. The results revealed that the conversion rate of CO and the selectivity of C2+OH alcohol increased first and then decreased with the decrease of the amount of Cu content in the CuxFey@HHSS catalyst. The highest CO conversion, alcohol selectivity and STYROH over Cu-Fe@HHSS catalyst are 65.1 %, 46.6 %, and 118.1 gkg−1 h−1, respectively. It was found that a large number of CuFe2O4 were formed in Cu-Fe@HHSS catalyst and also confirmed that the CuFe2O4 spinel and CuO-CuFe2O4 were converted to Cu-Fe5C2 composite in the spent Cu-Fe@HHSS catalyst, which can enhance the synergy between Cu-Fe bimetals. Furthermore, copper and iron are highly dispersed on HHSS after the reaction, which enhances the structural stability of the catalyst. Based on the development and utilization of low-cost catalysts and the production of clean liquid fuels, HHSS has a great prospect of catalyst support in the energy field.

Oxidative desulfurization of model oil and oil cuts with MoO3/SBA-15: experimental design and optimization by Box–Behnken method

Using wet impregnation method, MoO3 particles were loaded on hierarchical silica support, SBA-15, and applied for oxidative desulfurization (ODS) process from a model oil containing dibenzothiophene (DBT). The experiments were carried out by the use of H2O2 and acetonitrile as oxidant and extractant. The MoO3/SBA-15 catalyst was characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscope (FE-SEM) and Brunauer–Emmett–Teller (BET) analyses. At first, the effect of molybdenum loading was examined. Then, the effect of operating parameters on ODS including temperature, catalyst dosage, the molar ratio of H2O2/DBT and reaction time were investigated using Box–Behnken experimental design. The complete efficiency, ~ 100% S removal, was achieved by 0.004 g mL−1 catalyst at 55 oC within 49 min reaction time and H2O2/DBT = 9. At the optimized operating conditions, real oil cuts of gasoline and gas oil were tested and the S removal efficiency of 69.73% and 49% was achieved. The desulfurization activity of the catalyst from DBT model oil after 5 times regeneration was above 93%.

Metal Nanoparticles Confined within an Inorganic-Organic Framework Enable Superior Substrate-Selective Catalysis.

The search for catalysts with a perfect substrate selectivity toward the hydrogenation of nitroarenes is a goal of high importance, which still remains a significant challenge. Here, we designed a new type of catalyst with superior substrate selectivity by combining a space-confined effect and a hydrogen-bonding network, in which metal nanoparticles (MNPs) were confined in hierarchical hollow silica (HHS) with a poly(N-isopropylacrylamide) (PNIPA) coating. Given the strong induced properties of hydrogen-bond donors and acceptors in the HHS support and PNIPA coating, the as-synthesized catalyst would achieve perfect substrate selectivity for the hydrogenation of various nitroarenes and their mixture by thoroughly impeding the reduction of nitroarenes with any hydroxyl or carboxyl groups, which is typically very difficult to be realized over almost all of the reported supported-metal catalysts. Notably, the hydrogenation of nitroarenes can produce almost quantitative yields of anilines over the as-synthesized catalyst. Furthermore, density functional theory and experimental evidence are also provided for the hierarchical structure of HHS and PNIPA coating associated with substrates to demonstrate how a substrate could have access or be blocked into the confined active centers (MNPs). Therefore, this work would open a new window to design efficient catalysts for a wide variety of substrate-selective catalyses.

Micro solid phase extraction of cadmium and lead on a new ion-imprinted hierarchical mesoporous polymer via dual-template method in river water and fish muscles: Optimization by experimental design

In the present study, a new class of hierarchical silica based imprinted mesoporous polymers was fabricated by ion imprinting technology and it was applied to simultaneous selective extraction of cadmium and lead ions by micro solid phase extraction (μ-SPE). The biological nanocrystalline cellulose (BNCC) was prepared via acid catalyzed hydrolysis of cotton wool. The hierarchical silica (HS), as a substrate material, was synthesized via dual-template method, using BNCC and cetyltrimethylammonium bromide (CTAB) as hard and soft templates respectively. The structure and functional groups was characterized by Fourier infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and nitrogen adsorption-desorption. The results indicate that the as-prepared material has a hierarchical mesoporous structure with high specific surface area and high adsorption capacity for Cd(II) and Pb(II). The optimum experimental conditions in the proposed procedure were determined by response surface methodology (RSM) based on Box Behnken Design (BBD) and then it was successfully applied to determine Cd(II) and Pb(II) ions in the river water and fish samples.

In situ synthesis and characterization of sulfonic acid functionalized hierarchical silica monoliths

Surface functionalization of porous materials with sulfonic acid (SO3H) groups is of particular interest in applications involving ion exchange, acidic catalysis and proton conduction. Macro-mesoporous silica monoliths are ideal support structures for these applications, as they combine advection-dominated mass transport in the macropores with short diffusion lengths and a large surface area (available for functionalization) in their mesoporous skeleton. Here, we report on SO3H functionalized sol–gel silica monoliths with bimodal pore systems exhibiting macro- and mesoporosity, prepared according to a simple, efficient in situ synthesis protocol. Based on the co-condensation approach, thiol groups were introduced homogeneously into the pore structure, followed by their oxidation to SO3H groups and the simultaneous removal of the template. The macropore size, specific surface area, and coverage with SO3H groups are easily adjusted in this synthesis route. Importantly, the hybrid monoliths have a substantially narrower mesopore size distribution (relative standard deviation ~25%) than conventional sol–gel materials (>40%) and can be engineered crack-free in a robust column design (suitable for high-pressure flow-through operation) with mean mesopore size down to ~7 nm. They are characterized by IR spectroscopy, thermogravimetry, and elemental analysis as well as 13C and 29Si solid state NMR to corroborate the simple, efficient combination of sol–gel-based material synthesis, surface functionalization, and template removal (i.e., polymer extraction). Complementary, inverse gas chromatography is presented as a new approach to characterize the incorporated SO3H groups via surface energy analysis and particularly resolve changes in the Lewis acid–base characteristics engendered by that functionalization.

Highly Hierarchical Fibrillar Biogenic Silica with Mesoporous Structure Derived from the Perennial Plant Equisetum Fluviatile.

A new discovery of highly hierarchical fibrillar biogenic silica with mesoporous structure derived from the perennial plant Equisetum fluviatile was made. By removing the organic compounds through chemical and heat treatment, the biogenic silica skeleton can largely retained the original highly hierarchical structure of the plant stems. Infrared spectra, X-ray diffraction, and small-angle X-ray scattering, as well as nitrogen sorption analysis, were employed to characterize the crystalline phases, nanostructure, and porosity of the resulting material. Scanning electron microscopy and transmission electron microscopy investigation reveal that the biogenic silica are fibers with diameters of about 120-150 μm and lengths of more than a few centimeters. These fibers consist of smaller fasciculus with diameters of about 5-15 μm that are composed of three levels of particles with mass and surface fractal characteristics: primary particles on the order of 3-5 nm, secondary particles on the order of 9-12 nm, and tertiary particles on the order of 90-120 nm in size. It is also shown that the biogenic silica have mesoporous structure with an average pore size of 4-6 nm and a specific surface of 100-300 m2/g. Heat treatment at high temperature and residual K+ significantly affects the characteristics of the mesoporous structure of the biogenic silica, although it has little effect on the surface fractal structure of the secondary particles.

Hierarchically Organized and Anisotropic Porous Carbon Monoliths.

Anisotropy is a key factor regarding mechanical or transport properties and thus the functionality of porous materials. However, the ability to deliberately design the pore structure of hierarchically organized porous networks toward anisotropic features is limited. Here, we report two straightforward routes toward hierarchically structured porous carbon monoliths with an anisotropic alignment of the microstructure on the level of macro- and mesopores. One approach is based on nanocasting (NC) of carbon precursors into hierarchical and anisotropic silica hard templates. The second route, a direct synthesis approach based on soft templating (ST), makes use of the flexibility of hierarchically structured resorcinol–formaldehyde gels, which are compressed and simultaneously carbonized in the deformed state. We present structural data of both types of carbon monoliths obtained by electron microscopy, nitrogen adsorption analysis, and SAXS measurements. In addition, we demonstrate how the degree of anisotropy can easily be controlled via the ST route.

Hierarchical silica monolith prepared using cellulose monolith as template

Silica monoliths with a continuous porous structure have received much attention in biomedical and environmental applications owing to their high-performance separation/adsorption behaviors. However, it is difficult to maintain a porous structure in silica monoliths because their synthesis often involves complicated phase separation in sol-gel reactions. Herein, for the first time, we used an ecofriendly cellulose material as a template to prepare a hydrophilic and hierarchically porous silica monolith. The cellulose monolith template was prepared from cellulose acetate by a thermally induced phase separation method. The silica was then prepared in the presence of the cellulose monolith by a typical sol-gel reaction of tetraethyl orthosilicate (TEOS) to form the composite monolith, which was converted to the silica monolith by burning in air to remove the cellulose monolith. Owing to the hierarchically porous structure of the cellulose monolith template, the obtained silica monolith showed a similar hierarchically porous structure, as confirmed by scanning electron microscopy and nitrogen adsorption-desorption analyses. The pore structure could be controlled by changing the fabrication parameters, such as the kind of cellulose monolith and TEOS concentration. The surface-modified silica monolith was developed for further applications.

Robust and repairable bulk polymeric coatings with continuous superhydrophobicity for design control and underwater display

Functionalized polymeric materials with superhydrophobicity are considered as promising candidates for advanced and smart materials. Herein, a bulk superhydrophobic polymeric coating (BSPC) integrating robustness with repairability for design control and underwater display was fabricated based on the combination of covalently cross-linking epoxy acrylate resin (EAR) and hierarchical precipitated silica particle (PSP). By optimizing the ratio of polymer/particle (10: 4), the BSPC exhibited solid mechanical strength while facing various aggressive stress (>200 cycles). Thanks to the continuous superhydrophobicity constructed by hierarchical topography in the polymer skeleton, the BSPC was demonstrated enticing repairable behavior by polish (>40 cycles). More importantly, the regenerative rough structures enabled the BSPC to achieved design control sequentially via the shedding of the surface layer. Simultaneously, based on the underwater light-reflection, the underwater display was successfully realized on the designed BSPC, which may broaden the application fields of superhydrophobic materials. Additionally, the BSPC presented self-cleaning, anti-corrosion (pH in 1/14), anti-boiling (100 °C) and anti-freezing (0 °C) performances. Our findings conceivably propose a feasible strategy to fabricate versatile superhydrophobic polymeric materials with continuous, repairable and designable features for advanced and smart fields.

Co-Mn oxides supported on hierarchical macro-mesoporous silica for CO and VOCs oxidation

The hierarchical macro-mesoporous silica (MMS) was used for a first time as a support for catalysts for oxidation reactions. The macro-mesoporous silica was synthesized by the emulsions templating mechanism and modified separately or simultaneously using cobalt and manganese oxides. The obtained materials were characterized by different physicochemical methods and tested in the oxidation of CO and n-hexane combustion reactions. The modification of the MMS materials does not change significantly the mesopores characteristics; however, its pores are partially blocked by the oxides. For Co-MM sample agglomerates consisting of Co3O4 with average size of 100−150 nm and small spherical aggregates, encapsulated in the mesopores are formed. The amorphous manganese oxide preferentially fills up the mesopores in Mn-MM sample. Mixed oxide Co-Mn phases situated in the mesoporous network are formed in the bi-component Co-Mn samples. No significant change is observed either in the texture, or in the structural features of the catalysts after reaction.The highest catalytic activity for Co-MM sample in CO and n-hexane oxidation is related to the predomination of Co3+ species on the surface of Co3O4 and the more accessible oxide particles located outside the mesopores. The encapsulation of mixed Co-Mn oxides particles in the pores of the macro-mesoporous silica is responsible for a lower catalytic activity in comparison with that of the mono-component cobalt sample.

Amine modified nano-sized hierarchical hollow system for highly effective and stable oxidative-adsorptive desulfurization

Oxidative-adsorptive desulfurization (OADS) has become a frontier scientific topic. The main factors affecting the oxidation and adsorption performance are the polarity and size of porous catalysts. Herein, highly active and stable phosphotungstic acid immobilized on amino grafted nano-sized hierarchical hollow silica spheres (HPW-NH2-HHSS) was successfully prepared and completely characterized. The hierarchical hollow structure of HHSS support can be maintained after being functionalized with amine groups, and the active species of phosphotungstic acid H3PW12O40 (HPW) were well dispersed on the amine-modified HHSS and retained its Keggin structure of the heteropolyanions. The prepared catalyst was applied to simultaneous oxidation and adsorption of dibenzothiophene (DBT) from model fuel. The effects of contact time, the loading content of HPW, the dosage of catalyst, the [O]/[S] mole ratio, initial DBT concentration, and temperature on the removal efficiency of the OADS system were investigated. 20% HPW-NH2-HHSS demonstrated a high catalytic performance and its desulfurization efficiency could be reached to 99.36% in 30 min at a lower O/S rate (2.5). Meanwhile, the equilibrium adsorption capacity of dibenzothiophene sulfone (DBTO2) of this catalyst is about 374 mg g−1. Beside this there was no significant decline in catalyst performance after seven catalytic cycles, assigned to the chemical force between the positive charges of NH2 and the negative charges of HPW. It is the first time that this work involving the nano-sized hierarchical hollow system has been used for high-efficiency desulfurization and the theory has been advanced that the polar groups of catalysts replace polar solvents to adsorb S-oxidation products.

Hierarchical Cellular Structured Ceramic Nanofibrous Aerogels with Temperature-Invariant Superelasticity for Thermal Insulation.

Silica aerogels are attractive for thermal insulation due to their low thermal conductivity and good heat resistance performance. However, the fabrication of silica aerogels with temperature-invariant superelasticity and ultralow thermal conductivity has remained extremely challenging. Herein, we designed and synthesized a hierarchical cellular structured silica nanofibrous aerogel by using electrospun SiO2 nanofibers (SNFs) and SiO2 nanoparticle aerogels (SNAs) as the matrix and SiO2 sol as the high-temperature nanoglue. This pathway leads to the intrinsically random deposited SNFs assembling into a fibrous cellular structure, and the SNAs are evenly distributed on the fibrous cell wall. The unique hierarchical cellular structure of the ceramic nanofibrous aerogels endows it with integrated performances of the ultralow density of ∼0.2 mg cm-3, negative Poisson's ratio, ultralow thermal conductivity (23.27 mW m-1 K-1), temperature-invariant superelasticity from -196 to 1100 °C, and editable shapes on a large scale. These favorable multifeatures present the aerogels ideal for thermal insulation in industrial, aerospace, and even extreme environmental conditions.