Aerogel Network Research Articles

Biomimetic and flexible 3D carbon nanofiber networks with fire-resistant and high oil-sorption capabilities

A facile and scalable approach to prepare multilayered graphene coated carbon nanofiber (G-CNF) foam has been demonstrated for oil/chemical solvent spill clean-up applications. 2D electrospun polyacrylonitrile/itaconic acid (PANIA) membrane was converted into a nature inspired three-dimensional (3D) aerogel networks self-assembled by a gas foaming method. The 3D nanofiber foams were then coated with Graphene Oxide (GO) and carbonised into G-CNF foam. These foams display highly interconnected network; mimicking the features of chicken feather and demonstrated the synergistic properties of graphene and carbon nanofibers. These 3D foams were light weight, resilient and exhibited fire-resistance properties. The design features of the G-CNF foams comprise of interconnected carbon nanofiber layers leading to high specific surface area that contributed towards oil and solvents sorption properties. The G-CNF foams perform high saturation sorption capacity (86–153 g g−1) toward a range of oils and organic solvents and demonstrated sustained sorption capabilities even after 11 cycles. In addition, the topology of the G-CNF surface and the morphology of the nanofiber foam were simulated and further studied using microstructure computational modelling and numerical analysis, which altogether showed that a significant enhancement in the surface area-to-volume ratio resulting from the coated graphene on the G-CNF foam.

Perspectives in the modeling of biopolymer aerogel networks subject to wetting

AbstractAlginate‐based aerogels were shown to be non‐cytotoxic and to feature good cell adhesion, thus drawing their attention towards tissue engineering and regenerative medicine [1]. To this end, their mechanical properties under dry as well as wet conditions were subsequently investigated [2]. Upon wetting, these aerogels showed strong stiffening in their mechanical behavior. In this work, a micromechanically motivated model approach to describe this phenomenon is proposed. The nanofibers in the aerogel network are considered to undergo structural rearrangement upon being subjected to water. Furthermore, the collapse of the micropores (pore diameter below 5 nm) results in the formation of local hydrogel‐like network phase. The constitutive model is based upon the assumption that the total network can be decomposed into a hydrogel‐like network and a restructured aerogel network. The aerogel network is described based on the micromechanical model proposed by Rege et al. [3], while the hydrogel‐like network is modeled based on the phenomenological approach of Gent [4]. This first approach towards modeling shows reliable results against the experimental stress‐strain curves of alginate‐starch aerogels [5].

Physics-informed constitutive modelling of hydrated biopolymer aerogel networks.

Hydration induces significant structural rearrangements in biopolymer aerogels, resulting in a completely different mechanical behaviour compared to the one in the dry state. A network decomposition concept was earlier introduced to account for these changes, wherein the material network was decomposed into an open-porous aerogel one and a hydrogel-like one. Recent experimental evidences have supported this idea of the formation of a hydrogel-like network. Using these observations as a basis, in this paper, we present a micromechanical model describing the effect of hydration on the structural and mechanical properties of aerogels. The aerogel network is modelled based on the mechanics of their pore-walls, while the hydrogel-like network is modelled based on the statistical mechanics of their polymer chains by means of the Arruda-Boyce eight-chain model. The influence of diverse structural and material parameters on the mechanical behaviour is investigated. The effect of different degrees of wetting, from a pure aerogel to a pure hydrogel-like state, is captured by the model. The results are shown to be in good agreement with available experimental data.

Ice segregation induced self-assembly of salecan and grapheme oxide nanosheets into ion-imprinted aerogel with superior selectivity for cadmium (II) capture

Water pollution by highly toxic cadmium ion (Cd2+) poses a great threat to the human health and the ecosystem security. Thus, it is of great urgency and prime importance to develop green and effective strategies to remove Cd2+ from our environment. However, as a kind of potential heavy metal absorbent, graphene oxide (GO) materials are severely limited in practical applications due to the complicated collection procedure from effluent and bad selectivity toward certain metal ion. Here, we constructed a new aerogel by incorporating GO nanosheets into the salecan matrix through ice segregation induced self-assembly and ion-imprinting technologies. The hydrogen bond interactions between salecan and GO led to the complexation of aerogel network and were investigated systematically. The swelling ability, microstructure, and mechanical strength of the aerogel could be progressively modulated by simply changing the salecan content. Most strikingly, the Cd2+ adsorption onto the aerogels was dependent on the salecan content, pH, initial ion concentration, and contact time. The maximum adsorption capacity of the ion-imprinted aerogel was calculated to be 412.5 mg/g, notably higher than other Cd2+ adsorbents recently reported in literature. The adsorption kinetics and isothermal studies performed on Cd2+ matched the pseudo-second-order model and Langmuir model, implying the monolayer chemisorption mechanism. Simultaneously, the ion-imprinted aerogel showed an excellent selectivity for capturing Cd2+ and still maintained high adsorption capacity after five consecutive adsorption/desorption cycles. This work opened a door to construct an effective and eco-friendly aerogel system for thorough cleanup of Cd2+ in wastewater.

Ca-Zn-Ag Alginate Aerogels for Wound Healing Applications: Swelling Behavior in Simulated Human Body Fluids and Effect on Macrophages.

Chronic non-healing wounds represent a substantial economic burden to healthcare systems and cause a considerable reduction in quality of life for those affected. Approximately 0.5–2% of the population in developed countries are projected to experience a chronic wound in their lifetime, necessitating further developments in the area of wound care materials. The use of aerogels for wound healing applications has increased due to their high exudate absorbency and ability to incorporate therapeutic substances, amongst them trace metals, to promote wound-healing. This study evaluates the swelling behavior of Ca-Zn-Ag-loaded alginate aerogels and their metal release upon incubation in human sweat or wound fluid substitutes. All aerogels show excellent liquid uptake from any of the formulas and high liquid holding capacities. Calcium is only marginally released into the swelling solvents, thus remaining as alginate bridging component aiding the absorption and fast transfer of liquids into the aerogel network. The zinc transfer quota is similar to those observed for common wound dressings in human and animal injury models. With respect to the immune regulatory function of zinc, cell culture studies show a high availability and anti-inflammatory activity of aerogel released Zn-species in RAW 264.7 macrophages. For silver, the balance between antibacterial effectiveness versus cytotoxicity remains a significant challenge for which the alginate aerogels need to be improved in the future. An increased knowledge of the transformations that alginate aerogels undergo in the course of the fabrication as well as during wound fluid exposure is necessary when aiming to create advanced, tissue-compatible aerogel products.

Assembly of Ultralight Dual Network Graphene Aerogel with Applications for Selective Oil Absorption.

High-performance graphene aerogels with well-developed internal structures are generally obtained by means of introducing additive materials such as carbon nanotubes, cellulose, and lignin into the aerogel network, which not only enhances the cost but also complicates the preparation process. Therefore, tailoring the internal structure of pristine graphene aerogel in a feasible way to achieve high performance is of great significance to the practical applications. Herein, a novel cysteamine/l-ascorbic acid graphene aerogel (CLGA) was fabricated by a simple one-step hydrothermal method followed by freeze-drying. Through the creative combination of the reducing agent l-ascorbic acid and cross-linking agent cysteamine, a dual-network structure was constructed by both layered physical stacking and vertical chemical cross-linking. The addition of cysteamine not only enhanced the reduction degree but also assisted the formation of more vertical connections between graphene nanosheets, resulting in more abundant pores with smaller sizes compared with graphene aerogels prepared by the traditional hydrothermal reduction method. CLGA possessed an ultra-low density of 4.2 mg/cm3 and a high specific surface area of 397.9 m2/g. As expected, this dual-network structure effectively improved the absorption capacity toward a variety of oil and organic solvents, with an outstanding oil absorption capacity up to 310 g/g. Furthermore, CLGA possessed good mechanical properties and oil/water selectivity. The absorbed oil could be recovered by both continuous absorption-removal process and mechanical squeezing, making the as-prepared aerogel superior absorbent material for a variety of applications, such as selective oil absorption and water treatment.

Enhanced thermal shrinkage behavior of phenolic-derived carbon aerogel-reinforced by HNTs with superior compressive strength performance

A novel carbon/m-HNTs composite aerogel was synthesized by introducing the modified halloysite nanotubes (m-HNTs) into phenolic (PR) aerogels through chemical grafting, followed with carbonization treatment. In order to explore the best proportion of HNTs to phenolic, the micromorphology of PR/m-HNTs were investigated by SEM before carbonization, confirming 10 wt% of m-HNTs is most beneficial to the porous network of aerogels. The interaction between PR and HNTs was studied by FTIR spectra, and microstructure evolution of the target product-carbon/m-HNTs composite aerogel were illustrated by SEM and TEM techniques. SEM patterns indicated that the carbon/m-HNTs aerogels maintain a stable porous structure at 1000 °C (carbonization temperature), while a ~20 nm carbon layer was formed around m-HNTs generating an integral unit through TEM analysis. Specific surface area and pore size distribution of composite aerogels were analyzed based on mercury intrusion porosimetry and N2 adsorption–desorption method, the obtained results stayed around 500 m2g−1 and 1.00 cm3g−1 (pore volume) without significant discrepancy, compared with pure aerogel, showing the uniformity of pore size. The weight loss rate (26.76%) decreased greatly compared with pure aerogel, at the same time, the best volumetric shrinkage rate was only 30.83%, contributed by the existence of HNTs supporting the neighbor structure to avoid over-shrinking. The highest compressive strength reached to 4.43 MPa, while the data of pure aerogel was only 1.52 MPa, demonstrating the excellent mechanical property of carbon/m-HNTs aerogels.

Flexible, Strong, Multifunctional Graphene Oxide/Silica-Based Composite Aerogels via a Double-Cross-Linked Network Approach.

Multifunctional silica-based aerogels are an emerging material due to their unique properties and wide applications. However, their large-scale production and application are limited due to the high cost and cumbersome preparation process. Herein, we prepare graphene oxide (GO)/silica-based composite aerogels via a simple in situ sol-gel reaction. GO nanosheets (GOs) are functionalized with polyethylenimine (PEI) and 3-glycidyloxypropyltrimethoxysilane (GPTMS) successively. After a cohydrolysis and condensation of trimethoxymethylsilane (MTMS) and dimethoxydimethylsilane (DMDMS) in the presence of GOs and a convenient ambient-pressure drying process, the composite aerogels are obtained. In addition to the normal cross-linking of MTMS and DMDMS, the GOs also behave as cross-linking points to significantly enhance the mechanical properties and thermal stability of the network of the composite aerogels. The pore structure of the aerogels is tailored by varying the GO loads as well as its surface modification. The Young's modulus of a composite aerogel with a GO load of 0.5 wt % is about 5 times that for a neat polysiloxane aerogel, and the maximum degradation rate temperature is increased to over 90 °C. Compared with pure polysiloxane aerogel, the thermal insulation and flame resistance are also improved by a small addition of GOs. Moreover, GO/silica-based composite aerogels show stable piezo-resistive behavior. With the excellent mechanical properties, thermal stability, and multifunctionality, GO/silica-based composite aerogels show promising applications under some harsh and extreme conditions.

Stable thermal transport in reduced graphene-oxide aerogel at elevated temperatures

We investigate thermal transport in three-dimensional graphene aerogel networks at elevated temperatures. The aerogels are solution-processed from graphene-oxide flakes using amine-based linkers and then partially reduced to impart stability in the chemical structure at elevated temperatures. Thermal conductivity of the system is estimated using steady-state electrothermal technique in vacuum in the temperature interval from 30 to 200 °C. The thermal conductivity value is κ ∼ 0.2 W/mK at room temperature, and is found to be weakly dependent on temperature across the entire temperature interval. To examine the microscopic origin of this stable response, the thermal conductivity estimates are complemented with insights from temperature-dependent transient electrothermal response. We show that the temperature stable thermal insulation behaviour observed in this system can be attributed to two factors: point-defect scattering at the flake level from the remnant oxygen-functionalities which dominates over Umklapp scattering processes, and another contribution that arises from interfacial thermal resistance between flakes. The partial reduction thus achieves a delicate balance between imparting chemical stability while also retaining the dominance of point-defect phonon scattering, where the latter contributes to temperature stable thermal conductivity.

Macroscopic behavior of the distorted A and B phases and the polar phase of superfluid He3 in an anisotropic aerogel

We describe the macroscopic behavior of superfluid $^{3}\mathrm{He}$ in the polar and the distorted $A$ and $B$ phases in an anisotropic aerogel. It turns out that the distorted $A$ phase shares many features with superfluid $^{3}\mathrm{He}\ensuremath{-}A$. Its order parameter contains the polar phase as well as the $A$ phase as a smooth limiting case. The former is in agreement with the fact that the phase transition polar to distorted $A$ is observed to be of second order. Due to the different structure of the order parameter, the unit vector $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{l}$, which is characteristic of the superfluid $^{3}\mathrm{He}\ensuremath{-}A$ and the distorted $A$ phase, is not present in the polar phase. As new macroscopic variables compared to superfluid $^{3}\mathrm{He}$ we have for the superfluid distorted $A$ phase in an aerogel the strain field associated with the aerogel network. In addition, we have in superfluid $^{3}\mathrm{He}$ relative rotations between the anisotropic gel network and the $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{l}$ vector as a macroscopic variable. As a result of these additional macroscopic variables we find new static and dynamic cross-coupling terms, which come as reversible (zero entropy production) as well as as irreversible contributions. The polar phase in an anisotropic aerogel is anisotropic in its elastic properties. We have as additional macroscopic variables relative rotations similar to those of a nematic liquid crystalline elastomer, since the preferred direction in the polar phase is even under time reversal and not odd as for the distorted $A$ phase. These additional features lead to static and dissipative cross-coupling terms, which cannot exist for a polar phase in an isotropic aerogel. For the distorted $B$ phase we find for the orbital part a macroscopic dynamic behavior which shares some features with that of the polar phase. In contrast to the polar phase, however, the distorted $B$ phase does not show relative rotations, since there is only one preferred direction. The preferred direction in the distorted $B$ phase leads to a preferred direction in spin space as well. As a consequence the spin waves become anisotropic and longitudinal and transverse spin waves become coupled, even in the absence of a magnetic field. We also discuss briefly the coupling to the spin degrees of freedom in the polar and the distorted $A$ phase.

Highly efficient thermo-electrochemical energy harvesting from graphene–carbon nanotube ‘hybrid’ aerogels

Three-dimensional scaffold assemblies consisting of thermally reduced graphene oxide nanosheets and small-diameter carbon nanotubes were synthesized as potential ‘all carbon’ thermo-electrochemical energy harvesters. The facile hydrothermal–solvothermal synthesis route in which organic wet chemistry used was to inter crosslink the well-dispersed graphene oxide nanosheets with carbon nanotubes followed by freeze-drying to produce monolithic aerogel networks with ultralow densities, tunable mesoscopic pore sizes, tailorable functionality and morphology. They exhibited high electrical conductivity due to multiplex topologies owing to the integration with carbon nanotubes, which has high density of states at van Hove singularities, accompanied by expected larger surface area and sufficient edge plane sites, which in-turn enhance surface adsorption and rapid ion transportation. We conducted thermoelectric and thermo-electrochemical power generation from these ‘hybrid’ aerogel materials and using two different designs of galvanic thermo-cells. Consequently, higher Seebeck (electronic; Se as well as ionic; Sion) coefficients and thermopower generation was measured that confirmed low thermal responsiveness attributed to smaller domain size generated by hierarchical mesoporosity and open network. These multiple features demonstrate significant potential of these novel electrodes in galvanic thermocells for low-grade thermal energy harvester with higher relative conversion efficiency.

Electrically Heatable Graphene Aerogels as Nanoparticle Supports in Adsorptive Desulfurization and High‐Pressure CO2 Capture

AbstractReduced‐graphene‐oxide (rGO) aerogels provide highly stabilising, multifunctional, porous supports for hydrotalcite‐derived nanoparticles, such as MgAl‐mixed‐metal‐oxides (MgAl‐MMO), in two commercially important sorption applications. Aerogel‐supported MgAl‐MMO nanoparticles show remarkable enhancements in adsorptive desulfurization performance compared to unsupported nanoparticle powders, including substantial increases in organosulfur uptake capacity (>100% increase), sorption kinetics (>30‐fold), and nanoparticle regeneration stability (>3 times). Enhancements in organosulfur capacity are also observed for aerogel‐supported NiAl‐ and CuAl‐metal‐nanoparticles. Importantly, the electrical conductivity of the rGO aerogel network adds completely new functionality by enabling accurate and stable nanoparticle temperature control via direct electrical heating of the graphitic support. Support‐mediated resistive heating allows for thermal nanoparticle recycling at much faster heating rates (>700 °C∙min−1) and substantially reduced energy consumption, compared to conventional, external heating. For the first time, the CO2 adsorption performance of MgAl‐MMO/rGO hybrid aerogels is assessed under elevated‐temperature and high‐CO2‐pressure conditions relevant for pre‐combustion carbon capture and hydrogen generation technologies. The total CO2 capacity of the aerogel‐supported MgAl‐MMO nanoparticles is more than double that of the unsupported nanoparticles and reaches 2.36 mmol·CO2 g−1 ads (at pCO2 = 8 bar, T = 300 °C), outperforming other high‐pressure CO2 adsorbents.

Gelation, flame retardancy, and physical properties of phosphorylated microcrystalline cellulose aerogels

Flame-retardant bio-based cellulose aerogels, with abundant renewable sources, are considered as promising sustainable heat-insulation alternatives to conventional petroleum-based foams. An environmentally friendly method was employed to fabricate phosphorylated microcrystalline cellulose (PMCC) aerogel through the gelation of PMCC/H2O dispersion and freeze-drying of PMCC hydrogel. The dispersion stability of PMCC and its readiness to undergo gelation in the aqueous phase were enhanced by increasing the phosphorous content via phosphorylation, thereby effectively weakening the strong intra- and intermolecular hydrogen-bond interactions of the cellulose chains. The morphology of the PMCC aerogel changed from a short rod-shaped and sheet-like aggregation of a three-dimensional skeleton structure to a mostly sheet-like aggregation of a three-dimensional structure with increased phosphate esterification. Remarkably, PMCC aerogels exhibited improved flame retardancy and superior suppression of toxic gas, compared to MCC. This is attributable to the synergic effect of phosphate dehydration, catalytic carbonization, and protection of the aerogel network structure.

Rh-Decorated Three-Dimensional Graphene Aerogel Networks as Highly-Efficient Electrocatalysts for Direct Methanol Fuel Cells

The exploration and development of highly-efficient Pt-alternative catalysts with acceptable costs are very essential for the large-scale commercial applications of direct methanol fuel cell (DMFC) technology. Herein, we demonstrate a facile and cost-effective self-assembly approach to the bottom-up fabrication of Rh-decorated three-dimensional graphene aerogel (Rh/3D-GA) networks as efficient DMFC anode catalysts. With the distinct textural features including large surface area, 3D porous structure, uniform Rh dispersion, and good electron conductivity, the resultant Rh/3D-GA hybrid architecture shows superior electrocatalytic properties toward methanol oxidation reaction, such as large electrochemically active surface area, low onset potential, high mass activity as well as excellent long-term stability, all of which are more competitive than those of Rh catalysts deposited on conventional carbon black, carbon nanotubes, and two-dimensional graphene supports.

High-performance mesoporous γ-Fe2O3 sphere/graphene aerogel composites towards enhanced lithium storage

Transition metal oxides have recently been demonstrated as highly attractive anodes for high-capacity lithium ion batteries, whose electrochemical properties could be further improved through rational architecture design and incorporating reliable conductive network. Herein, mesoporous γ-Fe2O3 spheres/graphene aerogel composites were synthesized via a solvothermal pathway followed by suitable annealing. Experimental results reveal the uniform mesoporous structure and well-dispersed γ-Fe2O3 spheres with the size of 300−400 nm embedded in the mesopores of the graphene aerogel network. Compared with α-Fe2O3/graphene aerogel and pure γ-Fe2O3, the as-synthesized composite delivers, at the first cycle, a high discharging capacity of 1080 mAh g−1 at current density of 200 mA g−1. Even at much higher current density of 8000 mA g−1, satisfactory discharging capacities of 421.5 mAh g−1 can still be achieved. Upon 100 charging-discharging cycles, the specific capacity of as high as 890.5 mAh g−1 at 200 mA g−1 is maintained. The enhanced electrochemical properties could be attributed to their favorable three-dimensional graphene aerogel network, which accounts for the improved structural stability and electronic conductivity of γ-Fe2O3 during the lithiation/delithiation process.

Emerging Dual‐Channel Transition‐Metal‐Oxide Quasiaerogels by Self‐Embedded Templating

AbstractThe lack of precise control of particle sizes is the critical challenge in the assembly of 3D interconnected transition‐metal oxide (TMO) for newly‐emerging energy conversion devices. A self‐embedded templating strategy for preparing the TMO@carbon quasiaerogels (TMO@C‐QAs) is proposed. By mimicking an aerogel structure at a microscale, the TMO@C‐QA successfully assembles size‐controllable TMO nanoparticles into 3D interconnected structure with surface‐enriched carbon species. The morphological evolutions of intermediates verify that the self‐embedded Ostwald ripening templating approach is responsible for the dual‐channel TMO@C‐QA formation. The general self‐embedded templating strategy is easily extended to prepare various TMO@C‐QAs, including the Co3O4@C‐QA, Mn3O4@C‐QA, Fe2O3@C‐QA, and NiO@C‐QA. Benefiting from the unparalleled 3D interconnected network of aerogels, the Co3O4@C‐QA displays superior bifunctional catalytic activities for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), as well as high specific capacity and excellent long‐term stability for lithium‐ion battery (LIB) anode. A proof‐of‐concept battery‐powered electrolyzer with Co3O4@C‐QA cathode and anode powered by a full LIB with Co3O4@C‐QA anode is presented. The battery‐powered electrolyzer made of the state‐of‐the‐art TMOs can exhibit great competitive advantages due to its supreme multifunctional energy conversion performance for future water electrolysis.

Ultra-light MXene aerogel/wood-derived porous carbon composites with wall-like “mortar/brick” structures for electromagnetic interference shielding

Renewable porous biochar and 2D MXene have attracted significant attention in high-end electromagnetic interference (EMI) shielding fields, due to unique orderly structures and excellent electrical conductivity (σ) value. In this work, the wood-derived porous carbon (WPC) skeleton from natural wood was performed as a template. And excellent conductive and ultra-light 3D MXene aerogel was then constructed to prepare the MXene aerogel/WPC composites, based on highly ordered honeycomb cells inner WPC as a microreactor. Higher carbonization temperature is more conducive to the graphitization degree of natural wood. MXene aerogel/WPC composites achieve the optimal EMI SE value of up to 71.3 dB at density as low as 0.197 g/cm3. Such wall-like “mortar-brick” structures (WPC skeleton as “mortar” and MXene aerogel as “brick”) not only effectively solve the unstable structure problem of MXene aerogel networks, but also greatly prolong the transmission paths of the electromagnetic waves and dissipate the incident electromagnetic waves in the form of heat and electric energy, thereby exhibiting the superior EMI shielding performance. In addition, MXene aerogel/WPC composites also exhibit good anisotropic compressive strength, excellent thermal insulation and flame retardant properties. Such ultra-light, green and efficient multi-functional bio-carbon-based composites have great application potential in the high-end EMI shielding fields of aerospace and national defence industry, etc.

A self-supported 3D aerogel network lithium–sulfur battery cathode: sulfur spheres wrapped with phosphorus doped graphene and bridged with carbon nanofibers

An integrated PGCNF/S aerogel with a “network” structure has effectively restricted the shuttling of polysulfides and exhibited promising lithium ion storage capability.

Stiffening of biopolymer aerogel networks upon wetting: A model-based study

The mechanism behind the stiffening effect observed in the stress-strain response of alginate-starch aerogels upon being exposed to wetting is investigated in this paper, via a physically motivated model approach. A network decomposition concept is introduced, whereby the highly nanoporous network is decomposed into a swollen aerogel network and a hydrogel-like network. The aerogel network is modeled by considering idealized square-shaped microcells of varying sizes. An attempt is made to explain the stiffening of the network, upon wetting, based on changes in the fibril characteristics of the aerogel network upon swelling and formation of a hydrogel-like phase in the microporous region. In this first approach, the aerogel network is described based on a micro-mechanical model, while the hydrogel-like network is described using a phenomenological one. The results of the proposed model idea are in very good agreement with the experimental data of alginate-starch aerogels under different degrees of wetting.

SiBCN ceramic aerogel/graphene composites prepared via sol-gel infiltration process and polymer-derived ceramics (PDCs) route

The SiBCN ceramic aerogel/graphene composites were synthesized by combining a simple sol-gel infiltration process with CO2 supercritical drying technology and polymer-derived ceramics route. In order to select the best preceramic sample for sintering, the micromorphology of PSNB aerogel/graphene composites fabricated with different graphene oxide solution concentrations were investigated. The microstructure evolution of the prepared SiBCN ceramic aerogel/graphene composites and phase composition were studied by SEM, TEM and XRD, the pore structure of the preceramic composites pyrolyzed at 1200 °C was tested by specific surface area and pore size analyzer. Furthermore, the compressive strain-stress curve and toughening mechanisms of composites were also investigated in detail. The results showed that all the preceramic composites and obtained ceramic aerogel composites possessed the mesoporous structure. The basic structure of SiBCN aerogel network changed from the initial spherical particles accumulation to the nanowires lapping with the sintering temperature increased from 800 °C to 1200 °C. After pyrolyzing at 1200 °C, the specific surface area and pore volume for the sample were 101.61 m2 g−1 and 1.43 cm3 g−1, respectively, and a small amount of β-SiC crystalline phases were formed in amorphous ceramic matrix and had an relatively uniform distribution. Moreover, the paepared ceramic aerogel composites possessed a certain degree of toughness, the toughening mechanisms of composite samples mainly included the crack deflection, graphene pull-out, graphene bridging and graphene crumpling.