High-Yield Preparation and Properties of Phenolic Resin-Based Carbon Microspheres.

This study aims to enhance the production efficiency of carbon microspheres (CS) and expand their potential applications. To this end, resorcinol-formaldehyde microspheres (RFS) were prepared in high yield through the modified Stöber method, utilizing resorcinol and formaldehyde as carbon sources, ammonia as a catalyst, and sodium dodecyl benzenesulfonate (SDBS) as a soft template. The resulting RFS were then carbonized to obtain high yield CS.

Effect of Fiber Characteristics on the Structure and Properties of Quartz Fiber Felt Reinforced Silica-Polybenzoxazine Aerogel Composites.

Fiber-reinforced aerogel composites are widely used for thermal protection. The properties of the fibers play a critical role in determining the structure and properties of the final aerogel composite. However, the effects of the fiber's characteristics on the structure and properties of the aerogel composite have rarely been studied.

Research Progress on Modification of Aerogels by Chemical Vapor Deposition.

Aerogels are three-dimensional nanomaterials with low thermal conductivity, low density, high specific surface area, and high porosity. They have demonstrated remarkable performance advantages in thermal insulation, catalysis, and adsorption in recent years. However, their inherent brittleness and weak skeletal structure limit their applications.

TiN as Radical Scavenger in Fe─N─C Aerogel Oxygen Reduction Catalyst for Durable Fuel Cell.

Fe─N─C is the most promising alternative to platinum-based catalysts to lower the cost of proton-exchange-membrane fuel cell (PEMFC). However, the deficient durability of Fe─N─C has hindered their application. Herein, a TiN-doped Fe─N─C (Fe─N─C/TiN) is elaborately synthesized via the sol-gel method for the oxygen-reduction reaction (ORR) in PEMFC.

Boosting the Performance of Low-Platinum Fuel Cells via a Hierarchical and Interconnected Porous Carbon Support.

The design of a low-platinum (Pt) proton-exchange-membrane fuel cell (PEMFC) can reduce its high cost. However, the development of a low-Pt PEMFC is severely hindered by the high oxygen transfer resistance in the catalyst layer. Herein, a carbon with interconnected and hierarchical pores is synthesized as a support for the low-Pt catalyst to lower the oxygen transfer resistance.

Ultralight elastic AlO nanorod-graphene aerogel for pressure sensing and thermal superinsulation.

Novel nanorod aerogels have gained tremendous attention owing to their unique structure. However, the intrinsic brittleness of ceramics still severely limits their further functionalization and application. Here, based on the self-assembly between one-dimensional (1D) AlO nanorods and two-dimensional (2D) graphene sheets, lamellar binary AlO nanorod-graphene aerogels (ANGAs) were prepared by the bidirectional freeze-drying technique.

Ultralight Ceramic Fiber Aerogel for High-Temperature Thermal Superinsulation.

Emerging fiber aerogels with excellent mechanical properties are considered as promising thermal insulation materials. However, their applications in extreme environments are hindered by unsatisfactory high-temperature thermal insulation properties resulting from severely increased radiative heat transfer. Here, numerical simulations are innovatively employed for structural design of fiber aerogels, demonstrating that adding SiC opacifiers to directionally arranged ZrO fiber aerogels (SZFAs) can substantially reduce high-temperature thermal conductivity.

Single-Atom and Hierarchical-Pore Aerogel Confinement Strategy for Low-Platinum Fuel Cells.

Achieving high catalytic performance through the lowest possible content of platinum (Pt) is the key to cost reduction of proton-exchange-membrane fuel cells (PEMFCs). However, lowering the Pt loading in PEMFCs leads to the high mass-transport resistance of oxygen originating from the limited active sites, and causes less stability of the catalysts due to Pt size growth after long-time operation. Herein, Pt-metal/metal-N-C aerogel catalysts are designed that substantially reduce oxygen-related mass transport resistance and have long-term durability.

Bionic Aerogel with a Lotus Leaf-like Structure for Efficient Oil-Water Separation and Electromagnetic Interference Shielding.

Increasing pollution from industrial wastewater containing oils or organic solvents poses a serious threat to both the environment and human health. Compared to complex chemical modifications, bionic aerogels with intrinsic hydrophobic properties exhibit better durability and are considered as ideal adsorbents for oil-water separation. However, the construction of biomimetic three-dimensional (3D) structures by simple methods is still a great challenge.

Preparation of a carbon fibre-reinforced carbon aerogel and its application as a high-temperature thermal insulator.

Carbon aerogels (CAs) have attracted attention in thermal insulation. However, the traditional sol-gel method for preparing them involves time-consuming solvent exchange and rigorous supercritical drying processes, and the obtained CAs are brittle and crumble easily. To address these problems, a carbon fibre-reinforced carbon aerogel (CF/CA) was prepared combining a resorcinol-furfural (RF) gel containing a salt (ZnCl) with polyacrylonitrile (PAN) fiber felt.

Versatile Thermal-Solidifying Direct-Write Assembly towards Heat-Resistant 3D-Printed Ceramic Aerogels for Thermal Insulation.

Ceramic aerogels have great potential in the areas of thermal insulation, catalysis, filtration, environmental remediation, energy storage, etc. However, the conventional shaping and post-processing of ceramic aerogels are plagued by their brittleness due to the inefficient neck connection of oxide ceramic nanoparticles. Here a versatile thermal-solidifying direct-ink-writing has been proposed for fabricating heat-resistant ceramic aerogels.

Three-Dimensional-Printed Silica Aerogels for Thermal Insulation by Directly Writing Temperature-Induced Solidifiable Inks.

Silica aerogels are attractive materials for various applications due to their exceptional performances and open porous structure. Especially in thermal management, silica aerogels with low thermal conductivity need to be processed into customized structures and shapes for accurate installation on protected parts, which plays an important role in high-efficiency insulation. However, traditional subtractive manufacturing of silica aerogels with complex geometric architectures and high-precision shapes has remained challenging since the intrinsic ceramic brittleness of silica aerogels.

Facile Preparation of High Strength Silica Aerogel Composites via a Water Solvent System and Ambient Pressure Drying without Surface Modification or Solvent Replacement.

To further reduce the manufacturing cost and improve safety, silica aerogel composites (SAC) with low density and low thermal conductivity synthesized via ambient pressure drying (APD) technology have gradually become one of the most focused research areas. As a solvent, ethanol is flammable and needs to be replaced by other low surface tension solvents, which is dangerous and time-consuming. Therefore, the key steps of solvent replacement and surface modification in the APD process need to be simplified.

Printed aerogels: chemistry, processing, and applications.

As an extraordinarily lightweight and porous functional nanomaterial family, aerogels have attracted considerable interest in academia and industry in recent decades. Despite the application scopes, the modest mechanical durability of aerogels makes their processing and operation challenging, in particular, for situations demanding intricate physical structures. "Bottom-up" additive manufacturing technology has the potential to address this drawback.

Compressible, Flame-Resistant and Thermally Insulating Fiber-Reinforced Polybenzoxazine Aerogel Composites.

The preparation of novel polymer aerogel materials with enhanced flame-retardancy, superior thermal insulation and mechanical strength is of great practical significance in energy-savings and fire-prevention for buildings. Herein, we reported the fiber-reinforced polybenzoxazine (PBO) aerogel composites with flame retardance and thermal insulation, which were prepared under room temperature and atmospheric pressure, and using 4,4'-diaminodiphenlymethane (MDA) benzoxazine monomer as the raw material and oxalic acid (OA) as the catalyst. Several outstanding attributes were achieved in the aerogel composites, such as relatively low thermal conductivity (0.

Elastic methyltrimethoxysilane based silica aerogels reinforced with polyvinylmethyldimethoxysilane.

Native silica aerogels are fragile and brittle, which prevents their wider utility. For designing more durable and stronger silica aerogels, polyvinylmethyldimethoxysilane (PVMDMS) polymers as effective and multifunctional reinforcing agents were used to strengthen methyltrimethoxysilane based silica aerogels (MSAs). The PVMDMS polymer, which was composed of long-chain aliphatic hydrocarbons and organic side-chain methyl and alkoxysilane groups, was integrated into silica networks a simple sol-gel process.

Thermal conductivity of polyvinylpolymethylsiloxane aerogels with high specific surface area.

The traditional SiO aerogels are difficult to apply in the fields of energy storage and heat insulation due to their poor mechanical properties. In order to deal with this issue, the polyvinylpolymethylsiloxane aerogel (PVPMSA) materials with fine mechanical flexibility and excellent thermal insulation properties are suitable substitutions. In this paper, the double cross-linking organic-inorganic hybrid PVPMSAs were prepared through the processes of free radical polymerization and hydrolytic polycondensation.

Controlling the microstructure of resorcinol-furfural aerogels and derived carbon aerogels the salt templating approach.

The control strategy for the microstructure of resorcinol-furfural (RF) aerogels and derived carbon aerogels is attracting attention in different applications such as adsorbents, electrochemical electrodes, thermal insulation and so on. In this work, RF aerogels with abundant micropores were synthesized successfully by the sol-gel process using resorcinol (R) and furfural (F) as monomers, methanol (M) as the solvent, hexamethylenetetramine (H) as the catalyst, and zinc chloride (Z) as a salt template. The RF aerogels with micro specific surface area up to 228.

Preparation and Properties of SiBCO Aerogel and Its Composites.

To obtain new high-temperature resistant composites that can meet the requirements of aircraft development for thermal insulation and mechanical properties, SiBCO aerogel composites were prepared by sol-gel, supercritical drying and high-temperature pyrolysis with trimethyl borate (TMB) or phenylboronic acid (PBA) as the boron source and mullite fiber as reinforcement. The structure and composition of the SiBCO aerogel and its composites were characterized with SEM, FT-IR, ICP and nitrogen adsorption tests. The specific surface area of the SiBCO aerogel is 293.

Edge Defect Engineering of Nitrogen-Doped Carbon for Oxygen Electrocatalysts in Zn-Air Batteries.

Metal-free bifunctional oxygen electrocatalysts are extremely critical to the advanced energy conversion devices, such as high energy metal-air batteries. Effective tuning of edge defects and electronic density on carbon materials via simple methods is especially attractive. In this work, a facile alkali activation method has been proposed to prepare carbon with large specific surface area and optimized porosity.

Self-Sacrificial Salt Templating: Simple Auxiliary Control over the Nanoporous Structure of Porous Carbon Monoliths Prepared through the Solvothermal Route.

The conventional sol-gel method for preparing porous carbons is tedious and high-cost to prepare porous carbons and the control over the nanoporous architecture by solvents and carbonization is restricted. A simple and novel self-sacrificial salt templating method was first presented to adjust the microporous structure of porous carbon monoliths synthesized via the solvothermal method. Apart from good monolithic appearance, the solvothermal route allowed for ambient drying because it made sure that the polymerization reaction was completed quickly and thoroughly.

Preparation and anti-oxidation performance of AlO-containing TaSi-MoSi-borosilicate glass coating on porous SiCO ceramic composites for thermal protection.

In order to improve the thermal oxidation resistance of carbon fiber-reinforced porous silicon oxycarbide (SiCO) ceramic composites, an AlO-containing TaSi-MoSi-borosilicate glass coating was formed on the surface of the composites brushing and sintering. The anti-oxidation property of the coated composites at 1873 K was investigated. Microstructures and chemical compositions of the sample before and after anti-oxidation test were determined using XRD, SEM and EDS.

Study on Thermal Conductivities of Aromatic Polyimide Aerogels.

Polyimide aerogels for low density thermal insulation materials were produced by 4,4'-diaminodiphenyl ether and 3,3',4,4'-biphenyltetracarboxylic dianhydride, cross-linked with 1,3,5-triaminophenoxybenzene. The densities of obtained polyimide aerogels are between 0.081 and 0.

Carbon aerogel composites prepared by ambient drying and using oxidized polyacrylonitrile fibers as reinforcements.

Carbon fiber-reinforced carbon aerogel composites (C/CAs) for thermal insulators were prepared by copyrolysis of resorcinol-formaldehyde (RF) aerogels reinforced by oxidized polyacrylonitrile (PAN) fiber felts. The RF aerogel composites were obtained by impregnating PAN fiber felts with RF sols, then aging, ethanol exchanging, and drying at ambient pressure. Upon carbonization, the PAN fibers shrink with the RF aerogels, thus reducing the difference of shrinkage rates between the fiber reinforcements and the aerogel matrices, and resulting in C/CAs without any obvious cracks.