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Nanoscale complex-shaped colloids with tunable morphologies and fascinating properties have attracted the attention of numerous scientists for decades. Exploring facile synthetic strategies has always been the target for the large-scale production and practical use of these remarkable materials. Herein, we developed a one-step strategy to fabricate raspberry-like hollow periodic mesoporous organosilica (RHPMO) with tunable surface structures and specific surface area as high as 1628 m2 g−1. Unexpectedly, this preparation method shares a similar protocol as that of the classical one to make spherical PMO. The dynamic formation process of RHPMO has been detected by TEM. PMOs with solid cores were formed at the first stage, followed by a hollowing process owing to the tension of condensation among the silica precursor molecules. The final RHPMO nanoparticles were generated by controlling the condensation and the adsorption of the as-formed precursor/surfactant assemblies and covalently bonding them subsequently onto the surface of the core. The size of corona particles increased with the concentration of NH3·H2O, while low reaction temperatures were beneficial for the formation of RHPMO instead of spherical HPMO (SHPMO). A superhydrophobic coating was realized by depositing fluorine-modified RHPMO layers onto the glass substrate. The measured contact angle reached 153.9°. This one-step strategy for fabricating RHPMO may bring the new understandings of the formation mechanism of PMO and is expected to serve as a facile way for the large-scale production of raspberry-like functional silica spheres, which will thus open gates for more targeted applications.

Engineering highly porous SiC foams with interconnected cellular architecture and satisfactory compressive strength for the practical applications remains a challenging task. In the current work, SiC foams bonded by in-situ formed mullite phase were fabricated via polyurethane foaming using boehmite sol-coated SiC powder as the raw material. The strategy in the current work endowed the resultant products with ultrahigh porosity, interconnected pore structure, and a robust mullite bonding phase among the SiC particles. The resulting products with this cellular architecture possessed a high porosity level of 88.5% and maintained a robust compressive strength of 2.56 MPa. Our results showed that as-prepared products are promising for practical applications in the filtration, adsorption and catalytic areas.

Engineering high performance cellular ceramics with both ultralow density and satisfactory compressive strength for practical applications still represents a grand challenge. Herein, alumina-based cellular ceramics bonded by in-situ formed mullite phase were constructed by Al2O3–Si-boehmite particle-stabilized foams. The gelation of boehmite sol improved the stability and harnessed the deformation of dried Al2O3–Si composite foam. The oxidation of silicon and further generation of in-situ mullite phase enhanced the chemical bond between alumina particles on cell walls, resulting in the superior mechanical properties. As an exemplar, the resulting cellular ceramic possessed the robust compressive strength of 2.26 MPa at a high porosity of 87.8%. The gelation-assisted Al2O3–Si particle-stabilized foams provide a facile and convenient strategy for construction of composite ceramic foams with high porosity and robust strength.

A gelcasting system of alumina utilizing tartaric acid as the dispersant and glutaraldehyde as the crosslinker is reported, in which glutaraldehyde can polymerize itself and react with tartaric acid, thus forming a three-dimensional network. Measurement of zeta potential and viscosity shows good dispersion ability of tartaric acid. Shear modulus during gelation demonstrates its good gelation strength and fast gelation speed at room temperature. Moreover, an effective way to control the gelation speed is provided to improve the feasibility of this method. Results indicate that this gelcasting method has the advantages of low viscosity, small amounts of additives and short forming time and is a promising method to fabricate green bodies with large sizes and complex shapes.

Cellular ceramics with 3D network architecture are attracting ever-increasing attention because of their great application potential in multiple fields. Unfortunately, a daunting challenge still remains for fabricating such materials. A novel methodology is provided in the current work to construct cellular ZrO2 ceramics with such architecture by combining polyurethane foaming and chemical modification technology. Stearic acid grafted ZrO2 powder with improved dispersibility allows the successful assembly into the polyurethane porous framework. The obtained cellular materials possess a three-dimensional network architecture with windows on the cell wall. The resulting ZrO2 cellular ceramic with such unique structure exhibits a relatively high porosity (83.5%) and robust compressive strength (13.5 MPa), which outperforms most of the existing ZrO2-based counterparts. With above advantages, we envision that as-prepared products are promising for filter applications.

A new gelcasting approach of alumina inspired by Isobam was designed utilizing a polyelectrolyte dispersant named BTT, which is able to form cross-links via thiol-ene reaction with pentaerythritol tetrakis(2-mercaptoacetate). Measurement of zeta potential and viscosity shows good dispersion ability of BTT in 52 vol% alumina suspensions. The flow curves and shear modulus of wet green bodies during gelation demonstrate its high gelation strength in comparison with Isobam. The analysis of effects of addition of ammonium citrate tribasic into the system indicates that a polymer-particle double network is supposed to form during gelation. Elastic part and viscous part of gelation strength of the system are mainly dominated by interaction between polyelectrolyte and particles and cross-linking respectively, which accounts for the existence of both high gelation strength and flexibility of wet green bodies fabricated in this approach.

Nanofibrous aerogels constructed solely by ceramic components with temperature-invariant hyperelasticity could have broad technological implications in extreme environments. However, creating such materials has proven to be extremely challenging. Despite the results from laboratory, those aerogels are, unfortunately, still plagued with issues that would retard their further application: inferior structural integrity, failure at large compressive deformation, high production cost, and inability to withstand rigorous working conditions. To tackle these challenges, we report a facile strategy combining the chemical vapor deposition process and layer-by-layer self-assembly to construct hyperelastic SiC nanofibrous aerogels with three-dimensional porous architecture and improved structural integrity. The resultant aerogels outperform their natural counterparts and most state-of-the-art ceramic nanofibrous aerogels in their capability to quickly recover from large compressive deformation (50% strain), function in a wide range of temperatures, from -196 °C to 1100 °C in air, maintain high particle matter removal efficiency of >99.96%, and rapidly absorb various organic solvents and oils with high capacity and robust recoverability. Nanofibrous aerogels constructed by such a versatile method could provide fresh insights into the exploration of multifunctional nanofibrous aerogels for a variety of applications in extreme environments.

In the present work, Al2O3-Si3N4 porous ceramics with a cactus-like architecture were fabricated by calcining Al2O3-Si binary particle-stabilized foams in the nitrogen atmosphere. A large number of acicular Si3N4 nanobelts were constructed on the surface of cell walls as a consequence of CVD process to achieve an interlaced network. Such structure was beneficial to realize a high capture efficiency of particulate matters (PM) during filtration. Resultant products having a bulk density of 0.38 g/cm3 at an apparent porosity of 86% can potentially be applied as the air filters in environment field.

Nanofibrous aerogels constructed solely by ceramic components with temperature-invariant hyperelasticity could have broad technological implications in extreme environments. However, creating such materials has proven to be extremely challenging. Despite the results from laboratory, those aerogels are, unfortunately, still plagued with issues that would retard their further application: inferior structural integrity, failure at large compressive deformation, high production cost, and inability to withstand rigorous working conditions. To tackle these challenges, we report a facile strategy combining the chemical vapor deposition process and layer-by-layer self-assembly to construct hyperelastic SiC nanofibrous aerogels with three-dimensional porous architecture and improved structural integrity. The resultant aerogels outperform their natural counterparts and most state-of-the-art ceramic nanofibrous aerogels in their capability to quickly recover from large compressive deformation (50% strain), function in a wide range of temperatures, from -196 °C to 1100 °C in air, maintain high particle matter removal efficiency of99.96%, and rapidly absorb various organic solvents and oils with high capacity and robust recoverability. Nanofibrous aerogels constructed by such a versatile method could provide fresh insights into the exploration of multifunctional nanofibrous aerogels for a variety of applications in extreme environments.

In this paper, hollow gangue microspheres (GM) were introduced into a geopolymer matrix through a geopolymeric method; our aim was to synthesize a green and low-cost adsorbent (GM/KGP) for the removal of heavy metal ions (Cu2+, Cd2+, Zn2+, and Pb2+) from aqueous solutions. We investigated the microstructure of the GM/KGP adsorbent, as well as the effects of adsorbent dose, time, and temperature on adsorption behavior; moreover, an adsorption mechanism was proposed. The GM/KGP adsorbent possessed a typical broad amorphous structure and abundant O-containing functional groups on its surface. The adsorption of Cu2+, Cd2+, Zn2+, and Pb2+ onto the GM/KGP adsorbent fitted well to the pseudo-second-order kinetic model, while the equilibrium isotherm adsorption data were fitted well to the Langmuir equation. The adsorption mechanism GM/KGP was attributed to physical, chemical, and electrostatic attractions, as well as to ion exchange. We conclude that this novel adsorbent has great potential in removing heavy metal ions from contaminated wastewater.