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A hydrophilic polyacrylic acid hydrogel was formed in the millimeter-sized pores of Al2O3 foam ceramic by the polymerization of acrylic acid, and a large amount of nitrates precursor solution was adsorbed by the hydrogel via vacuum impregnation. A porous reticular CuO/ZnO/CeO2/ZrO2 catalyst with fine and uniform particles was obtained after 500 °C calcination. The ceramic loaded with pristine PAA hydrogel and loaded with absorbed hydrogel after 300 °C and 500 °C calcination were characterized to illustrate the formation mechanism of catalyst structure. The ceramic after 500 °C calcination was applied in a microreactor as catalyst support for methanol steam reforming to investigate the catalytic performance. Results showed that the porous reticular catalyst reduced the size of the catalytic channels and increased the number of effective catalytic channels simultaneously, resulting in a 100% methanol conversion rate, 0.288 mol/h H2 yield at 300 °C and an inlet methanol flow rate of 0.096 mol/h.

In this paper, 3D-SiC network skeleton with different structures was successfully constructed by regulating the microstructure of SiC foam ceramic struts via polyurethane replication technology combined with reactive infiltration of Si and solid-state sintering. Then, SiC/Al composites with 3D-interpenetrated network structure (3D-SiC/Al) were fabricated via vacuum pressure infiltration of Al alloy into the 3D-SiC skeleton, for application as electronic packaging. The effects of different skeleton structures on the thermal conductivity (TC), coefficient of thermal expansion (CTE), and flexural strength of the composites were investigated in detail. Furthermore, representative volume element (RVE) models of the 3D-SiC/Al composites were developed and their heat transfer properties and dimensional stability were also comparatively analyzed by finite element (FE) simulations. The results showed that the 3D-SiC/Al composites exhibited high TC of 196 W/m·K, low CTE of 8.03 × 10−6 K−1, and excellent flexural strength of 272 MPa. Low thermal deformation parameter (TDP) and Ashby map demonstrated that the synergistic effect of a complete 3D network skeleton and a clean well-bonded interface in the 3D-SiC/Al composites facilitated the integration of low CTE and high TC even at a low SiC content of 30 vol%. The FE results revealed a 63.5 % reduction in thermal stress and nearly an order of magnitude increase in heat flux for the RVE model of 3D-SiC (30 vol%)/Al composite compared to the RVE model of SiCP (60 vol%)/Al composite. This work provides a novel and scalable method for designing and synthesizing various composites for electronic packaging.

A CuO/ZnO/CeO2/ZrO2 catalyst slurry was prepared by mixing the catalyst powder, a polyvinyl alcohol aqueous solution, and glycerol. The slurry was coated on a Al2O3 foam ceramic support via a dip-c...

A highly permeable porous SiC ceramic membrane with multilayered unidirectional gradient pore microstructure was prepared by one-step freeze-casting process. The multilayer microstructures, mechanical properties and filtering performances of freeze-casting SiC ceramic membranes were controlled by optimizing the preparation process. It was found that with the increase of solid content from 30 vol% to 40 vol%, the directional pore channels gradually narrowed by about 50% and the mechanical properties increased from 0.47 MPa to 5.44 MPa. In addition, the increase of coarse particle content not only thickened the separation layer and the transition layer, but also widened the directional pore channel, which is beneficial to improve the permeability efficiency. When the coarse particle content of SiC ceramic membranes was 90%, the average pore size of separation layer, transition layer and lamellar structure was 5.52 μm, 7.63 μm and 36.09 μm, respectively. The maximum water permeability of S35C90 ceramic membrane reached up to 5.67 × 105 L/m2 h bar, and the rejection rate for ground calcium carbonate was 96.1%, confirming the superior perviousness and separation efficiency of freeze-casting ceramic membranes in the field of filtration.

In this paper, Ni/SiCxOy/P–SiC was prepared as the core part of microreactor for the hydrogen production of ethanol steam reforming (ESR). The Ni/SiCxOy catalysts were supported on the porous SiC ceramic (P–SiC) by the inverse microemulsion process using the xylene solution of polycarbosilane (PCS) and the aqueous solution of nickel nitrate as the oil phase and the water phase, respectively. The morphology, loading strength and in situ reduction of the catalysts, and the performance of the catalysts for hydrogen production from ESR were investigated. The Ni catalyst particles exhibited a nearly spherical morphology and a narrow particle size distribution with an average particle size of 127 nm. The combination of the Ni/SiCxOy catalysts and the P–SiC, characterized by ultrasonic vibration for 300 s, showed good strength. Moreover, the ESR with Ni/SiCxOy/P–SiC as the core part of the catalytic microreactor showed that the ethanol conversion and selectivity of H2 were still up to 91% and 72% after 210 min, respectively.

Two types of spherical zirconyl oxalate aqueous sols were successfully customized by a reverse micelles-mediated aqueous sol-gel process, and the sols were sequentially spin-coated on porous supports to prepare ZrO2 loose/tight bilayer ultrafiltration membranes. After three times of spin-coating process, a defect-free ZrO2 loose ultrafiltration membrane with pure water permeability of 110.5 ± 2.25 L m−2 h-1 bar-1, molecular weight cut-off (MWCO) of 16.5 kDa and excellent rejection of up to 97.5 % for bovine serum albumin was fabricated. Then, the loose ultrafiltration membrane was used as a substrate to prepare ZrO2 tight ultrafiltration membrane. Performances of tight ultrafiltration membrane regarding to permeability, retention of polyethylene glycol and treatment of dyes wastewater were evaluated. The tight ultrafiltration membrane with a thickness of 200 nm exhibited a pure water permeability of 22.5 ± 0.3 L m-2 h-1 bar-1 and MWCO of 1150 Da. Additionally, the rejections of methyl red and methyl orange by the tight ultrafiltration membrane were both

The composition and microstructure of materials play important roles in their thermal properties. In this study, the temperature and composition dependence of the thermal conductivity of MoSi2–RSiC composites with a special 3D interpenetrating network structure was investigated experimentally and numerically. A microstructure-based model was established using serial sectioning technology. The model could describe the connectivity and distribution characteristics of the two phases in the composites. Finite element simulation could accurately predict the effective thermal conductivity of the MoSi2–RSiC composites, with a deviation of 6.8%–9.6% between numerical and experimental results at different temperatures. Furthermore, a novel simplified model was developed to predict the effective thermal conductivity of the composites with a 3D interpenetrating network structure at different network inclusions. Landauer's effective medium percolation theory (EMPT) was used to verify the numerical values and analytical results. The calculation results of EMPT and the simplified model fit well with the experimental data of the composites with a high volume fraction matrix or measured below 600 K; the former was due to the effect of matrix density on the porosity and interfacial phase content of the composites, and the latter was due to the reduced difference in thermal conductivity coefficient among SiC, MoSi2 and the interfacial phase, and air with increased temperatures.

CuO/ZnO/CeO2/ZrO2 nanoflowers catalyst was grown on an Al2O3 foam ceramic by a one-step hydrothermal process, while a naked Al2O3 foam ceramic and an Al2O3 foam ceramic grown with ZnO nanorods that directly impregnated into the catalyst precursor solution were also fabricated simultaneously. The morphology, composition, redox property and specific surface area of catalysts on the three ceramics were investigated in detail. The catalyst-loaded ceramics were used as catalyst supports in a microreactor to study the catalytic performance for methanol steam reforming. Results showed that the microreactor with Al2O3 support grown with nanoflowers catalyst achieved 99.8% methanol conversion rate, 0.16 mol/h H2 flow rate at 310 °C, and an inlet methanol flow rate of 0.048 mol/h. Moreover, the microreactor exhibited 92% methanol conversion rate after 30 h continuous reaction.

Porous SiC ceramic as catalyst support with porous CuO/ZnO/CeO2/ZrO2 catalyst was fabricated via solution combustion method and used in a microreactor. A pore-in-pore hierarchical structure was formed on the support by using glycol as the fuel. The effects of fuel/nitrates molar ratio on the particle size, residual carbon, reducibility and structure of catalyst on the support were investigated. The optimal content of glycol was proposed and the catalytic performance of microreactor was further studied. Results showed that the catalyst loading amount was about 20% weight of the whole support and the loading intensity was strong. Moreover, the microreactor achieved a 100% methanol conversion rate at 280 °C and the conversion rate stayed around 95% after 30 h reaction by using the support over the optimal content of glycol, which exhibited excellent superiority in the methanol steam reforming process.

The SiC porous ceramics were successfully prepared by gelcasting process using Isobam as gelling agent. The pretreatment and surface modification of SiC was proposed to solve the problem that Isobam is difficult to crosslink and gelling with non-oxide ceramics. The SiC powder was firstly pre-oxidized, and then modified with a silane coupling agent to obtain a functional end group -NH2 on the surface, so that it can be crosslinked with Isobam to obtain a green body with uniform structure. With low amount of organic matter, no additional debinding procedure was required before sintering. The suitable oxide thickness was investigated, which shows a linear relationship with the original SiC particle size. Moreover, the solid content of the slurry was adjustable between 40 vol% and 52 vol%, and the porosity of the products varied between 50% and 60% after sintering.

Two kinds of low-cost alumina powders with irregular morphology were pretreated by spheroidization and the two spherical powders were used to prepare high-flux flat-sheet support and microfiltration (MF) membrane with high separation accuracy, respectively. It was found that the spheroidization pretreatment not only unified the morphology of alumina powder particles into spherical shape, but also narrowed the particle size distribution of the powders, which both were conducive to optimizing the performance of the as-prepared ceramic membranes. After sintering at 1350 °C, the open porosity, bending strength, average pore diameter and pure water permeability of alumina flat-sheet support from spheroidized alumina coarse powder were 44.3%, 36.3 MPa, 3.3 μm and 3240 L/h m2 bar, respectively. The slurry derived from spheroidized alumina fine powder was dip-coated on the flat-sheet support to prepare MF membrane. The crack-free MF membrane with a thickness of 23.5 μm had a pore diameter of 0.12 μm and pure water permeability of 850 L/h m2 bar. Additionally, the elaborated MF membrane was used to clarify aqueous suspension of carbon black with the maximum rejection rate of up to 99.7%, exhibiting excellent cleaning performance at the same time by completely restore the virgin permeate flux after backwash.

Al3+-doped TiO2 (AT) tight ultrafiltration membrane with stable anatase phase was prepared by a modified sol-gel process using butyl titanate and aluminum chloride as the precursor and aluminum source respectively. The removal of Alizarin red-S was investigated by filtration experiment. A dip-coating process on homemade flat Al2O3 intermediate layer by TiO2 sol followed by heat treatment was adopted to obtain the desired AT membrane. The addition of Al3+ inhibits the phase transformation of nanosized TiO2 from anatase to rutile and restrains the growth of crystallite, resulting in the pore size of the separation layer reducing to 3.5 nm. The prepared AT1-500 membrane exhibits enhanced hydrophilicity with no cracks or pinholes, and shows a water permeability of 9.6 L m-2 h−1 bar−1 and cut-off molecular weight (MWCO) of 4650 Da. The membrane demonstrated a retention rate of 96.9% for Alizarin Red-S (250 ppm) and maintained almost constant under repeated using.

Montmorillonite (MMT) has attracted widespread attention in the field of bone tissue engineering in recent years because of its interlayer domain structure. The progress of MMT application was reviewed in this article. Concretely, the application of MMT was mainly explained from the structural characteristics, mechanical strengthening mechanism, organic functionalization, and drug loading and release. Firstly, the polar polymer molecular chains are easily induced into the interlayer domain of MMT to form an interlock and achieve the mechanical strengthening of scaffold. Secondly, the “sandwich” sheet structure of MMT can be exfoliated into graphene-like MMT nanosheets, providing a nanostrengthening effect for polymer matrix. In addition, MMT’s interlayer domain provides a favorable environment for the loading and slow release of drugs, and it is an ideal platform for the functionalization of bone scaffolds. More importantly, MMT can be easily modified by cation exchange and chemical reaction to further improve the compatibility of composites: such as strengthening mechanical interlocking and nanostrengthening effects and achieving controllable loading and release of drugs. It is expected to provide a reference for improving the application of bone tissue engineering scaffolds.

8 mol% yttria-stabilized ZrO2 (8YSZ) nanofiltration (NF) membranes were prepared from size-controlled spherical ZrO2 nanoparticles with an average diameter of ˜10 nm and a particle roundness value greater than 0.90, and the nanoparticles were efficiently fabricated by a reverse micelles (RMs)-mediated sol-gel process. It was found that yttria doping not only suppressed the tetragonal to monoclinic (t-m) phase transition, ensuring the membranes integrity, but also decreased the tetragonal grain size, increased the specific surface area, narrowed the pore size distribution and thus optimized the NF performance. The as-prepared 8YSZ NF membranes with a thickness of ˜260 nm exhibited high NF performances, while the pure water permeability and molecular weight cut-off (MWCO) were 3.9-4.2 L m−2 h-1 bar-1 and 800 ± 50 Da respectively. In the treatment of pesticide wastewater, the removal rate of carbofuran by 8YSZ NF membranes was more than 82%, while the maximum removal rate could reach 89%. Furthermore, the contaminated membranes could be restored as ever after alkali wash and low-temperature calcination, implementing multiple reuses.