Three-dimensional Porous Composites Research Articles

Bacterial cellulose based three-dimensional porous composites with remarkable amphiphobic monolith properties for passive daytime radiative cooling

To tackle the daytime radiative cooling performance (DRCP) degradation of passive daytime radiative cooling materials (PDRCMs) due to contamination from aqueous or oily contaminants, modified three-dimensional porous composites of bacterial cellulose (BC) and barium sulfate (BaSO4) were fabricated by a unidirectional freeze-casting process and silanization modification. The modified BC/BaSO4 (M−BC/BaSO4) composites exhibited average reflectivity of 97.75%, average emissivity of 95.74%, and remarkable amphiphobic monolith properties with a water contact angle (WCA) and oily contact angle (OCA) of 154° and 145.5° for the surface and those of 153.5° and 143.5° for the internal section, respectively. They also exhibited insignificant changes in the DRCP before and after self-cleaning, achieving an average and maximum temperature drop of 10.40°C and 16.38°C before self-cleaning and those of 9.92°C and 16.40°C after self-cleaning, respectively. This work provides a new strategy for sustainable PDRCMs in practical applications.

Coupling ultrafine SiO2 nanoparticles with three-dimensional porous Ti3C2Tx MXene as anode materials for high-performance lithium-ion batteries

Silicon dioxide with high-capacity and abundant resource is regarded as a promising anode material for lithium-ion batteries, but the poor intrinsic electrical conductivity and large volume change during the discharge/charge cycles impede its practical application. Herein, a three-dimensional porous composite of Ti3C2Tx@SiO2 was fabricated with a low-temperature liquid phase method, and the ratio of SiO2 and Ti3C2Tx was regulated. The as-prepared A-MX@SiO2-2 with the optimal composition exhibits the best cycle performance (437.9 mAh g−1 after 1000 cycles at 0.1 A g−1) and rate performance (130.0 mA h g−1 at 2 A g−1), which are much higher than pure SiO2 and MXene. The excellent electrochemical performance can be ascribed to the synergistic effect of ultrafine SiO2 nanoparticles and three-dimensional porous Ti3C2Tx, which can shorten the Li+ transport pathway, accelerate electron transfer, and relieve the stress caused by the volume expansion of SiO2. The composite structure effectively inhibits both the aggregation of SiO2 and restacking of Ti3C2Tx. Furthermore, the in-situ formed SiO2 can firmly anchored on the surface of Ti3C2Tx nanosheet by robust interfacial bonding, which enhances the structural stability and conductivity. This research provides a feasible design strategy for synthesis of Ti3C2Tx@SiO2 composite to be employed as advanced energy storage materials.

In Situ Synthesis of CoCeSx Bimetallic Sulfide Nanoparticles on a Bi-Pyrene Terminated Molecular Wire Modified Graphene Surface for Supercapacitors.

The excellent electrical conductivity of graphene is due to its highly-conjugated structures. Manipulation of the electronic and mechanical properties of graphene can be achieved by controlling the destruction of its in-sheet conjugation system. Herein, we report the preparation of CoCeSx -SA@BPMW@RGO through π-π stacking interactions at the molecular level. In this study, sodium alginate was reacted with Co2+ and Ce3+ , and the composite was loaded onto a graphene surface. The graphene sheets were prepared using a bi-pyrene terminated molecular wire (BPMW) to avoid re-stacking of the grapheme sheets, thereby forming nanoscale spaces between sheets. The angle between the BPMW coplanar pyrene group and the phenyl group was 33.2°, and the graphene layer is supported in an oblique direction. Finally, a three-dimensional porous composite was obtained after annealing and vulcanization. The obtained CoCeSx -SA@BPMW@RGO exhibited excellent electrical conductivity and remarkable cycle stability. When the current density was 1 A g-1 , its specific capacitance was as high as 1004 F g-1 . BPMW modifies graphene through the synergistic effect of π-π stacking interaction and special structure to obtain excellent electrochemical performance. Moreover, a solid-state asymmetric supercapacitor device was fabricated based on the synthesized CoCeSx -SA@BPMW@RGO hybrid, which exhibited a power density of 979 W kg-1 at an energy density of 23.96 Wh kg-1 .

Synergetic effects of graphene-CoPc/silk fibroin three-dimensional porous composites as catalysts for acid red G degradation.

The disposal of dye wastewater is one of the hotspots of scientific research. Upon combining the ability of graphene to accelerate the hydroxyl radical generation with the Fenton system, it has shown a faster degradation rate and can be recycled, showing greater degradation efficiency than the traditional dye treatment method. Herein, a catalytic system based on the regenerated silk fibroin (SF) gel integrated with cobalt tetraaminophthalocyanine (CoTAPc)-grafted-reduced graphene oxide (RGO) sheets were fabricated, and its catalytic activity was assessed via the degradation of acid red G (ARG) at varying catalyst and H2O2 dosages, pH values, and temperatures. The results revealed that the three-dimensional (3D) porous RGO-CoTAPc/SF gel exhibited a much stronger catalytic behavior than the other arbitrary components due to its high surface area and synergetic hydroxyl radical generation efficiency, with the dye removal ratio by RGO-CoTAPc/SF being higher in an acidic medium than in an alkaline medium. It also increases with the increase in temperature and RGO-CoTAPc/SF and H2O2 dosages. Further, the catalytic oxidation process of ARG was determined, and the possible degradation mechanism of ARG has been discussed. Our results suggest that the composite materials with high catalytic activity can provide a reference for future Fenton-like catalytic systems.

Enhanced extracellular matrix synthesis using collagen dressings loaded with Artemisia absinthium plant extract

The aim of this study was to develop three-dimensional porous composites of collagen (Col) incorporating polyphenolic-rich wormwood extract and to investigate their interaction with human skin cells, in order to optimize wound healing treatments. The scaffolds’ ultrastructure was observed by scanning electron microscopy, and biodegradability and bioactive compounds release were investigated in physiologic environment. Interaction of composites in direct and indirect contact with human skin cells was evaluated using two in vitro experimental models. ColWE scaffolds presented high porosity, swelling degree, and increased stability against enzymatic degradation, compared to Col scaffold. Composite scaffolds incorporating higher quantities of wormwood extract allowed better control of polyphenolics release. ColWE 0.5 variant favored the attachment and proliferation of human dermal fibroblasts and keratinocyte cells. In addition, the composite scaffold stimulated the synthesis of skin extracellular matrix components. All these results demonstrated that ColWE composites with improved physico-chemical and biological properties could be used in advanced wound healing applications.

Correction "Three-Dimensional Phosphorus-Doped Graphitic-C3N4 Self-Assembly with NH2-Functionalized Carbon Composite Materials for Enhanced Oxygen Reduction Reaction".

Oxygen reduction reaction (ORR) is the major reaction that occurs at the cathodes of fuel cells and metal–air batteries. Development of inexpensive, active, and durable heteroatom doped carbon-based ORR catalysts can lead to significant cost reduction of these electrochemical energy devices, which therefore has recently attracted enormous research attentions. This work reports a three-dimensional porous composite (P-g-C3N4@NH2–CB) for the highly efficient ORR catalyst. P-g-C3N4@NH2–CB was prepared by mixing phosphorus-doped graphitic carbon nitride nanosheets (P-g-C3N4 NSs) with NH2-functionalized carbon black (NH2–CB) via a novel self-assembly approach. The NH2–CB was rationally chosen as the spacer that enables the self-assembled with the P-g-C3N4 NSs driven by the electrostatic interaction. The intercalation of NH2–CB induces the transformation of 2-D P-g-C3N4 NSs into a 3-D composites material of higher surface area, thereby exposing more ORR active sites. The P-g-C3N4@NH2–CB exhibited a remarkable OR...

Adsorption Performance and Mechanism of HZO@SGH for the Removal of Fluoride from Aqueous Solution

Three-dimensional porous composites based on hydrous zirconium oxide and self-assembled graphene hydrogels (HZO@SGH) were successfully synthesized via homogeneous precipitation. HZO@SGH was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) to investigate the morphology and the defluoridation mechanism. The adsorption performance and mechanism of HZO@SGH for fluoride was investigated via batch adsorption experiments. The results revealed that the adsorption capacity of HZO@SGH for fluoride was obviously higher than that of HZO or SGH singly. The adsorption data for fluoride onto HZO@SGH complied with the pseudo-second-order kinetic model, indicating that the adsorption rate was mainly controlled by chemical adsorption. The adsorption process could be described well with the Dubinin-Radushkevich isotherm model, as the maximum adsorption capacity was approximately 31.79 mg·g-1, which is higher than that of some zirconium-containing adsorbents, as previously reported. HZO@SGH showed excellent adsorption properties in the fluoride solution contained NO3-, Cl-, and a low concentration of SO42- (≤ 10 mg·L-1) at low pH (3-6.5). The preparation of HZO@SGH was convenient and environmentally friendly, as it was easily separated from the fluoride solution and did not cause secondary pollution. Hence, the prospect of HZO@SGH in practice was brilliant.

Durability evaluation of superhydrophobic copper foams for long-term oil-water separation

Superhydrophobic three-dimensional porous composites with good mechanical stability and high efficiency are promising candidates for oil-water separation application. Hence, several superhydrophobic copper foams were fabricated via the in situ growth of patterned Cu(OH)2 nanoneedles or ZnO nanocrystals (e.g. ZnO nanocones and ZnO nanorods) on the skeleton and followed by chemically modification. All the superhydrophobic copper foams showed efficient oil-water separation ability, especially the samples with ZnO nanorods arrays on the pre-nanostructured skeleton. The durability of superhydrophobic copper foams were then evaluated. Although the superhydrophobic samples kept separation efficiency higher than 95% after cycled evaluation, the pre-roughened copper foams exhibited the best performance against various damage among the samples. Microstructural evolution revealed that the coverage of the copper skeleton became from smooth swelling micro-crystals into rough nano-crystals after the pre-treatment of electrodepositing copper nanoparticles. The rough nanocrystals could not only avoid the formation of loose hierarchical structure, but also improve the binding force between patterned nanorods and the matrix. The fabricated closely-patterned ZnO nanorods could thus remain stable under the damage compared to others, presenting great mechanical robustness. Furthermore, we achieved a long-term efficient oil-water separation using the durable foams by periodic removal of residual oil in nanostructure gaps.

Three-dimensional porous graphene/polyaniline composites for high-rate electrochemical capacitors

Three-dimensional porous composites of reduced graphene oxide and polyaniline prepared by electro-codeposition exhibited much higher areal specific capacitances and greatly improved rate capability compared with those of their individual components.

Biomimetic strengthening polylactide scaffold materials for bone tissue engineering

In this paper, a new polylactide (PLA)-based scaffold composite by biomimetic synthesis was designed. The novel composite mainly consists of nano-hydroxyapatite (n-HA), which is the main inorganic content in natural bone tissue for the PLA. The crystal degree of the n-HA in the composite is low and the crystal size is very small, which is similar to that of natural bone. The compressive strength of the composite is higher than that of the PLA scaffold. Using the osteoblast culture technique, we detected cell behaviors on the biomaterial in vitro by SEM, and the cell affinity of the composite was found to be higher than that of the PLA scaffold. The biomimetic three-dimensional porous composite can serve as a kind of excellent scaffold material for bone tissue engineering because of its microstructure and properties.

Poly(α‐hydroxyl acids)/hydroxyapatite porous composites for bone‐tissue engineering. I. Preparation and morphology

Tissue engineering has shown great promise for creating biological alternatives for implants. In this approach, scaffolding plays a pivotal role. Hydroxyapatite mimics the natural bone mineral and has shown good bone-bonding properties. This paper describes the preparation and morphologies of three-dimensional porous composites from poly(L-lactic acid) (PLLA) or poly(D,L-lactic acid-co-glycolic acid) (PLGA) solution and hydroxyapatite (HAP). A thermally induced phase separation technique was used to create the highly porous composite scaffolds for bone-tissue engineering. Freeze drying of the phase-separated polymer/HAP/solvent mixtures produced hard and tough foams with a co-continuous structure of interconnected pores and a polymer/HAP composite skeleton. The microstructure of the pores and the walls was controlled by varying the polymer concentration, HAP content, quenching temperature, polymer, and solvent utilized. The porosity increased with decreasing polymer concentration and HAP content. Foams with porosity as high as 95% were achieved. Pore sizes ranging from several microns to a few hundred microns were obtained. The composite foams showed a significant improvement in mechanical properties over pure polymer foams. They are promising scaffolds for bone-tissue engineering. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res, 44, 446–455, 1999.