- 标题
- 摘要
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- 实验方案
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Development of Graphitic Domains in Carbon Foams for High Efficient Electro/Photo-to-Thermal Energy Conversion Phase Change Composites
摘要： In this research work, hierarchical porous carbon foams (CFs) with high surface area and three dimensionally (3D) interconnected macro/meso/microporous structures were prepared through pyrolysis of stabilized poly(acrylonitrile-co-divinylbenzene) P(AN-co-DVB) polyHIPE foams at 900 °C under nitrogen atmosphere. The prepared CFs revealed high surface area (540 m2 g-1), semi-ordered nanoporosity, high electrical conductivity (470 S m-1) and high graphitization degree. Further, HR-TEM observation of CFs revealed the formation of graphitic domains in the structures. The obtained CFs were employed for encapsulation of phase change materials (PCMs) e.g. paraffin (PA) and polyethylene glycol (PEG). The prepared PCMs composites revealed the excellent reversible thermal/chemical stability after frequent 200 heating/cooling cycles. Black CF/PA and CF/PEG composites can be promising structures to driven either by applying a small voltage (3-3.6 V) with high electric-to thermal efficiency (up to 85%) or by irradiating with sunlight with high photo-to thermal efficiency (up to around 91%).
关键词： paraffin and poly ethylene glycol,carbon foam,phase change materials
更新于2025-09-23 15:23:52
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Radiative characteristics of Voronoi open-cell foams made from semitransparent media
摘要： The radiative characterization of open-cell foams made from semitransparent solids is more complex than that made from opaque media. This study aims to understand how the component radiative properties and structural parameters of such open-cell foams affect their radiative characteristics. A radiative transfer model was established in the limit of geometric optics for the radiative characterization of a family of numerically generated Voronoi foams with open cells. It considers the reflection and refraction at the solid surface and the transmission, absorption and scattering process inside the solid phase. It is found that when the solid phase is in reality partially transparent, the opaque solid assumption will lead to inaccurate outcomes. Strongly scattering solid phase may cause much radiative energy to be rejected via reflection behavior, which will weaken the absorptive capability of the foam sheets as radiation absorbers. In addition, the radiative transfer model established was applied in three popular ceramic foams (alumina, silicon carbide and zirconia). The model shows advances in the field of analyzing and explaining the spectral radiative characteristics of ceramic foams. The present work can provide useful guidance when open-cell foams made from semitransparent media become potential candidates for thermal applications.
关键词： Voronoi tessellation,Radiative characterization,Ceramic foam,Semitransparent
更新于2025-09-23 15:23:52
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A novel SiC nanowire aerogel consisted of ultra long SiC nanowires
摘要： SiC nanowire aerogel (SNA) with highly porous 3D nanowire architecture was synthesized by polymer pyrolysis chemical vapor deposition (PPCVD) process to deposit SiC nanowires in the pores of carbon foam, followed by high temperature oxidation of carbon foam. The microstructure of the prepared SNA was characterized by SEM, TEM and a large number of interweaving SiC nanowires with a diameter of 80-100 nm and a length of hundreds of micrometers form the highly porous 3D nanowire architecture of SNA. The prepared SNA possesses the performance combination of ultra-low density (30±7 mg·cm-3), high-temperature oxidation resistance (750 °C), noncombustible and fire resistance property in the fire, excellent thermal insulating property (0.03 W·m-1·k-1 at room temperature in He) and compressive strength of 0.11 MPa, which is applicable as high-temperature heat insulator, ceramic matrix composite, high temperature flue gas filter, fire-proofing material and catalyst carrier.
关键词： Carbon foam,Aerogel,SiC nanowire,CVD
更新于2025-09-23 15:23:52
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Low-density PMMA/MAM nanocellular polymers using low MAM contents: Production and characterization
摘要： Low-density nanocellular polymers are required to take advantage of the full potential of these materials as high efficient thermal insulators. However, their production is still a challenging task. One promising approach is the use of nanostructured polymer blends of poly(methyl methacrylate) (PMMA) and a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM), which are useful for promoting nucleation but seem to present a severe drawback, as apparently avoid low relative densities. In this work, new strategies to overcome this limitation and produce low-density nanocellular materials based on these blends are investigated. First, the effect of very low amounts of the MAM copolymer is analysed. It is detected that nanostructuration can be prevented using low copolymer contents, but nucleation is still enhanced as a result of the copolymer molecules with high CO2 affinity dispersed in the matrix, so nanocellular polymers are obtained using very low percentages of the copolymer. Second, the influence of the foaming temperature is studied. Results show that for systems in which there is not a clear nanostructuration, cells can grow more freely and smaller relative densities can be achieved. For these studies, blends of PMMA with MAM with copolymer contents from 10 wt% and as low as 0.1 wt% are used. For the first time, the production strategies proposed in this work have allowed obtaining low density (relative density 0.23) nanocellular polymers based on PMMA/MAM blends.
关键词： nanostructuration,gas dissolution foaming,PMMA,MAM,block copolymer,nanocellular polymer,nanocellular foam
更新于2025-09-23 15:23:52
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Selective recovery of indium via continuous counter-current foam separation from sulfuric acid solutions I – Application of anionic organophosphate surfactant as metal collector
摘要： Continuous counter-current foam separation (CCFS) with simultaneous injections of metal and surfactant solutions respectively into rising foam bed was applied to In(III) recovery from sulfuric acid solutions containing ternary metal ions of In/Cu/Zn. Through the screening tests of the surfactants in both conventional batch foam separation and CCFS, anionic organophosphate surfactant which has similar structure to phosphoric acid extractant (D2EHPA) was selected as the metal collector, with an addition of a nonionic co-surfactant as the foam stabilizer. The optimized surfactant combination was shown anionic A219B/nonionic POOE20 in this study; the complete recovery of In(III) was attained with the enrichment ratio of 5.5, whereas those of the other metals were suppressed in trace level, resulting in the excellent selective recovery. Moreover, metal solutions of quaternary In/Fe/Cu/Zn were also examined, and a dose of reductant for interfering Fe(III) into the metal solution was executed for improving the separation efficiency; the dose of ascorbic acid could invert the affinity order of A219B from Fe > In to In > Fe. The percent recovery and enrichment ratio of In(III) were 97% and 5.5, while the separation factors of In/Fe, In/Cu and In/Zn were 93, 1300 and 1300 respectively. This is our first favorable case for expanding the choice range of target metal ions in CCFS using anionic surfactants.
关键词： Foam fractionation,Indium recovery,Anionic organophosphate surfactant,Phosphorus acid extractant,Foam separation
更新于2025-09-23 15:22:29
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Three-Dimensional Graphene Interconnected Structure, Fabrication Methods and Applications: Review
摘要： Enormous amounts of research and development are currently underway in the arena of improving three-dimensional graphene and graphene oxide networks for use as foams, sponges and aerogels for a wide range of applications. The underlying reason for the interest in 3D graphene can be attributed to the splendid intrinsic and extrinsic properties brought as a result of the 3D porous structures which has given rise to high specific surface areas, good mechanical strength, fast mass and electron movement. Therefore a review about the present modes of fabrication, material properties and the applications of 3D graphene with strong emphasis on highly efficient graphene sponges and graphene foams is expounded. Following on from this, a concrete understanding of the fabrication of functionalized graphene aerogel for use in oil water separation will be addressed. To add on, the superiority of three-dimensional (3D) graphene based macro porous architectures, as an absorbent in comparison to various sorbent materials will be scrutinized. Furthermore, it was concluded that although large amounts of research and developments have been achieved thus far, there is still some room for improvement. In fact the benefits of these improvements will be applicable in a wide range of applications ranging from: high sensitivity gas detectors, super capacitors, lithium ion batteries, oil-water separators to name a few.
关键词： GS (Graphene sponge),GO (Graphene oxide),GF (Graphene foam)
更新于2025-09-23 15:22:29
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Bonded-luminescent foam based on europium complexes as a reversible copper (II) ions sensor in pure water
摘要： Developing novel lanthanide complexes to rapidly and reliably sensing Cu2+ ions in pure water is highly challenging. Here, a series long luminescence lifetime luminescent Eu-complex polyurethane foams (Eu-PUFs) porous material by simple one-step co-polycondensation reaction has been successfully assembled. The photoluminescence (PL) results indicated that the pure red emission from Eu3+ ions is selectively quenched upon addition of Cu2+ ions, and barely any interference by other metal ions in pure water, thus making Eu-PUFs as a potential Cu2+ ions sensing material. The original luminescent intensity of Eu3+ ions located 617nm can be recovered about 84% by washing of ethylenediaminetetraacetic acid (EDTA) there times, indicating the sensing ability of Eu-PUFs is highly reversible. Due to the probe molecules Eu (TTA)3 ? Phen-NH2 was bonded into Eu-PUFs through covalent bond linker, so the Eu-PUFs sensors can be utilized to detection of Cu2+ ions in pure water multiple times (more than 20 times) without much effect on the sensitivity, and the limitation of detection (LOD) for Cu2+ in pure water is as low as 0.28 μM. All above mentioned results revealed these Eu-PUFs are excellent and potential Cu2+ ions sensing material in pure water and will be widely used in analytical and biological application fields.
关键词： copper (II) ions detection,fluorescence quenching,Europium complexes,Bonded-luminescent foam
更新于2025-09-23 15:22:29
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Observation of stimulated emission from Rhodamine 6G-polymer aggregate adsorbed at foam interfaces
摘要： This paper reports for the first time the observation of stimulated emissions from the gas–liquid interface between two adjacent bubbles in highly ordered foams containing Rhodamine 6 G and surfactant. Stimulated emissions centred at 595 nm were observed when a monolayer of foam (～liquid fraction 0.11), placed on a highly reflective surface, was pumped with a 532 nm continuous wave laser directed along ～45° from the direction perpendicular to the substrate. Additionally, using confocal microscopy and micro-photoluminescence, it was found that the liquid fraction of the foam, the gap between two adjacent bubbles and the incidence angle of the laser are important parameters in guiding the light and promoting stimulated emissions at the interface. The adsorption of the polymer and dye increased the local concentration at the narrowest gaps between pairs of bubbles, which led to the formation of hemispherical micelles-dye agglomerates. The presence of the micelles aggregation caused random scattering induced stimulated emission. These results could have a significant impact on a number of applications, such as photocatalytic conversion at bubble interfaces, where TiO2 can scatter light and hence reaction rates may be increased.
关键词： photocatalysis,Stimulated emission,interface,lasing,microbubbles,foam
更新于2025-09-23 15:22:29
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Experimental evaluation of volumetric solar absorbers – Ceramic foam vs. an innovative rotary disc absorber concept
摘要： This paper presents the experimental evaluation of two volumetric solar absorber concepts. It compares the thermal performance of conventional foam absorbers with that of an innovative rotary disc absorber design. The moving absorber showed advantages regarding air temperature stability at the outlet and better operability compared to the foam absorber. Unfortunately, it is shown that the innovative rotary disc design in its present form is not competitive, neither in terms of thermal performance, nor regarding mechanical reliability and robustness. The future task is therefore to optimize the mechanical design regarding thermal fatigue, in order to obtain a robust and durable rotary absorber that can be thoroughly evaluated experimentally.
关键词： volumetric solar absorbers,ceramic foam,thermal performance,rotary disc absorber,mechanical reliability
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Design and performance analysis of volumetric solar receiver based on porous foam ceramics
摘要： Volumetric solar receiver is one of three main categories of solar receivers. It has great application prospect due to the simple structure, high thermal efficiency, and the air exit temperature can reach above more than 800℃. The porous material is used instead of tube as absorber in volumetric solar receiver to heat the working medium, and the incident radiation can be absorbed gradually from outside to inside. In this study, an one-dimensional volumetric solar receiver calculating model based on porous foam ceramics is constructed. The temperature distributions and radiation absorption efficiencies at different conditions are analyzed, and a kind of secondary heating volumetric solar receiver is put forward to further improve its thermal efficiency. The results show that both the outlet air temperature and the depth for the temperature of air and ceramic solid reaching to stability decreases apparently with decrease of porosity of ceramic foam, but the temperature of front surface of the receiver increases gradually. With decrease of porous ceramic diameter, the air exit temperature decreases gradually, and the depth for the temperature of air and ceramic solid reaching to stability is decreasing, while, the diameter change has little effect on the temperature of front surface. The air exit temperature increases apparently with decrease of air flow rate and rise of inlet air temperature, and increases with increase of incident radiation intensity. The energy absorbing efficiency is decreasing with decrease of air flow rate and rise of inlet air temperature, and decreases with increase of incident radiation intensity. The presented secondary heating type of receiver can improve the energy absorbing efficiency, although the feasibility and economy of this consideration need further verification in future.
关键词： volumetric solar receiver,porous foam ceramics,temperature distribution,radiation absorption efficiency,secondary heating
更新于2025-09-23 15:21:21