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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field Emission from Porous Sponge-Like Graphene
摘要： Herein, a unique porous sponge-like structured graphene has been proposed as field emission emitter. The synthesis process, post treatment and characterizations of the porous sponge-like graphene have been described, and its field emission properties have been researched. Compared to other kind of reported graphene structures, relative low turn-on field could be achieved due to its wide spacing separated surface morphology and vertically stand graphene sheets field emitters.
关键词： sponge-like,porous,field emission,graphene
更新于2025-09-23 15:21:21
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Sulfur-doped porous graphitic carbon nitride heterojunction hybrids for enhanced photocatalytic H2 evolution
摘要： Graphitic carbon nitride (g-C3N4) is considered as an attractive, efficient and newly generated photocatalyst material owing to its distinct properties such as metal free, suitable band gap and high physicochemical stability. Nevertheless, the photocatalytic activity of pure g-C3N4 was limited by the fast recombination rate of photoinduced electron–hole pairs and relatively low specific surface area. In this study, we provide a new prospect to overcome the problem by using another suitable precursor urea-assisted copolymerization with thiourea which is expected to optimize the process of thermal condensation, inhibit agglomeration and improve the specific surface area; meanwhile, the formed isotype heterogeneous junction effectively inhibits charge carrier recombination. The formed g-C3N4 isotype heterojunction photocatalyst manifested significant improvement photocatalytic hydrogen production than the single and pure g-C3N4 sample. This significant enhanced photocatalytic performance is mainly ascribed to inhibited recombination, enriched active site and enlarged specific surface area.
关键词： porous graphitic carbon nitride,heterojunction hybrids,photocatalytic H2 evolution,Sulfur-doped
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
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All-Poly(Ionic Liquid) Membrane-Derived Porous Carbon Membranes: Scalable Synthesis and Application for Photothermal Conversion in Seawater Desalination
摘要： Herein we introduce a straightforward, scalable and technologically relevant strategy to manufacture charged porous polymer membranes (CPMs) in a controllable manner. The pore sizes and porous architectures of CPMs are well-controlled by rational choice of anions in poly(ionic liquid)s (PILs). Continuously, heteroatom-doped hierarchically porous carbon membrane (HCMs) can be readily fabricated via morphology-maintaining carbonization of as-prepared CPMs. These HCMs being as photothermal membranes exhibited excellent performance for solar seawater desalination, representing a promising strategy to construct advanced functional nanomaterials for portable water production technologies.
关键词： porous carbon membrane,tailorable porous architecture,poly(ionic liquid),photothermal conversion,oxidative stability
更新于2025-09-23 15:21:01
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Correlating in-situ process monitoring data with the reduction in load bearing capacity of selective laser melted Tia??6Ala??4V porous biomaterials
摘要： Selective Laser Melting allows for the creation of intricate porous structures, that possess favourable biological properties. These structures are known as porous biomaterials. The focus of this paper is to evaluate the use of an in-line photodiode based process monitoring system, for the monitoring of the operational behaviour of the laser, and to correlate this with the resultant parts mechanical performance. In this study the production scale Renishaw 500M was used to produce porous structures, using Ti–6Al–4V feedstock powder. During the process, a co-axial process monitoring system was utilised to generate data relating to both the meltpool and the operational behaviour of the laser. An advanced scanning technique was used to produce the structures, whereby the laser parameters determine the strut dimensions. In this study, the laser input energy was reduced by 33%, 66% and 100%, at specific layers within the structures. Computer Tomography and Scanning Electron Microscopy was utilised to characterise the affected struts within the structures, while quasi-static compression testing was used to determine the structure’s mechanical properties. It was demonstrated that as the level of input energy decreased and the number of affected layers increased, a corresponding decrease in the load bearing capacity of the structures occurred. With the structures experiencing a significant loss in strength also exhibiting a change in the failure mode during compression testing. Data generated during the processing of such structures was compared to the data generated during the processing of control structures, with the difference between the two been calculated on a layer-by-layer basis. A clear correlation was demonstrated between the total level of deviation between the two signal sets and a reduction in the load bearing capacity of the structures. This indicates that by comparing build data to a benchmark data set, valuable information relating to the structural integrity of the porous structures can be obtained.
关键词： Porous structures,Selective laser melting,Process monitoring
更新于2025-09-23 15:21:01
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Laser induced self-N-doped porous graphene as an electrochemical biosensor for femtomolar miRNA detection
摘要： We report a sensitive, yet low-cost biosensor based on laser induced graphene for femtomolar microRNA (miRNA) detection. Combined with the miRNA extraction and magnetic isolation process, the target miRNAs were purified for further detection using laser induced graphene sensor. The laser induced graphene was prepared by direct laser writing on commercial polyimide (PI) and patterned via a computer-aided design system as an electrode for electrochemical biosensing. We found that the laser reduction of PI resulted in nitrogen-doped porous graphene, not only improving its conductivity but also its sensitivity to nucleic acids. Preeclampsia specific miRNA hsa-miR-486-5p was magnetically purified and directly adsorbed on the surface of graphene electrode via graphene-miRNA affinity interaction. Surface attached miRNAs were then electrochemically quantified using [Fe(CN)6]3-/4- redox system. Our assay demonstrates detection of miRNA has-miR-486-5p up to concentrations as low as 10 fM with excellent reproducibility. Owing to its facile fabrication, low cost and high performance, the laser induced N-doped graphene biosensor presented here shows great potential for applications in detecting miRNA in biomedical applications.
关键词： electrochemical biosensor,porous graphene,laser induced graphene,nitrogen-doped,miRNA detection
更新于2025-09-23 15:21:01
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Customizable fabrication for auxetic graphene assembled macrofilms with high conductivity and flexibility
摘要： Auxetic materials with negative Poisson's ratios unusually exhibit intuitive mechanical behaviors, such as cross-section expansion instead of contraction during tension. Such behaviors are interesting because they may enhance unusual mechanical properties. However, controllable preparation of materials with negative Poisson's ratio is still a major challenge. In this study, we report the synthesis of a flexible auxetic graphene assembled macrofilm (GAMF) from graphene oxide nanosheets by a thermal annealing and press assistant method. The obtained materials exhibit good flexibility and significantly wide tunable negative Poisson’s ratios ranging from -0.11 to -0.53. We also develop a reconstruction model for characterization the uniaxial tension of GAMF based on X-ray tomographic images. The tensile simulation result predicts the function relationship between Poisson's ratio and critical thickness of pore channels, which is in good agreement with the experimental data. As a result, an effective tunable way is proposed for customizable fabrication of GAMF with tunable negative Poisson's ratios, and the GAMF materials with good flexibility, high electrical conductivity and superior auxetic behavior looks promising for future development of wearable electronics.
关键词： prediction of tunable Poisson’s ratio,porous graphene film,Auxetic materials,negative Poisson’s ratio
更新于2025-09-23 15:21:01
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Photocatalytic degradation of tetracycline hydrochloride over rugby-like ?2-Ga <sub/>2</sub> O <sub/>3</sub> with a 3D hierarchically assembled porous structure for environmental remediation
摘要： A novel rugby-like β-Ga2O3 with 3D hierarchically assembled porous structures was successfully constructed through a facile precipitation-calcination method. The synthesized Ga2O3 materials were used to the photocatalytic degradation of tetracycline hydrochloride (TC·HCl) and the effects of calcination temperature on photocatalytic activity were discussed. The conversions of TC·HCl over Ga2O3-900 was 99.0% for Ga2O3-900 after 25 min UV-light irradiation, which was higher than those of commercial Ga2O3 (71.2%) and P25 (82.9%). The best photocatalytic activity of Ga2O3-900 could be attributed to the large specific surface area, intrinsic electronic properties and stable 3D hierarchically assembled porous structure. Based on the liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) analysis, the photocatalytic mechanism of Ga2O3 and feasible degradation pathway of TC·HCl were proposed. We believe that the present study can exploit an effective avenue to design the photocatalysts with 3D hierarchical porous structures to meet ever-increasing environmental remediation requirements.
关键词： β-Ga2O3,photodegradation pathway,nano-porous structures,tetracycline hydrochloride,optical properties
更新于2025-09-23 15:21:01
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Lignin-controlled photocatalyst of porous BiVO4-C nanocomposite for enhancing photocatalytic activity toward pollutant under visible-light
摘要： Explorations of biomass materials have emerged as a novel strategy to control the synthesis of semiconductor and improve the photocatalytic performance. Here, a lignin-derived porous structure of BiVO4-C nanocomposite was prepared via one-step hydrothermal approach. In the preparation process, lignin not only effectively controlled the growth of BiVO4 but also carbonized to form a porous structure of biochar-based semiconductor photocatalyst. The studies demonstrated that the BiVO4-C nanocomposite have enhanced photocatalytic activity due to the departure of electron-hole pairs and charge migration. These insights provided useful insight for the design of efficient biomass-based photocatalyst for environmental protection and green energy.
关键词： One-step hydrothermal,Biomass,Photocatalytic,BiVO4,Porous
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Hybrid III-V/SiGe solar cells on Si substrates and porous Si substrates
摘要： A tandem GaAsP/SiGe solar cell has been developed employing group-IV reverse buffer layers grown on silicon substrates with a subsurface porous layer. Reverse buffer layers facilitate a reduction in the threading dislocation density with limited thicknesses, but ease the appearance of cracks, as observed in previous designs grown on regular Si substrates. In this new design, a porous silicon layer has been incorporated close to the substrate surface. The ductility of this layer helps repress the propagation of cracks, diminishing the problems of low shunt resistance and thus improving solar cell performance. The first results of this new architecture are presented here.
关键词： tandem on silicon,porous silicon,reverse buffer layers,III-V on silicon,GaAsP/SiGe
更新于2025-09-23 15:21:01