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Hydroxy-carbonate-assisted synthesis of high porous graphitic carbon nitride with broken of hydrogen bonds as a highly efficient visible-light-driven photocatalyst
摘要： Graphite carbon nitride (g-C3N4) is a promising candidate as an efficient, affordable, and sustainable alternative photocatalyst owing to its unique physical and chemical properties. However, the photocatalytic activity of pristine g-C3N4 is still far below what is expected, because of its insufficient active site and high electron-hole recombination rates. Herein, we develop a novel strategy ― a one-step hydroxy-carbonate-assisted route ― to try to overcome these disadvantages in g-C3N4 nanosheets by creating substantial pores ranging from mesoporous to macropore, which are mainly caused by the partial breaking of hydrogen bonds and removing of magnesium oxide. Luxuriant pores in g-C3N4 not only serve as a reaction center by providing a large number of active sites at pore edges, but also effectively improve the photogenerated carrier separation by shortening their transfer lengths. The highly efficient visible-light photocatalytic activity of porous g-C3N4 nanosheets are demonstrated by degrading methyl blue (MB) and gentian violet (GV) as models, which its degradation rate constant is respectively more than 109 times and 12 times higher than those of pristine g-C3N4. Meanwhile, the high porous g-C3N4 has robust stability. The simple and effective strategy proposed here provides a direct route to highly functionalized g-C3N4 nanosheets and other layered semiconductors for various applications.
关键词： transfer of electrons,one-step route,high porous g-C3N4,hydroxy-carbonate-assisted route,photocatalysis
更新于2025-09-04 15:30:14
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Solution combustion synthesis of ZnO powders using various surfactants as fuel
摘要： Single phase ZnO powders were synthesized by solution combustion method using various surfactants as fuel. The effects of hydrocarbon tail length on the combustion behavior, phase evolution, morphology, optical properties, and photocatalytic activity were studied by thermal analysis, X-ray diffraction, electron microscopy, and photoluminescence spectroscopy techniques. The specific surface area and pore volume increased with the addition of citric acid as auxiliary fuel due to the increase of released gaseous products. ZnO powders obtained by mixed fuels show higher crystallinity and specific surface area, leading to the higher photodegradation of methylene blue under ultraviolet irradiation. Moreover, the photocatalytic activity increased in the presence of ZnO powders prepared by the longest hydrocarbon tail.
关键词： ZnO,Surfactant,Photocatalytic activity,Porous materials
更新于2025-09-04 15:30:14
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Interface-induced enhanced electromagnetic wave absorption property of metal-organic frameworks wrapped by graphene sheets
摘要： Most of metal–organic frameworks (MOFs) themselves have low electrical conductivities, leading to bad electromagnetic wave (EMW) absorption properties. Herein we found that the EMW absorption property of zeolitic imidazolate frameworks-8 (ZIF-8) particles was improved unexpectedly after coupling them with graphene sheets. Experimental results and theoretical calculations indicated that well-defined interfaces between ZIF-8 and the graphene sheets were crucial to the improvement of EMW absorption property. Our strategy presented here may open a new way for designing other MOFs based hybrids for high-performance EMW absorbers.
关键词： Porous structure,Graphene-organics composites,Metal–organic frameworks,Electromagnetic wave absorption,Multiple interfaces
更新于2025-09-04 15:30:14
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Fluorescent nanodiamond array deposition on porous anodized aluminum oxide using asperity assisted capillary force assembly
摘要： Array ordering of nanodiamonds with nitrogen-vacancy centers using porous anodized aluminum oxide (PAAO) templates is studied. Particle sorting and array formation are demonstrated with a polydisperse suspension of irregularly shaped diamonds with 28 nm number mean value diameter. The assembly is governed by a balance of withdrawal speed and evaporation driven particle flux, which is influenced by the asperities of the PAAO surface during the capillary and convective assembly dip-coating process. The resulting structures are dense (50 nm average center separation) isolated (non-touching) nanoparticle arrays with a size distribution that matches the topology of the template surface. The fluorescence signal is detected from arrays with an approximately 1:1 particle/pore filling ratio.
关键词： fluorescent nanodiamond,colloid assembly,porous anodic alumina,templated deposition
更新于2025-09-04 15:30:14
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A critical review of flexible and porous SERS sensors for analytical chemistry at the point-of-sample
摘要： For decades surface enhanced Raman spectroscopy (SERS) has been intensely investigated as a possible solution for performing analytical chemistry at the point of sample origin. Unfortunately, due to cost and usability constraints, conventional rigid SERS sensors and microfluidic SERS sensors have yet to make a significant impact outside of the realm of academics. However, the recently introduced flexible and porous paper-based SERS sensors are proving to be widely adaptable to realistic usage cases in the field. In contrast to rigid and microfluidic SERS sensors, paper SERS sensors feature (i) the potential for roll-to-roll manufacturing methods that enable low sensor cost, (ii) simple sample collection directly onto the sensor via swabbing or dipping, and (iii) equipment-free separations for sample cleanup. In this review we argue that movement to paper-based SERS sensors will finally enable point-of-sample analytical chemistry applications. In addition, we present and compare the numerous fabrication techniques for paper SERS sensors and we describe various sample collection and sample clean-up capabilities of paper SERS sensors, with a focus on how these features enable practical applications in the field. Finally, we present our expectations for the future, including emerging ideas inspired by paper SERS.
关键词： flexible sensors,paper-based sensors,SERS,porous sensors,point-of-sample,analytical chemistry
更新于2025-09-04 15:30:14
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Photosensitive carbon supercapacitor: Cavitated nanoporous carbon from iodine doped β–cyclodextryn
摘要： We have discovered a giant enhancement of the supercapacity (up to 4 times) under sun illumination of electrodes fabricated from cavitated nanoporous carbon being carbonized from a iodine doped β–cyclodexryn. This effect was achieved even without a frequently used KOH treatment and is caused by enhancement of effective activated surfaces. The synthesized cavitated nanoporous carbon exhibits principally different accumulative features at the carbon/electrolyte interface. Relationship between the porous structure, electronic properties of supramolecular nanoporous carbon and enhanced supercapacitance is explored. The impedance spectroscopy measurements (Nyquist diagram) apparently suggest a capacitance mechanism for the energy accumulation. Enhancement of the supercapacity is explained by light-generated carriers in low-dimensional nano-interfaces. In relevant mechanism an increasing concentration of delocalized electrons results in unlocking of the Helmholtz layer capacity.
关键词： nanoporous carbon,Nyquist diagrams,intercalation,Porous structures,pseudocapacity
更新于2025-09-04 15:30:14
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[ASME ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems collocated with the ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels - San Francisco, California, USA (Monday 6 July 2015)] Volume 1: Thermal Management - A Study on the Thermo-Fluid Simulation Model Using Porous Media in the Power Conversion System
摘要： When converting an electric power by an insulated-gate bipolar transistor (IGBT) module, the problem which is the heat generation in the IGBT module should be prudently considered in the design process. As an engineer reviews the cooling performance of power semi-conductor devices only at the component level, it is difficult to predict the reduction of airflow rates in the heat sink when power semi-conductor devices including the heat sink are integrated into the power conversion system. As the porous media model is adopted in the IGBT stack of the PCS, the problem that the meshes are heavily concentrated in the IGBT module including the heat sink, air, and IGBT/ diode chips can be evaded and the airflow rate which is reflected in the effect of flow resistance by all interior structures including the IGBT module is calculated. For the outdoor type PCS, the hotspot temperature on the heat sink of the simulation and experiment is 99.3 and 101.6 Celsius, respectively. The proposed numerical simulation model considerably accurately predicts the hotspot temperature on the heat sink and can earn benefits in terms of efforts of mesh generation and computation time.
关键词： porous media model,heat sink,thermo-fluid simulation,power conversion system,IGBT module
更新于2025-09-04 15:30:14
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Designing surface-enhanced Raman scattering (SERS) platforms beyond hotspot engineering: emerging opportunities in analyte manipulations and hybrid materials
摘要： Surface-enhanced Raman scattering (SERS) is a molecule-specific spectroscopic technique with diverse applications in (bio)chemistry, clinical diagnosis and toxin sensing. While hotspot engineering has expedited SERS development, it is still challenging to detect molecules with no specific affinity to plasmonic surfaces. With the aim of improving detection performances, we venture beyond hotspot engineering in this tutorial review and focus on emerging material design strategies to capture and confine analytes near SERS-active surfaces as well as various promising hybrid SERS platforms. We outline five major approaches to enhance SERS performance: (1) enlarging Raman scattering cross-sections of non-resonant molecules via chemical coupling reactions; (2) targeted chemical capturing of analytes through surface-grafted agents to localize them on plasmonic surfaces; (3) physically confining liquid analytes on non-wetting SERS-active surfaces and (4) confining gaseous analytes using porous materials over SERS hotspots; (5) synergizing conventional metal-based SERS platforms with functional materials such as graphene, semiconducting materials, and piezoelectric polymers. These approaches can be integrated with engineered hotspots as a multifaceted strategy to further boost SERS sensitivities that are unachievable using hotspot engineering alone. Finally, we highlight current challenges in this research area and suggest new research directions towards efficient SERS designs critical for real-world applications.
关键词： non-wetting surfaces,porous materials,Surface-enhanced Raman scattering,SERS,plasmonic surfaces,chemical coupling,hotspot engineering,semiconductors,piezoelectric polymers,analyte manipulation,hybrid materials,graphene
更新于2025-09-04 15:30:14
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Tetrathiafulvalene Scaffolds Based Sensitizer on Hierarchical Porous TiO <sub/>2</sub> : Efficient Light Harvesting Material for Hydrogen Production
摘要： In this work, a photochemical device that contains thioalkyl substituted tetrathiafulvalene dyes and hierarchical porous TiO2, has been designed and successfully employed in visible light-driven hydrogen production. The design strategy boost up the desirable photophysical properties of the catalysts and well supported from the optical, electrochemical and computational studies. The introduction of thioalkyl substituted tetrathiafulvalene dyes as light harvesting sensitizers onto the porous TiO2 triggers unprecedented high rate of hydrogen evolution. This study focuses on the role of thiafulvalene scaffold which can promote ultrafast interfacial electron injection from excited state dye into the hierarchical porous TiO2 conduction band. The purposeful construction of this integrated composite G3T3 (dye content 1.0 μmol in 10 mg Pt-TiO2 composite) significantly increases the hydrogen production rate of 24560 μmol.h-1g-1 cat with high apparent quantum yield (AQY) ~ 41%. In the study, both sensitizers absorption onset extends up to 500 nm in solution and 600 nm on hierarchical porous TiO2. Density functional theory (DFT) in the present study described that the HOMO levels are delocalized on anthracene as well as tetrathiafulvalene donor units, and LUMO covers on to the carboxylate anchoring group in both dyes. This study unveiled first time that a tetrathiafulvalene scaffolds in porous TiO2 attributes to positive synergistic effects in hydrogen production.
关键词： Tetrathiafulvalene,Hydrogen Production,Photocatalysis,Hierarchical Porous TiO2,Visible Light
更新于2025-09-04 15:30:14
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Intrinsically Porous Dual-Responsive Polydiacetylenes Based on Tetrahedral Diacetylenes
摘要： The combinatorial functionalization in a single molecular framework by structural integration utilizing multiple functional materials to create prede?ned structural morphology and multistimuli-responsive smart materials has attracted intensive attention. Herein, we constructed intrinsically porous and dual-responsive supramolecule, TeDA, by introducing a photopolymerizable diacetylene template (10,12-pentacosadiynoic acid) to the sterically rigid tetrahedral tetraphenylmethane (TPM) core. The self-assembled monomeric TeDA is transformed into the covalently cross-linked blue-phase polydiacetylene (TePDA) by UV irradiation (UV 254 nm). The BET measurement and examination of SEM images con?rm the mesoporous characteristic for TeDA/PDA. Very interestingly, the blue-phase TePDA produces a naked-eye detectable colorimetric response to heat and VOCs (liquid and vapor phase). Most importantly, TePDA exhibits reversible thermochromism and excellent colorimetric response to chloroform vapors. To signify the structural in?uence of TPM on material properties, we also studied non-TPM derivatives. The TeDA/PDA integrated system demonstrates potential applications in developing multistimuli-responsive sensors.
关键词： dual-responsive,porous,thermochromism,VOCs detection,colorimetric response,polydiacetylenes,tetrahedral diacetylenes
更新于2025-09-04 15:30:14