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Graphene role in improved solar photocatalytic performance of TiO2-RGO nanocomposite
摘要： TiO2-RGO (TG) nanocomposite applied as photocatalysts have been synthesized via a facile low-temperature wet chemistry process, during which the reduction of graphene oxide (RGO) and the growth of titanium dioxide (TiO2) nanoparticles on the RGO nanosheets are achieved simultaneously. RGO role in TG nanocomposites as photocatalysts were analyzed in methylene blue photocatalytic degradation under UV and solar irradiation. The TG nanocomposites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The photocatalytic efficiency of the TG-30 sample under UV and TG-45 solar irradiation was ～7 and ～5 times that of pristine TiO2, respectively. The enhancement of the photocatalytic activity with UV irradiation in TG was attributed to the high separation efficiency of photoinduced electron–hole pairs, while the enhancement of photocatalytic activity with solar irradiation in the TG was attributed to RGO role, acted as a photosensitizer and a charges separator, simultaneously.
关键词： semiconductors,Solar photocatalysis,photosensitizer,composite materials,charger separator,recombination and trapping
更新于2025-09-23 15:22:29
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Tunable luminescence and transmittance nature of CdS:PMMA nanocomposites for optoelectronic applications
摘要： Optical and energy storage materials based on semiconductors are of great interest today. The present report explains the semiconductor nanocomposite centered on highly transparent Poly(methyl methacrylate) (PMMA) matrix and Cadmium Sulphide (CdS) nano particles. The solid ?lms of CdS:PMMA composite was prepared using simple and cost e?ective solution casting technique. The surface morphology and the presence of CdS particles in PMMA matrix was analysed using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectra (EDX). The size of the particles was analysed using Atomic Force Microscopy (AFM) and Transmission Electron Microscope (TEM) and they revealed the presence of nano sized particles. The narrow size distribution of particles was identi?ed from TEM and AFM analysis. The transmittance of the CdS:PMMA nanocomposite solid ?lms was found to be above 90%. The blue and green emission of CdS:PMMA nanocomposite solid ?lms were observed from Photoluminescence (PL) spectra.
关键词： Composite materials,Polymeric composite,Luminescence,Green emission,Particle distribution,Transmittance
更新于2025-09-23 15:21:01
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Controlled synthesis of AgNPs@ZIF-8 composite: Efficient heterogeneous photocatalyst for degradation of methylene blue and congo red
摘要： Photocatalytic degradation of organic dyes using novel metal based composite materials is one of the most intriguing and sustainable ways to reduce water pollution. Herein, facile synthesis of AgNPs@ZIF-8 via in situ generation of AgNPs and ZIF-8 (Zeolitic Imidazolate Framework) was demonstrated, and composites with different Ag contents (abbreviated as SZ, SZ1, SZ2 SZ3) were well characterized by powder X-ray diffraction (PXRD) pattern, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FT-IR) spectroscopy. Encapsulation/decoration of AgNPs (particle size: 96 nm in SZ and 17.32 ± 2.35 nm in SZ1 to SZ3) in ZIF-8 matrix has been ensured by TEM and EDX analysis. Brunauer-Emmett-Teller (BET) adsorption-desorption studies indicate that the surface area of SZ (982 m2 g?1) is less than those of SZ1 to SZ3 (due to the encapsulation of large amount of Ag nanoparticles in SZ). The synthesized composites are thermally stable up to 400 °C in air and nitrogen atmosphere. AgNPs@ZIF-8 exhibited excellent photocatalytic efficiency to degrade organic dyes compared to ZIF-8 due to its large surface area, highly porous and unique synergistic properties. SZ2 degrades off 97.25 % methylene blue (MB) and 100 % congo red (CR) at pH ≥ 7. Further, degraded fragments were analysed by GC–MS and plausible degradation mechanism was discussed.
关键词： Silver nanoparticles,Organic pollutants,Photocatalyst,Heterogeneous catalysis,Composite materials
更新于2025-09-23 15:21:01
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Type-II heterojunction constructed by Ag2S-coupled ZnO microspheres with visible light-responsive antibacterial activity
摘要： ZnO nanorods-assembled microspheres were photosensitized with a layer of low bandgap Ag2S nanoparticles on the branched nanorods to get a type-II core/shell heterojunction (ZnO@Ag2S). The heterojunction with unique band configuration exhibited better visible light-responsive antibacterial activity than pure ZnO, which is attributed to the inhibition of photocarrier recombination and efficient charge separation and transfer. Scavenger test confirmed that the photoinactivation of bacteria was directed by the (cid:1) radicals and photogenerated holes. The growth of Gram-negative bacteria was more effectively restrained by ZnO@Ag2S than that of Gram-positive bacteria and fungi because of structural difference of cell walls.
关键词： ZnO@Ag2S,Composite materials,Mechanism,Semiconductors,Photocatalytic activity
更新于2025-09-23 15:21:01
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Thermophysical Properties of Silicon-Carbide-Based Ceramic Composite Materials Obtained by Spark Plasma Sintering (SPS)
摘要： The factors influencing the thermal conductivity of SiC-based ceramic composite materials obtained by the spark plasma sintering technology with relative density 99% and B4C, AlN, Si3N4, Y2O3, Al2O3, and HfB2 as additives are examined. The thermophysical properties were determined in the temperature range 20 – 1300°C: specific heat, thermal diffusivity, and thermal conductivity of composites. The thermal diffusivity and specific heat were measured by the laser-spark method. The measurements of specific heat are supplemented by measurements performed with a DSC and adiabatic calorimeter. The thermal conductivity is calculated using data on the thermal diffusivity, specific heat, and density.
关键词： laser flash method,specific heat,adiabatic calorimeter,thermal conductivity,ceramic composite materials,thermal diffusivity,thermophysical properties,differential scanning calorimetry (DSC)
更新于2025-09-19 17:15:36
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Ultraviolet Digital Image Correlation for Molten Thermoplastic Composites under Finite Strain
摘要： The thermostamping process used to fabricate thermoplastic prepreg composites is widely studied due to its use in several applications in the automotive and aerospace industries. In recent years, different constitutive mechanical models and new numerical techniques have been proposed to simulate this process. However, from an experimental point of view, no substantial progress has been recorded on the experimental methods used for the characterisation of thermostamped thermoplastic prepreg composites. Moreover, there is currently no experimental protocol to visualize or analyse deformation fields at temperatures above the melting point of a material during the characterisation process. The knowledge of these fields allows precision modelling of the mechanical behaviour of this type of material. Therefore, the aim of this paper is to propose a new experimental protocol that uses a digital image correlation method, which faces constraints such as light reflections on either the yarns or the molten thermoplastic matrix. The proposed solution uses an ultraviolet light source and a photoluminescent powder to make the speckle pattern. This approach avoids any visible reflections, since the sample itself is the visible light source.
关键词： Thermoplastic composite materials,Shear field measurement,Ultraviolet DIC,Bias extension test
更新于2025-09-19 17:15:36
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All-Waste Hybrid Composites with Waste Silicon Photovoltaic Module
摘要： Nowadays, global warming, energy issues and environmental concern have forced energy production stakeholders to find new low carbon solutions. Photovoltaic technologies as renewable energy resources represent a competitive way for the transition from conventional fossil fuels towards a renewable energy economy. The highest renewable energy systems (RES) market share is based on silicon photovoltaic (Si-PV). The installed RES have rapidly increased over the last two decades, but, after the end of their service life, they will be disposed of. Therefore, the constant increase of the installed RES has attracted the global concern due to their impact on the environment and, most of all, due to the content of their valuable resources. However, the rational management of RES waste has not been addressed so far. The paper represents an extension of a previous work focused on Si-PV recycling by developing all waste hybrid composites. The extension research conducted in this paper is related to the influence of Si-PV characteristics on the mechanical performances and water stability of the hybrid composites. All waste hybrid composites developed by embedding different Si-PV grain sizes were tested before and after water immersion in terms of mechanical strength, interfacial adhesion, crystallinity and morphology by scanning electron microscopy (SEM) analyses. The results revealed the better performance of such Si-PV composites compared to that of sieved composites even after long term water immersion. Therefore, high-content Si-PV hybrid composites could be developed without Si-PV powder sieving. Further on, all waste hybrid composites could be used as paving slabs, protective barriers for outdoor applications.
关键词： silicon photovoltaic module,water stability,all waste hybrid composite materials,interfacial adhesion,recycling,mechanical properties
更新于2025-09-16 10:30:52
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Roll-to-roll printed stable and thickness-independent ZnO:PEI composite electron transport layer for inverted organic solar cells
摘要： Large-scale roll-to-roll (R2R) micro-gravure printing is one of the most e?ective fabrication techniques to achieve the commercialization of organic solar cells (OSCs). In the high-performance OSC devices, the electron transport layer (ETL) plays an important role. In this paper, a composite ink of ZnO and polyethylenimine (PEI) was developed to fabricate large-area ETL for the inverted OSCs through R2R micro-gravure printing. It was found that the modi?cation of ZnO nanoparticles by PEI e?ectively improved ink stability and enhanced the mechanical property. Using R2R micro-gravure printing, the thickness and coverage of the ZnO: PEI ?lms were well regulated through changing the printing roller speed and web speed. Consequently, a high-power conversion e?ciency around 6% was obtained for the ?exible PTB7-Th: PC71BM device with the thickness of R2R printed ZnO: PEI layer up to 120 nm, demonstrating the high printability of this ZnO: PEI composite material for the use in printed ?exible OSCs as the interface layer.
关键词： Organic solar cells,Roll-to-roll printing,Thickness-independent,Long-term stability,ZnO: PEI composite materials
更新于2025-09-16 10:30:52
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Studying Stability of CFRP Composites to Low-Energy Impact Damage by Laser Vibrometry
摘要： Nondestructive quality control of small-thickness composites is an important scientific and technical problem due to significant damage inflicted on materials even with minor impact loads. The stability of a 1-mm–thick CFRP composite to impact damage with an energy of up to 10 J has been investigated. Special attention has been paid to the analysis of the “visible” area of defects formed as a result of successive striking with increasing and decreasing energy in the range from 1 to 5 J. The area of defect indications was estimated by analyzing the images of vibrations at the surface of the composite produced by its acoustic stimulation and laser vibroscanning.
关键词： scanning laser vibrometry,nondestructive testing,impact damage,CFRP composite materials
更新于2025-09-12 10:27:22
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MoC/MnO composite materials as high efficient and stable counter electrode catalysts for dye-sensitized solar cells
摘要： MoC/MnO composite materials have been easily synthesized via a two-step hydrothermal and one-step carbonization method and used as counter electrode catalysts in DSSCs for the first time. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). And their electrocatalytic properties were also thoroughly studied by electrochemical impedance spectroscopy (EIS), Tafel polarization and so on. It is found that the electrocatalytic properties of the MoC/MnO CEs can be greatly enhanced. After optimizing the molar ratio of MoO3 precursor and KMnO4, the as-obtained MoC/MnO-0.25 CE has superior electrocatalytic ability, low charge transfer resistance and high incident photon-to-current conversion efficiency (IPCE). And the power conversion efficiency of the DSSC based on the MoC/MnO-0.25 CE is up to 8.00%, better than that of the DSSC used standard Pt CE (7.36%) in the same test environment, meanwhile the MoC/MnO-0.25 CE also has good electrochemical stability in the iodine-based electrolyte, which shows a promising candidate to replace Pt for DSSCs.
关键词： MoC/MnO composite materials,carbonization method,hydrothermal method,counter electrode catalysts,dye-sensitized solar cells
更新于2025-09-12 10:27:22