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Synthesis, characterization and electrochemical properties of Cadmium sulfide -Reduced Graphene Oxide nanocomposites
摘要： Nowadays, research interest is speedily growing for fabrication of semiconductor metal sulfide nanoparticles. Proper optimization of process variables for the synthesis process can ensure tunable morphologies and distinct characteristics. Appropriate synthesis strategy can alter their electrical, optical and catalytic properties significantly. A simple, one step, the hydrothermal approach has been undertaken to prepare CdS/rGO nanocomposite here. This technique ensures fabrication of graphene-based nanocomposites with outstanding electro-catalytic characteristics using a facile route. The structural, morphological and the electrochemical properties of the synthesized sample were observed. Surface morphological features together with its phase was identified using FESEM, TEM, and XRD analysis. The crystalline phase of the synthesized sample was confirmed from the X-ray diffraction pattern. Surface functional groups of the synthesized sample were analyzed using the FTIR and FT-Raman analysis. The optical characterization of the CdS and CdS/rGO nanocomposite were examined. The FESEM and TEM images were used to illustrate the surface morphology and particle size of the CdS and CdS/rGO nanocomposite. The elemental composition of the synthesized sample was evaluated using EDAX analysis. In this research, the values for dielectric loss, dielectric constant, and resistivity and AC conductivity of the synthesized samples were determined. Thus, the overall electrochemical features of the prepared sample were evaluated. The results elucidated here showed that the synthesized sample can be used as potential electrode materials for supercapacitor ensuring high energy.
关键词： CdS/rGO,nanocomposite,Graphene,electrochemical studies
更新于2025-09-23 15:19:57
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A Novel Perylene Derivative/Luminol Nanocomposite as Strong Electrochemiluminescence Emitter for Construction of Ultrasensitive MicroRNA Biosensor
摘要： In this work, an electrochemiluminescent (ECL) biosensor was constructed on the basis of amino-modified 3,4,9,10-perylenete-tracarboxylic dianhydride/luminol (PTC-NH2/Lu) nanocomposite as emitter and bipedal DNA walker signal amplification strategy for ultrasensitive detection of microRNA-21 (miRNA-21). The PTC-NH2/Lu nanocomposite was prepared as signal tag via π-π stacking molecular assembly, in which amino-modified 3,4,9,10-perylenete-tracarboxylic dianhydride (PTC-NH2) as a novel co-reaction accelerator significantly enhanced the ECL emission of luminol-H2O2 system. Moreover, target miRNA-21 triggered bipedal DNA walker was powered by toehold-mediated strand displacement reaction (TSDR) for signal amplification. Consequently, the proposed ECL biosensor achieved ultrasensitive detection of miRNA-21 with linear range from 100 aM to 100 pM and limit of detection 33 aM. Simultaneously, the biosensor was also successfully applied to detect target miRNA-21 in lysates from human cancer cells. As a result, this work constructed a new signal amplification platform, exhibiting great application potential in biomedical analysis and early clinical diagnostics.
关键词： PTC-NH2/Lu nanocomposite,electrochemiluminescence,co-reaction accelerator,π-π stacking molecular assembly,bipedal DNA walker
更新于2025-09-23 15:19:57
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The technique of visualization and evaluation of the emission site distribution for large area field emitters
摘要： This paper presents a method for online treatment of the distribution pattern of emission sites on the emitter surface, combined with a multichannel registration and processing system of the IVC. Using computerized field emission projector we have studied nanocomposite emitter based on carbon nanotubes "Taunit M" and polystyrene. The distribution pattern of emission sites over the brightness level was obtained as well as the emission area of the sample was determined. Time dependences of the current level, the total brightness and the emission area were registered.
关键词： field emission,emission area,emission sites distribution,carbon nanotubes,nanocomposite emitter
更新于2025-09-23 15:19:57
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Ferroelectric mesocrystalline BaTiO <sub/>3</sub> /BaBi <sub/>4</sub> Ti <sub/>4</sub> O <sub/>15</sub> nanocomposite: formation mechanism, nanostructure, and anomalous ferroelectric response
摘要： Ferroelectric mesocrystalline nanocomposites are promising materials for the enhancement of ferroelectricity via lattice strain engineering due to their high density of heteroepitaxial interfaces. In the present study, a ferroelectric mesocrystalline BaTiO3/BaBi4Ti4O15 (BT/BBT) nanocomposite was synthesized using the layered titanate H1.07Ti1.73O4 via a facile two-step topochemical process. The BT/BBT nanocomposite is constructed from well-aligned BT and BBT nanocrystals oriented along the [110] and [11?1] crystal-axis directions, respectively. Lattice strain is introduced into the nanocomposite through the formation of a BT/BBT heteroepitaxial interface, which results in a greatly elevated Curie temperature for BBT in the range of 400 °C to 700 °C and an improved piezoelectric response with d*33 = 130 pm V?1. In addition, the BT/BBT nanocomposite is stable up to a high temperature of 1100 °C; therefore, mesocrystalline ceramics can be fabricated as high-performance ferroelectric materials.
关键词： piezoelectric response,nanocomposite,ferroelectric,mesocrystalline,BaBi4Ti4O15,BaTiO3,Curie temperature,lattice strain
更新于2025-09-19 17:15:36
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Thermoelectric Properties of (100) Oriented Silicon and Nickel Silicide Nanocomposite Films Grown on Si on Insulator and Si on Quartz Glass Substrates
摘要： We have grown (100) oriented composite films of Si and Ni silicide nanocrystals (Ni–Si NC film) on substrates of Si on insulator (SOI) and Si on quartz glass (SOQ). Owing to improvement of carrier transport properties and reduction of the thermal conductivity in the oriented films, they have higher dimensionless figures of merit, ZT of 0.22–0.42 for p-type Ni–Si NC film and 0.08–0.13 for n-type Ni–Si NC film than that of bulk Si (ZT < 0.01) at 30°C. The ZT values of p-type and n-type Ni–Si NC films were increased to 0.65 and 0.40 at 500°C, respectively.
关键词： silicon based thermoelectric materials,nanocomposite films,nickel silicide nanocrystals,silicon nanostructures,phonon scattering
更新于2025-09-19 17:15:36
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Reduced graphene oxide@ceria nanocomposite-coated polymer microspheres as a highly active photocatalyst
摘要： Herein we report a facile two-step synthetic strategy for fabricating the ternary polystyrene/reduced graphene oxide/ceria (PS/RGO@CeO2) nanocomposite particles for the first time through the self-assembly of the RGO on the surface of PS microsphere (PS/RGO) and then the attachment of CeO2 nanoparticles (NPs) onto the as-prepared PS/RGO nanocomposite particles. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis have been employed to characterize the morphology and composition of the as-prepared samples. The size and mass loading of resulting CeO2 NPs on the PS/RGO nanocomposite particles are easily tunable. Furthermore, the photocatalytic performance of as-prepared ternary nanocomposite particles towards the degradation of methylene blue is investigated. Notably, the PS/RGO@CeO2 nanocomposite particles have high photocatalytic activity due to the synergistic effect between the CeO2 NPs and RGO in such a unique structure, and moreover, they also exhibit high stability in a recyclable manner. Therefore, it can be expected that our ternary nanocomposite particles are an attractive photocatalyst candidate for various photocatalytic applications.
关键词： polystyrene microsphere,ceria nanoparticle,reduced graphene oxide,nanocomposite particle,catalysis
更新于2025-09-19 17:15:36
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One Step Deposition of PEDOT–PSS on ALD Protected Silicon Nanowires: Toward Ultrarobust Aqueous Microsupercapacitors
摘要： Herein, we propose a fast and simple deposition method of a highly robust pseudocapacitive material based on a straightforward drop-cast of a commercial PEDOT:PSS solution onto 3 nm alumina-coated silicon nanowires. The composite material produced (PPSS-A@SiNWs) displays remarkable capacitive behavior with a specific capacitance of 3.4 mF·cm?2 at a current density of 2 A·g?1 in aqueous Na2SO4 electrolyte. Moreover micro-supercapacitor (MSC) devices based on this material exhibits outstanding lifetime capacity retaining 95% of its initial capacitance after more than 500 000 cycles at a current density of 0.5 A·g?1, a specification which exceeds by far most of the stability of conducting polymers previously reported in the literature. In term of pure energy storage performances, the system is able to reach excellent specific energy and power values of 8.2 mJ·cm?2 and of 4.1 mW·cm?2, respectively, at a high current density of 2 A·g?1. Results are systematically compared to both the state-of-the-art silicon based aqueous on-chip supercapacitors and to that of the pristine alumina-coated silicon nanowires (A@SiNWs) to highlight the contribution of the conductive PEDOT:PSS polymer (PPSS in this study). Hence, the aforementioned one-step deposition represents a simple, cheap and scalable method to thoroughly increase the cycling stability of a well-known conductive polymer, PEDOT?PSS, while drastically increasing the electrochemical performances of an existing technology, the Si NW-based MSCs using aqueous electrolytes.
关键词： microsupercapacitors,silicon nanowires,conductive polymer,aqueous electrolyte,ultrarobust,nanocomposite
更新于2025-09-19 17:15:36
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A novel nanocomposite of mesoporous silica supported Ni nanocrystals modified by ceria clusters with extremely high light-to-fuel efficiency for UV-Vis-IR light-driven CO2 reduction
摘要： A novel nanocomposite of mesoporous silica supported Ni nanocrystals modified by ceria clusters was synthesized by a facile approach. The nanocomposite exhibits high photothermocatalytic activity for CO2 reduction by CH4 to produce CO and H2 (CRM) under focused UV-visible-infrared illumination without using any additional heater. Extremely high production rates of H2 and CO (33.42 and 41.53 mmol min-1 g-1) as well as extraordinarily high light-to-fuel efficiency of 27.4% are achieved. The nanocomposite also has efficient CRM photothermocatalytic activity even under focused λ > 690 nm visible-infrared illumination. It is discovered that the ceria cluster modification of Ni nanocrystals markedly improves the photothermocatalytic activity and durability. The excellent CRM photothermocatalytic activity is ascribed to highly effective light-driven thermocatalytic CRM due to the photothermal conversion across the entire solar spectra and good CRM thermocatalytic activity of the nanocomposite. A novel photoactivation is discovered to markedly enhance the light-driven thermocatalytic activity. Based on the experimental evidences of TG-MS, XRD, TEM, in-situ FTIR, Raman, and isotope labelling together with the DFT calculations, we reveal the origin of the markedly enhanced phtotothermocatalytic activity and durability as well as the novel photoactivation. Oxygen of ceria cluster in the nanocomposite participates in CRM on Ni nanocrystals, which markedly decreases the activation energies of the oxidation of C* and CH* species as CRM dominant steps. The focused illumination considerably reduces the activation energy of CRM on the nanocomposite, thus markedly enhancing the photothermocatalytic activity.
关键词： photothermocatalytic,CO2 reduction,photocatalytic,nanocomposite,light-to-fuel efficiency
更新于2025-09-19 17:15:36
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Photocatalytic decontamination of phenol and petrochemical wastewater through ZnO/TiO <sub/>2</sub> decorated on reduced graphene oxide nanocomposite: influential operating factors, mechanism, and electrical energy consumption
摘要： ZnO/TiO2 anchored on a reduced graphene oxide (rGO) ternary nanocomposite heterojunction was synthesized via the multi-step method including hydrothermal, solvothermal and sol–gel methods. XRD, Raman, FESEM, EDX, Dot Mapping EDS, BET, FTIR, UV-VIS, TGA, and EIS techniques were utilized for characterizing as-synthesized catalysts. The XRD and Raman data proved the formation of anatase phase TiO2 and wurtzite phase ZnO in the prepared samples. Further, the UV-Vis spectrum confirmed that the band gap value of ZnO/TiO2 diminished on introduction of graphene oxide. Photocatalytic performance of the fabricated catalysts was investigated by decontamination of phenol in aqueous solutions. The effect of different operational factors such as pH, catalyst dosage, phenol concentration, and light illumination was investigated to find the optimum decontamination conditions. According to the results, complete degradation of phenol was achieved at pH = 4, catalyst dosage of 0.6 g L?1, light intensity of 150 W, and phenol initial concentration of 60 ppm at 160 min under visible light illumination. With the addition of graphene oxide to the composite, a significant increase was detected in the photocatalytic performance due to the higher available surface area and lower electron/hole recombination rate. In addition, the scavenging experiments revealed that the ?OH is responsible for the degradation of phenol during the reaction. The degradation mechanism, economic performance, mineralization, and recyclability were also investigated. Kinetic studies confirmed that photocatalytic degradation process followed the pseudo-first-order kinetic model. A case of real wastewater treatment was used to examine the performance of the catalyst for real case studies.
关键词： Phenol degradation,Nanocomposite,Wastewater treatment,Photocatalysis,ZnO/TiO2,Reduced graphene oxide
更新于2025-09-19 17:15:36
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Enhanced dielectric property and energy density in poly(vinylidene fluoride-chlorotrifluoroethylene) nanocomposite incorporated with graphene functionalized with hyperbranched polyethylene- <i>graft</i> -poly(trifluoroethyl methacrylate) copolymer
摘要： Polymer film capacitors are attractive as promising candidates for potential applications in compact and efficient electric power systems. The development of a method for producing a polymer nanocomposite with enhanced dielectric property and a high energy density is a fundamental solution for electric storage in a film capacitor. In this work, a hyperbranched polyethylene-graft-poly(trifluoroethyl methacrylate) (HBPE-g-PTFEMA) copolymer was synthesized to exfoliate and functionalize graphene from natural graphite in chloroform on the basis of the CH–π non-covalent stacking between the HBPE-g-PTFEMA stabilizer and graphene. Examination of the morphologies by transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirmed that the resulting graphene had a lateral size of 0.2–0.6 μm and a thickness of around 4 layers. The presence of peaks due to F in the X-ray photoelectron spectroscopy (XPS) spectra of graphene indicates that the fluorinated copolymer was attached to the surface of nanosheets. Few-layer graphene was introduced into a poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE)) matrix via simple solution casting. The relative content of the electroactive phase in the nanocomposite film increased because the phase transition from the α- to the β-phase was induced by the addition of graphene. The dielectric constant increased to 24.8 with a low dielectric loss of 0.06 at 100 Hz for a 0.8 vol% nanocomposite, and a released energy density of 4.6 J cm?3 with a charge–discharge efficiency of 62% at 250 MV m?1 was achieved with a 0.1 vol% nanocomposite, which was attributed to the combination of the large content of the electroactive phase and interfacial polarization. This strategy based on a nanocomposite with graphene exfoliated by a fluoropolymer sheds light on the mechanism of interfacial polarization and exhibits commendable prospects for applications in flexible film capacitors.
关键词： graphene,poly(vinylidene fluoride-chlorotrifluoroethylene),hyperbranched copolymer,nanocomposite,energy density,dielectric property
更新于2025-09-19 17:15:36