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- 实验方案
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Photo-Sensitive Pb5S2I6 Crystal Incorporated Polydopamine Biointerface Coated on Nanoporous TiO2 as an Efficient Signal-on Photoelectrochemical Bioassay for Ultrasensitive Detection of Cr(VI) ions
摘要： An ultrasensitive Visible light-triggered photoelectrochemical (PEC) sensor was designed based on ideal photoactive lead sulfoiodide (Pb5S2I6) as low band gap crystal, which hydrothermally synthesized rapidly at low temperature (160°C) in hydrochloride acid media followed by its incorporation into polydopamine as reactive photo-biointerface, through a facile in situ electropolymerization method, coated on nanoporous TiO2 grown by anodization on Ti foil. The structure of as-prepared samples and their photoelectrochemical properties were fully characterized. This unique photo-sensitive Pb5S2I6 catalyst-based PEC bioassay was constructed for the detection of low-abundant Cr(VI) ion in real samples. Applying central composite design, individual and mutual interaction effects were evaluated to obtain optimized solution pH, applied potential and radiant light wavelength as operational factors influencing the PEC efficiency for Cr(VI) detection. At optimal condition, the proposed sensor due to effective suppress in electron–hole recombinations showed a very low detection limit of 3.0 nM, over a broad linear concentration range of 0.01 μM-80 μM in addition to high sensitivity versus 1.9 μA/μM Cr(VI). Proposed PEC sensor displayed high selectivity, reproducibility and stability as well as improved excitation conversion efficiency, which make it highly applicable using solar energy. The potential applicability of the designed sensor was evaluated in water, tomato juice and hair color.
关键词： Photoelectrochemical biosensor,Nanoporous TiO2,Cr(VI) ions,Visible light excitation.,Pb5S2I6 crystal
更新于2025-11-21 11:01:37
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On the role of micro-porosity in affecting the environmental stability of atomic/molecular layer deposited (ZnO) <sub/>a</sub> (Zn–O–C <sub/>6</sub> H <sub/>4</sub> –O) <sub/>b</sub> films
摘要： Atomic/molecular layer deposited (ALD/MLD) inorganic–organic thin films form a novel class of materials with tunable properties. In selected cases, hybrid materials are reported to show environmental instability, specifically towards moisture. In this article, we focus on zinc oxide/zincone multi-layers with the theoretical formula of (ZnO)a(Zn–O–C6H4–O)b. We show by means of ellipsometric porosimetry that micro-porosity in the range of 0.42 and 2 nm in the pristine zincone layer is responsible for its environmental degradation. During degradation, it is found that a relative micro-porosity content of 1.2 ± 0.1 vol% in the pristine zincone films evolves into micro-mesoporosity with a relative content of 39 ± 1 vol%. We also show that the micro-porosity in the zincone layer can be gradually suppressed when few cycles (a = 1–10) of ZnO are introduced. The resulting (ZnO)a(Zn–O–C6H4–O)b = 1 periodic multilayer is an environmentally stable film with a = 10. It is found that the suppressed micro-porosity is due to the development of continuous ZnO layers with a ≥ 10.
更新于2025-11-21 11:01:37
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Tessellation of Chiral-Nematic Cellulose Nanocrystal Films by Microtemplating
摘要： In biological architectures, material properties are optimized by the hierarchical structuring of components with a multiscaled order, from the nano- to the macroscales. Such designs enable, for instance, programmed yield points that maximize toughness. However, research efforts in biomimetic materials have focused on the assembly of nano- or macrostructures individually. In this study, high strength cellulose nanocrystals (CNCs), assembled into chiral-nematically ordered structures, are tiled into a higher level, macro-sized, architecture by topographical templating. As templates, two meshed architectures with distinct feature sizes are evaluated, and the optomechanical properties of the resulting films are compared to featureless, flat, CNC films. Controlling capillary stresses arising during CNC assembly is shown to enable control over the orientation of the chiral-nematic director across the topography of the template. Tuning the specific reflections and multiscaled fracture propagation is demonstrated for the microtemplated CNC films. The latter phenomenon contributed to enhancing the toughness of the material through a high tortuosity of fracture propagation in all (x, y, z) directions. The presented findings are expected to pave the way towards the incorporation of current research in cellular metamaterials with the research focusing on the generation of nanoscaled biomimetic constructs.
关键词： tessellation,conformability,biomimetic,hierarchical,cellulose nanocrystals
更新于2025-11-21 11:01:37
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Spectral analysis and temperature measurement during flash sintering under AC electric field
摘要： In-situ diffraction experiments were used to study the change in peak profiles of 8YSZ during conventional sintering and flash sintering under AC electric field. Using calibration from a conventionally heated standard, the lattice expansion of 8YSZ under flash conditions was correlated to actual specimen temperature, indicating temperature comparable to that required for conventional sintering. At higher current densities, a temperature rise greater than 2000 °C was reached, which resulted in abnormal grain growth and temperature instability. Microstructural analysis demonstrated that finer grain size can be achieved by limiting the current in order to avoid high specimen temperatures. Experiments varying the thickness of the green compact resulted in higher heat loss due to thermal conduction and corresponding reduction in final density. A replacement to the blackbody radiation model was successfully used to fit the data and explain all effects based on Joule heating as well as provide a flash sintering processing map incorporating furnace temperature, power dissipation, and sample geometry.
关键词： 8YSZ,processing map,fast firing,flash sintering,energy dispersive diffraction
更新于2025-11-21 11:01:37
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Spectrophotometric Characterization of Thin Copper and Gold Films Prepared by Electron Beam Evaporation: Thickness Dependence of the Drude Damping Parameter
摘要： Copper and gold films with thicknesses between approximately 10 and 60 nm have been prepared by electron beam evaporation and characterized by spectrophotometry from the near infrared up to the near ultraviolet spectral regions. From near normal incidence transmission and reflection spectra, dispersion of optical constants have been determined by means of spectra fits utilizing a merger of the Drude model and the beta-distributed oscillator model. All spectra could be fitted in the full spectral region with a total of seven dispersion parameters. The obtained Drude damping parameters shows a clear trend to increase with decreasing film thickness. This behavior is discussed in the context of additional non-optical characterization results and turned out to be consistent with a simple mean-free path theory.
关键词： optical constants,gold,copper,ultrathin metal films,thickness dependence
更新于2025-11-21 11:01:37
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Effect of electron beam irradiation on structure, morphology, and optical properties of PVDF-HFP/PEO blend polymer electrolyte films
摘要： The effect of 8 MeV energy electron beam (EB) on poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/poly-ethylene oxide (PEO) (@ w/w 90:10, PHP10) polymer blend films have been prepared and studied. The change in structure, morphology, and optical properties at 40, 80, and 120 kGy EB doses were investigated. The effect of the radiation process may responsible to occurs the degradation (chain scission) and chain link (cross linking) which are confirmed by the FT-IR analysis. The band at 1401 cm?1 corresponding to the –CH2– bending or scission mode have shifted to 1397 cm?1 after 120 kGy EB dose is due to the intermolecular interaction and the changes of the macromolecular chain by breaking of bonds with increased EB dose was observed. The XRD pattern shows decreased in the crystallinity from 60.03 to 23.42% and increased amorphousity for 120 kGy EB dose the and the surface morphology was drastically changed by decreasing the size of spherulites upon increased EB dose. The increase in optical absorption and the shifting of wavelength toward a higher end (red shift) was observed after the irradiation. The energy band gaps (Eg), and Urbach energy were estimated and they are found to be decreased, but the number of carbon atoms in a cluster of was increased with increased EB dose. The obtained results notice that the physical properties of polymer blend electrolytes can be improved by EB irradiation to use in different potential applications.
关键词： Polymer electrolyte,FESEM,UV–visible spectroscopy,Structural analysis,Electron beam irradiation
更新于2025-11-21 11:01:37
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Structural, electrical and dielectric studies on (1???x)MgTiO3???x Ba0.5Sr0.5TiO3 composite ceramics for type-II capacitor applications
摘要： The structural, microstructural, electrical and broadband dielectric properties of (1 ? x)MgTiO3 ? xBa0.5Sr0.5TiO3 (for x = 0.1 to 0.5) composite ceramics has been reported. Conventional solid state reaction method is followed for preparation of the powder and maximum densification is optimized at different sintering temperatures (1250 to 1400 °C). The structural studies revealed presence of both MTO and BST phases independently. The cryogenic dielectric response was studied over a broadband frequency range. The composite ceramics have exhibited diffused transition as a typical signature of relaxor ferroelectrics with temperature. Modified Curie–Weiss law is implemented and calculated the diffuseness constant to probe the relaxor behavior of the ceramics. The Impedance analysis in complex plane showed non-Debye type relaxation behavior. Correlated barrier hopping mechanism is found to be responsible for conduction process at higher frequency region in AC-conductivity analysis. The thermal stability of capacitance over the temperature range of (RT) ? 30 to + 85 °C determined and found to be ~ ? 54%. The 0.7 MTO—0.3 BST ceramic composite sintered at a temperature (Ts) of 1350 °C is optimized as the best composition with the highest values of relative density (~ 97%), high dielectric permittivity εr ~ 57 and quality factor, Q × f0 = 19,30 GHz at 4.16 GHz. The obtained properties of the composite ceramics is promising for type -II capacitors in integrated circuits of de-couplers and filters.
更新于2025-11-21 11:01:37
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Influence of Non-Toxic Magnetic Cellulose Nanofibers on Chitosan based Edible Nanocoating: A Candidate for Improved Mechanical, Thermal, Optical, and Texture Properties
摘要： The present work demonstrates the formulation of cellulose nanofiber (CNF) or magnetic cellulose nanofiber (mgCNF) dispersed chitosan based edible nanocoating with superior mechanical, thermal, optical and texture properties. The fabrication of mgCNF is successfully achieved through single-step co-precipitation route, where iron particles get adsorbed onto CNF. The thermal stability of mgCNF is improved considerably, where ~17% reduction in weight is observed, whereas CNF degrades completely under identical conditions. TGA analysis shows that there is an improvement in thermal stability for both CNF and mgCNF reinforced CS nanocoatings, where mgCNF provides more heat dimensional stability than CNF dispersed CS nanocoatings. Further, the edible nanocoatings are stable even at the temperature of heat treatment such as food sterilization. The mechanical property of the mgCNF dispersed chitosan (CS) shows remarkable improvement in tensile strength (57.86±14 MPa) and Young’s modulus (2348.52±276 MPa) compared to neat CS (6.27±0.7 MPa and 462.36±64 MPa, respectively). To recognize the developed materials as safe as food, the quantification of iron is made by using ICP-MS technique. It is noteworthy to mention that mgCNF coated CS help in improving the texture of cut pineapples in comparison with uncoated pineapple slices at ambient condition.
关键词： chitosan,magnetic cellulose nanofibers,cellulose nanofiber,edible nanocoating,packaging property
更新于2025-11-21 11:01:37
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Rational design of manganese cobalt phosphide with yolk‐shell structure for overall water splitting
摘要： The development of low cost, earth-abundant and efficient catalysts for overall water splitting, involving hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), attracts tremendous attention in recent years. Herein, this work reports the preparation of Mn-Co phosphide (Mn-Co-P) bifunctional catalysts with a yolk-shell structure by a facile hydrothermal route. The as-prepared catalysts exhibit excellent catalytic activity with low overpotentials of 66 mV at 10 mA cm-2 for HER and 355 mV at 50 mA cm-2 for OER in 1 M KOH, along with outstanding stability. More importantly, the cell voltage of 1.74 V can achieve the current density of 10 mA cm-2 when assembled as an electrolyzer for overall water splitting. Such superior performance makes the Mn-Co-P being a promising candidate to replace Pt-based noble metal catalysts for electrocatalytic applications.
关键词： yolk-shell structure,electrochemistry,Mn-Co phosphide,overall water splitting,bifunctional catalyst
更新于2025-11-21 11:01:37
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Effect of CoFe2O4 weight fraction on multiferroic and magnetoelectric properties of (1 ? x)Ba0.85Ca0.15Zr0.1Ti0.9O3?????xCoFe2O4 particulate composites
摘要： Different compositions of the composite lead-free multiferroic magnetoelectric systems are fabricated by employing piezoelectric Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) and magnetostrictive CoFe2O4 (CFO) by varying the CFO weight fraction. The magnetic, dielectric, ferroelectric and magnetoelectric (ME) properties of the system are analyzed and found to be varying with the ferrite concentration. Even though the composite systems exhibit high magnetocapacitance (MC) properties (~ 35%), the possible stray contributions from magnetoresistance and magnetostriction make it unreliable for the quantitative determination of ME coupling coefficient (MECC). Therefore, a dynamic method is chosen for the measurement of magnetoelectric coupling. All the compositions have shown fairly good ME coupling. It is found that the ME coupling increases with ferrite fraction and the highest ME coupling of 14.8 mV/(cm Oe) is observed for 0.6BCZT–0.4CFO composite. It is also observed that the ME voltage increases linearly with the ac modulating field with a voltage generation of 1.25 V/cm (for x = 0.4) for a small ac modulating field of 100 Oe. This high sensitivity and linear response of ME coupling to the ac magnetic fields offer the possibility of employing these particulate composites for a wide range of applications from magnetic field sensors to energy harvesters.
更新于2025-11-21 11:01:37