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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Effect of Catalysts on Hydrothermal Preparation of boron nitride nanostructures
摘要： Boron nitride (BN) has attracted intense interests due to its excellent thermal conductivity and electrical insulation, which make it a promising thermal interface material for electronic packaging. Conventionally, the BN nanostructures were made from high cost method, e.g. chemical vapor deposition (CVD), which was restricted by the extremely high reaction temperature as well as the expensive instruments. Herein, a facile hydrothermal method was presented, where the catalysts were used to tune the phase and morphologies of the BN products starting from the boron and nitrogen sources. With different catalysts, the phase of the products could be changed from the orthorhombic to cubic BN, and the morphology underwent an evolution from nanorods to nanoflowers. The results are of great significance for the large-scale fabrication of BN nanostructures in a low cost.
关键词： Nanoflowers,Hydrothermal synthesis,Morphology evolution,Nanorods,Boron nitride,Catalyst
更新于2025-09-10 09:29:36
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Two Highly Stable Luminescent Lead Phosphonates Based on Mixed Ligands: Highly Selective and Sensitive Sensing for Thymine Molecule and VO <sub/>3</sub><sup>–</sup> Anion
摘要： Two luminescent lead phosphonates with two-dimensional (2D) layer and three-dimensional (3D) framework structure, namely, Pb3[(L1)2(Hssc)(H2O)2] (1) and [Pb2(L2)0.5(bts)(H2O)2]·H2O (2) (H2L1 = O(CH2CH2)2NCH2PO3H2, H4L2 = H2PO3CH2NH(C2H4)2NHCH2PO3H2, H3ssc = 5-sulfosalicylic acid, NaH2bts = 5-sulfoisophthalic acid sodium) have been prepared via hydrothermal techniques. The two compounds not only show excellent thermal stability but also remain intact in aqueous solution within an extensive pH range. Moreover, the atomic absorption spectroscopy analysis experiment indicates that there does not exist the leaching of Pb2+ ions from the lead phosphonates, which show they are nontoxic in aqueous solution. In compound 1, the Pb(1)O4, Pb(2)O7, Pb(3)O4, and CPO3 polyhedra are interlinked into a one-dimensional chain, which is further connected to adjacent chain by sharing the Hssc2? to form a 2D layer. Interestingly, compound 1 as a highly selective and sensitive luminescent material can be used to detect the thymine molecule with a very low detection limit of 8.26 × 10?7 M. In compound 2, the Pb(1)O6 and Pb(2)O5 polyhedra are interlinked into a dimer via edge sharing, which is further connected to adjacent dimer to form a tetramer via corner sharing, and such a tetramer is then interlinked into a 2D layer through bts3? ligands; the adjacent 2D layers are finally constructed to a 3D structure by sharing the L24? ligand. Compound 2 can be applied as an excellent luminescent sensor for sensing of VO3? anion. Furthermore, the probable fluorescent quenching mechanisms of the two compounds have also been studied.
关键词： chemical stability,luminescent lead phosphonates,VO3? anion,thermal stability,hydrothermal techniques,fluorescent quenching mechanisms,thymine molecule
更新于2025-09-10 09:29:36
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Enhanced Photocatalytic Activity of TiO <sub/>2</sub> Nanotubes with Acid Treatments
摘要： In this work, we present the enhanced photocatalytic activity of TiO2 nanotubes (TNTs) by hydrothermal method with acid treatment. Firstly, TNTs were synthesized by using a hydrothermal method from commercial TiO2 powder in a 10 M NaOH solution at 130 (cid:3)C for 22 hours. The synthesized solid product after synthesis was then treated by three different post washing procedures: (i) distilled water, (ii) 2 M HCl + distilled water, and (iii) 2 M HNO3 + distilled water. The morphology, structural, and chemical composition of the washed TNT nanostructures were characterized by using the transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive X-ray diffraction (EDX). The photocatalytic activities of TNTs were then evaluated through the photocatalytic degradation of the methylene blue (MB) solution. The results reveal that the post washing procedures affect the uniformity, Na impurity of the achieved TNTs and the reduction of Na impurity content, makes for ef?cient photocatalytic properties.
关键词： Photocatalytic,Titanium Dioxide Nanotubes,Hydrothermal Process,Washing
更新于2025-09-09 09:28:46
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Multipurpose sensing applications of biocompatible radish-derived carbon dots as Cu2+ and acetic acid vapor sensors
摘要： A recent trend in the preparation of carbon dots, an optically unique nanomaterials, revolves around the use of readily-available, low-cost natural resources as precursors and their multipurpose applications. In this work, a hydrothermal method for preparing biocompatible carbon dots from radish was developed. The carbon dots were then tested for sensing of Cu2+ and acetic acid vapor. The carbon dots exhibited blue emission under UV illumination with, a quantum yield of 15%. The fluorescence emission was selectively quenched when Cu2+ ions were added, giving a detection limit of 0.16 μM. A paper-based fluorescent sensor was fabricated and shown to sense Cu2+ with a limit of detection of 6.8 μM. The carbon dots were able to determine the Cu2+ concentration in real water samples, with excellent recovery and reliability. The carbon dots were also used as the sensing material in an optical electronic nose, and tested for real-time detection of acetic acid vapor. Using principal component analysis, different ratios of acetic acid to methanol in solution were successfully identified with a detection limit of 15.5%. The acetic acid concentration in a real vinegar sample was also accurately determined. Our results demonstrated that label-free carbon dots derived from readily available radish can be simply used as versatile probes, giving them potential uses in multipurpose sensing applications.
关键词： Radish,Hydrothermal,Carbon dots,Vapor sensor,Cu2+ sensor
更新于2025-09-09 09:28:46
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Morphological evolution of upconversion nanoparticles and their biomedical signal generation
摘要： Advancements in the fabrication of upconversion nanoparticles (UCNPs) for synthetic control can enable a broad range of applications in biomedical systems. Herein, we experimentally verified the role of the hydrothermal reaction (HR) time in the synthesis of NaYF4:20%Yb3+/3%Er3+ UCNPs on their morphological evolution and phase transformation at different temperatures. Characterizations of the as-prepared UCNPs were conducted using X-ray diffraction (XRD), electron microscopy and spectroscopy, and thermogravimetric and upconversion (UC) luminescence analysis. We demonstrated that determining the optimal HR time, also referred to here as the threshold time, can produce particles with good homogeneity, hexagonal phase, and UC luminescence efficiency. Subsequently, the polymer coated UCNPs maintained their original particle size distribution and luminescence properties, and showed improved dispersibility in a variety of solvents, cellular nontoxicity, in vitro bioimaging, and biocompatibility as compared to the bare UCNP. Besides this, polyacrylic acid conjugated UCNPs (UCNP@PAA) also revealed the strong anticancer effect by conjugating with doxorubicin (DOX) as compared to the free DOX. Based on these findings, we suggest that these particles will be useful in drug-delivery systems and as in vivo bioimaging agents synchronously.
关键词： phase transformation,morphological evolution,biomedical applications,hydrothermal reaction,upconversion nanoparticles
更新于2025-09-09 09:28:46
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Fluorometric determination of hydroquinone by using blue emitting N/S/P-codoped carbon dots
摘要： N/S/P-codoped carbon dots (CDs) are shown to be a viable fluorescent probe in a turn-off-on fluorometric assay for hydroquinone (HQ). The preparation of CDs was carried out using a one-step hydrothermal reaction starting with glyoxal and isocarbophos. The method is based on the formation of ground state complexes between CD and Fe(III) which leads to quenching of blue fluorescence (with excitation/emission peaks at 363/448 nm). On addition of HQ, it will be oxidized by Fe(III) upon which fluorescence recovers. This turn-off-on system can be utilized to quantify HQ. A linear relationship exists between fluorescence recovery and HQ concentration in range between 0.56 and 375 μM. The limit of detection is 0.16 μM. The assay was successfully applied to the determination of HQ in spiked water samples and developer samples.
关键词： Developer samples,Blue emission,1,4-dihydroxybenzene,Glyoxal,Fluorescence turn-off-on system,Heteroatoms,Carbon dots,Water samples,Hydrothermal reaction,Fe(III)
更新于2025-09-09 09:28:46
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One-step introduction of metallic Bi and non-metallic C in Bi2WO6 with enhanced photocatalytic activity
摘要： One-step introduction of metallic Bi, non-metallic C into Bi2WO6 was successfully prepared via a facile hydrothermal synthetic route. The obtained materials were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy (XPS), nitrogen absorption–desorption isotherms, photoluminescence spectroscopy, photocurrent responses, electrochemical impedance spectroscopy (EIS), electron paramagnetic resonance (EPR), UV–vis diffuse reflectance spectra (DRS). As a result, C/Bi codecorated Bi2WO6 shows profoundly photocatalytic activity in comparison with undoped Bi2WO6 for decomposition of various industrial pollutants, including phenol, ciprofloxacin, bisphenol A, rhodamine B, and methyl orange under visible light (λ ≥ 420 nm). The enhanced photocatalytic properties may be ascribed to the fact that the synergistic effects of the SPR effect of Bi metal and the hybrid orbital constructed by C doping not only enhance the absorption of visible light but also accelerate the separation and migration of photo-generated carriers. Moreover, on the basis of the radical species trapping experiments, EPR analyses, DRS technique and Mott–Schottky plots, we proposed a simple photocatalytic mechanism.
关键词： Non-metallic C,Bi2WO6,Hydrothermal synthesis,Metallic Bi,Photocatalytic activity
更新于2025-09-09 09:28:46
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Highly efficient ethanol gas sensor based on hierarchical SnO2/Zn2SnO4 porous spheres
摘要： In this work, hierarchucal porous SnO2/Zn2SnO4 nanospheres were succesfully prepared via a facile one-step hydrothermal method with subsequent calcination process. Scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed in order to investigate the structural and morphological properties of the as-prepared composites. The results showed that the SnO2/Zn2SnO4 composites were cpmposed of many porous nanospheres with a uniform diameter of about 500 nm. Moreover, the as-prepared products were used as sensing material for the fabrication of gas sensor. The sensing performance of the sensor was systematically evaluated, and the sensor exhibited excellent ethanol-sensing property. The optimum operating temperature was 250 oC with a reponse of 30.5 toward 100 ppm ethanol. Also, the sensor showed good selectivity, stability and a low detection limit of 0.5 ppm (response 1.4). The good sensing performance of SnO2/Zn2SnO4 nanospheres can be attibuted to the porous structure as well as the heterojunction formed between SnO2 and ZnSn2O4.
关键词： SnO2/Zn2SnO4,Porous sphere,Hydrothermal method,Ethanol,Gas sensor
更新于2025-09-09 09:28:46
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Influence of Modifiers on the Morphology and Functional Properties of Vanadium Dioxide
摘要： Vanadium dioxide nanoparticles were obtained by the hydrothermal synthesis method in the presence of soluble Mo and W compounds as nucleating agents and of potassium and sodium chlorides as growth limiters. The influence of modifiers nature and synthesis conditions on the phase composition of the resulting product was studied.
关键词： layered oxides,hydrothermal synthesis,vanadium dioxide,nanoparticles,lithium-ion batteries
更新于2025-09-09 09:28:46
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1D Piezoelectric BaTiO3 Polycrystal of Topochemical Mesocrystal Conversion from Layered H2Ti4O9?H2O Single Crystal
摘要： A 1D piezoelectric BaTiO3 (BT) polycrystal with a tetragonal system was controllably prepared using a one-step hydrothermal soft chemical process. A layered H2Ti4O9·H2O (HTO) single crystal was used as the precursor. Interestingly, the obtained polycrystalline BT constructed from oriented BT nanoparticles shows a set of single-crystalline diffraction points, implying that the BT polycrystal is a mesocrystal. The [010] and [001] directions of the obtained mesocrystalline BT correspond to the [001] and [010] directions of the original HTO crystal, respectively, and the [010] direction of the mesocrystalline BT corresponds to the direction along the length of a 1D rod matrix. An in situ topochemical mesocrystal conversion of mesocrystalline BT grown on the HTO substrate occurred not only on the substrate surface but also in the interlayers owing to the unique TiO6 octahedral layers of HTO. In addition, the piezoelectric response of 1D mesocrystal was captured for the first time. The piezoelectric property of BT mesocrystals hinges on its nanostructure. It is a challenge to develop a special process to prepare highly 1D anisotropic perovskite titanate polycrystals with high crystallinity and piezoelectric response. This novel strategy can be utilized to develop piezoelectric mesocrystalline materials.
关键词： layered H2Ti4O9·H2O single crystal,1D piezoelectric BaTiO3,piezoelectric response,hydrothermal soft chemical process,topochemical mesocrystal conversion
更新于2025-09-09 09:28:46