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A comparative study on photocatalytic hydrogen evolution activity of synthesis methods of CDs/ZnIn2S4 photocatalysts
摘要： The introduction of carbon materials in photocatalytic systems can significantly enhance the photocatalytic hydrogen evolution activity. Here, we proposed and fabricated carbon nanodots/ZnIn2S4 (CDs/ZIS) samples via three methods. The morphology, chemical elements and valence, and photoelectric properties of CDs/ZIS samples were systematically characterized by SEM, TEM, XPS, UV and PL. The photocatalytic H2 production experiments indicate that the photocatalytic performance of all CDs/ZIS samples has been significantly improved, which could be attributed to the fact that serving as an excellent electron acceptor, CDs can accelerate the separation efficiency of photogenerated electrons and holes. The samples prepared via one-pot hydrothermal method exhibit the optimal photocatalytic activity and the corresponding H2 production rate of 4.15 mmol g?1 h?1 under visible light irradiation (λ > 420 nm), which is about 2.92 times higher than pure ZIS. Our work presented the influence of synthetic method on photoelectric performance and photocatalytic activity of CDs/ZIS nanocomposites, and provided a reliable idea for improving the photocatalytic performance of photocatalyst toward practical applications.
关键词： Synthesis methods,ZnIn2S4,Photocatalytic hydrogen evolution,Carbon dots
更新于2025-11-14 15:29:11
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Synthesis of Tungsten Disulfide and Molybdenum Disulfide Quantum Dots and their Applications
摘要： With fascinating optical, electronic, and mechanical properties, tungsten disulfide (WS2) and molybdenum disulfide (MoS2) quantum dots (QDs) are promising for related applications. Their bandgap energy, photoluminescence and electrochemical properties are closely related to their size, morphology, dimensionality, crystal phase and structure. In this review, we introduce the crystal phases and structures of WS2 and MoS2 QDs followed by a summary of their physical and chemical synthetic methods and their applications in light-emitting devices (LEDs), supercapacitors and others. Additionally, the advantages and limitations of different synthetic strategies and challenges in these promising fields are discussed on the basis of current development.
关键词： Synthesis methods,Applications,Quantum dots,Molybdenum disulfide,Tungsten disulfide
更新于2025-09-23 15:21:01
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Electrical response of mixed phase (1-x)BiFeO3-xPbTiO3 solid solution: Role of tetragonal phase and tetragonality
摘要： We present the study of structural, morphological, dielectric, transport and ferroelectric properties of (1-x)BFO–xPTO solid solutions, with 0.3 ≤ x ≤ 0.6, prepared via non-conventional synthesis methods. These methods include Sol-gel and Single-step solid state method. Structural analysis revealed presence of mixed phases i.e. monoclinic (CC) and tetragonal (P4mm) phases, for all compositions showing a Morphotropic Phase Boundary. For the compositions with higher concentration of PTO, an increase in tetragonal phase fraction has been observed. Quantitative analysis showed, in general, higher value of c/a (i.e. tetragonality) for all samples as compared to the bulk PTO. The morphological analysis shows small grain size irrespective of synthesis method and composition. The low temperature frequency dependent tangent loss shows dielectric relaxation with small magnitude of dielectric constant indicating absence of extrinsic contributions. High temperature dielectric anomaly is observed around 400-500 K corresponding to magnetic phase transformation of BFO at Neel temperature which suggest the presence of magneto-electric coupling in specific compositions. Sol-gel prepared composite appeared to be more resistive than the Single-step synthesized composite and shows Arrhenius type dependence of high temperature ac conductivity. Ferroelectricity was observed in all ceramic samples which sustained high applied electric field up to 190 kV/cm. Finally, a correlation between polarization, tetragonal phase fraction and c/a ratio, has been drawn and discussed. It is concluded that c/a ratio (i.e. tetragonality) is more important parameter which can be tuned to achieve enhanced ferroelectric response as compared to the tetragonal phase fraction in (1-x)BFO–xPTO solid solutions.
关键词： Electric polarization,Non-conventional synthesis methods,Tetragonality,Morphotropic phase boundary,Ferroelectricity,Phase evolution,Dielectric anomalies
更新于2025-09-19 17:15:36
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Lead chalcogenide quantum dots for photoelectric devices
摘要： The review concerns the state of the art in methods of synthesis of colloidal lead chalcogenide quantum dots (QDs). The most recent data on the mechanisms of chemical transformations involving various precursors are discussed. Particular attention is paid to the influence of (i) trace impurities in the reactants used and (ii) post-synthesis treatment on the physicochemical properties of QDs used in photoelectric devices. The bibliography includes 129 references.
关键词： photoelectric devices,quantum dots,colloidal synthesis,lead chalcogenide,synthesis methods
更新于2025-09-16 10:30:52
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Recent development on modification of synthesized barium titanate (BaTiO3) and polymer/BaTiO3 dielectric composites
摘要： In order to fabricate barium titanate (BaTiO3) particles with high purity, small particle size and narrow distribution of particle size, the synthesis methods and doping elements should be properly selected. Compared to polar polymers, non-polar polymers have advantages on the fabrication of miniaturized and lightweight electronic devices, due to excellent process-ability and little endogenous heat generated in the electric field. To avoid the aggregation of BaTiO3 particles in polymer matrix, several nanometer thick organic coating on the BaTiO3 surface is needed. What’s more, the alignment of BaTiO3 and hybrid use of fillers can further improve the dielectric properties of polymer/BaTiO3 composites.
关键词： Barium titanate,Synthesis methods,Dielectric properties,Surface modification,Polymer composites
更新于2025-09-04 15:30:14