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- 2019
- Au nanoparticles in water
- Fourier-Zhukovsky thermal model
- Nanomaterials and Technology
- National Institute for Laser, Plasma and Radiation Physics
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Laser-induced synthesis and photocatalytic properties of hybrid organic–inorganic composite layers
摘要： A laser-based method was developed for the synthesis and simultaneous deposition of multicomponent hybrid thin layers consisting of nanoentities, graphene oxide (GO) platelets, transition metal oxide nanoparticles, urea, and graphitic carbon nitride (g-C3N4) for environmental applications. The photocatalytic properties of the layers were tested through the degradation of methyl orange organic dye probing molecule. It was further demonstrated that the synthesized hybrid compounds are suitable for the photodegradation of chloramphenicol, a widely used broad-spectrum antibiotic, active against Gram-positive and Gram-negative bacteria. However, released in aquatic media represents a serious environmental hazard, especially owing to the formation of antibiotic-resistant bacteria. The obtained results revealed that organic, urea molecules can become an alternative to noble metals co-catalysts, promoting the separation and transfer of photoinduced charge carriers in catalytic composite systems. Laser radiation induces the reduction of GO platelets and the formation of graphene-like material. During the same synthesis process, g-C3N4 was produced, by laser pyrolysis of urea molecules, without any additional heat treatment. The layers exhibit high photocatalytic activity, being a promising material for photodegradation of organic pollutants in wastewater.
关键词： transition metal oxide nanoparticles,urea,photocatalytic properties,hybrid organic–inorganic composite layers,graphene oxide,graphitic carbon nitride,methyl orange,laser-based synthesis,chloramphenicol
更新于2025-11-14 17:04:02
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Synthesis of CoNi bimetallic alloy nanoparticles wrapped in nitrogen-doped graphite-like carbon shells and their electrocatalytic activity when used in a counter electrode for dye-sensitized solar cells
摘要： Nanoparticles of the bimetallic alloy CoNi wrapped in nitrogen-doped graphite-like carbon shells and dispersed on nitrogen-doped graphite-like carbon sheets (CoxNi1?x@NC) were synthesized by calcining CoNi metal–organic frameworks that were prepared through a facile solvothermal reaction using various raw-material molar ratios Co:Ni and CoNi:ethylenedinitrilotetraacetic acid. After depositing CoxNi1?x@NC for use as a counter electrode film in dye-sensitized solar cells, it was found that the electrocatalytic activity of the CoxNi1?x@NC counter electrode towards triiodide reduction could be optimized by simply tuning the molar ratios (Co:Ni and CoNi:ethylenedinitrilotetraacetic acid) appropriately during CoxNi1?x@NC synthesis. Cells that utilized a CoxNi1?x@NC counter electrode exhibited strong chemical-composition-dependent photovoltaic performance. Under optimal conditions, the CoxNi1?x@NC counter electrode presented an impressive energy conversion efficiency of 3.58%, suggesting that it is a highly promising counter electrode for application in dye-sensitized solar cells. This counter electrode has the advantages that it is considerably less expensive than a Pt counter electrode and that it provides the basis for the design and preparation of other inexpensive and efficient counter electrodes to replace Pt.
关键词： Photovoltaic performance,Dye-sensitized solar cells,CoNi alloy bimetallic nanoparticles,Counter electrode,Electrocatalytic activity
更新于2025-11-14 17:04:02
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Ligand-assisted synthesis of monodispersed and small-sized ZnO nanoparticles and their application in electroluminescence device
摘要： ZnO nanoparticle thin film has been demonstrated to be the best electron transportation material in quantum dot-based light emitting diodes (QD-LEDs). Therefore, the synthesis of well-dispersed and size-controllable ZnO nanoparticles is highly desirable. In this work, we present a facile and reproducible approach for the controllable synthesis of well-dispersed and monodispersed ZnO nanoparticles by using short-chain ethanolamine as the capping agent. It was found that ethanolamine plays an important role in the synthesis of monodispersed ZnO nanoparticles by controlling the nucleation and growth process. As a result, well-dispersed and size-controllable ZnO nanoparticles can be obtained. Compared with ligand-free conventional methods, our ligand-assisted approach has a higher reproducibility and a better controllability. We notice that QD-LEDs based on ligand-assisted ZnO exhibit a superior electroluminescence (EL) performance than those of traditional ZnO.
关键词： nanoparticles,ZnO,QD-LEDs,electroluminescence
更新于2025-11-14 17:04:02
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Ultrathin and Isotropic Metal Sulfide Wrapping on Plasmonic Metal Nanoparticles for SERS-based Detection of Trace Heavy Metal Ions.
摘要： A facile and general strategy is presented for homogenous and ultrathin metal sulfide-wrapping on plasmonic metal (PM) nanoparticles (NPs) based on a thiourea-induced isotropic shell growth. This strategy is typically implemented just via adding the thiourea into pre-formed PM colloidal solutions containing target metal ions. The validity of this strategy is demonstrated by taking the wrapped NPs with Au core and CuS shell or Au@CuS NPs as an example. They are successfully fabricated via adding the thiourea and Cu2+ solutions into pre-formed Au NP colloidal solution. The CuS shell layer is highly homogenous (<10% in relative standard deviation of shell thickness), regardless of the NPs’ shape or curvature. The shell thickness can be controlled from tens down to 0.5 nm just by the addition amounts of the shell precursors. The formation of the shell layer on the Au NPs can be attributed to the alternative deposition of Cu2+ and S2- ions on the thiourea-modified surface of Au NPs in the solution, which induces the isotropic shell growth. Further, this strategy is of good universality. Many other sulfide-wrapped PM NPs, such as Ag@CuS, Au@PtS2, Au@HgS, Ag@Ag2S NPs and Ag@CuS nanorods have been successfully obtained with homogeneous and ultrathin shells. Importantly, such ultrathin sulfide-wrapped PM NPs can be used for SERS-based detection of trace heavy metal ions with strong anti-interference via ion exchange process between the metal sulfide shell and heavy metal ions. This study provides a simple and controllable route for wrapping the homogenous and ultrathin sulfide layers on the PM NPs, and such wrapped NPs have good practical applications in the SERS-based detection of trace heavy metal ions.
关键词： Plasmonic metal nanoparticles,Trace heavy metal ions,Ultrathin sulfide wrapping,Thiourea-induced isotropic shell growth,SERS-based detection
更新于2025-11-14 17:04:02
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Controllable preparation of phase-separated Pb/Zn heterogeneous nanoparticles by laser ablation and their application in the growth of PbS tipped ZnS nanorods heterostructures
摘要： Phase-separated Pb/Zn heterogeneous nanoparticles (Pb/Zn HNPs) with a controllable phase ratio were firstly prepared by long-pulse-width millisecond laser ablation of Pb/Zn binary metal target immersed in anhydrous ethanol under room conditions. The phase ratio in the as-ablated Pb/Zn HNPs was mainly determined by the molar ratio of Pb/Zn in the initial binary metal target and the structure of Pb/Zn HNPs was partly influenced by the pulse laser width. Then the PBS tipped ZnS nanorods heterostructures (PbS/ZnS heterostructures) were grown by simply heating the mixture of the as-ablated Pb/Zn HNPs and thioacetamide (TAA) at 450 (cid:1)C in a tube furnace. The size and morphology of Pbs/ZnS heterostructures were decided by the original absolute size and relative size between phase-separated Pb and Zn nanoparticle. The formation of Pbs/ZnS heterostructures was the result of the diffusion-limited of S atoms in the Pb/Zn HNPs. This study not only provides a new strategy for the controllable preparation of phase-separated bimetallic nanoparticles that can be used for the growth of specific heterostructures but a new view on the fundamental physical and chemical aspects of nanocrystal formation after laser ablation of solids in liquids.
关键词： Heterostructure,Phase-separated,Heterogeneous nanoparticles,Laser ablation,Binary metal target,Diffusion-limited
更新于2025-11-14 17:04:02
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Plasmonic Au nanoparticles supported on both sides of TiO2 hollow spheres for maximising photocatalytic activity under visible light
摘要： A strategy of intensifying the visible light harvesting ability of anatase TiO2 hollow spheres (HSs) was developed, in which both sides of TiO2 HSs were utilised for stabilising Au nanoparticles (NPs) through the sacrificial templating method and convex surface-induced confinement. The composite structure of single Au NP yolk-TiO2 shell-Au NPs, denoted as Au@Au(TiO2, was rendered and confirmed by the transmission electron microscopy analysis. Au@Au(TiO2 showed enhanced photocatalytic activity in the degradation of methylene blue and phenol in aqueous phase under visible light reference materials such as surpassing that of other Au(TiO2 by 77% and Au@P25 by 52%, respectively, in phenol degradation.
关键词： confinement,photocatalytic degradation,visible light,TiO2 hollow spheres,plasmonic Au nanoparticles
更新于2025-11-14 17:04:02
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Simultaneous enhancement of red upconversion luminescence and CT contrast of NaGdF <sub/>4</sub> :Yb,Er nanoparticles <i>via</i> Lu <sup>3+</sup> doping
摘要： To date, lanthanide-doped upconversion nanoparticles (UCNPs) have been widely reported as a promising CT contrast agent because they have high atomic numbers and big X-ray attenuation coefficient values. However, it is still a challenge to fabricate a simple multimodal imaging probe with improved image quality for early cancer diagnosis in clinical medicine. Herein, ultra-small, uniform and monodisperse β-NaGdF4:Yb,Er,X% Lu (X = 0, 1, 2.5, 4, 6, 7.5) UCNPs were prepared through a solvothermal method with high-level modulation of both the phase and morphology. Meanwhile, a remarkably enhanced red upconversion luminescence (UCL) in the β-NaGdF4:Yb,Er,X% Lu NPs was successfully realized via Lu3+ doping. It is found that as the content of Lu3+ increases from 0 to 7.5 mol%, the UCL intensity of the red emission first increases and then decreases, with the optimum doping content of Lu3+ ions of 2.5 mol%. The red UCL enhancement is ascribed to the change of the Yb–Er interionic distance controlling the Yb–Er energy transfer rate and the distortion of the local environment of Er3+ ions influencing the 4f–4f transition rates of Er3+ ions, which has been further confirmed by the experimental check of the crystallographic phase and by photoluminescence spectroscopy employing Eu3+ as the structural probe, respectively. More importantly, after being modified with the HS-PEG2000-NH2 ligand, the NH2-PEGylated-NaGdF4:Yb,Er,X% Lu NPs exhibited low cytotoxicity, high biocompatibility, and remarkably enhanced contrast performance in in vitro UCL and in vivo CT imaging. On the basis of our findings, the as-obtained functionalized UCNPs could be considered as a promising versatile dual-mode imaging probe for bioimaging, tumor diagnosis, and cancer therapy.
关键词： red luminescence enhancement,Lu3+ doping,upconversion nanoparticles,multimodal imaging,CT contrast
更新于2025-11-14 17:04:02
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Silver Nanoparticles - Fabrication, Characterization and Applications || Synthesis and Optical Properties of Highly Stabilized Peptide- Coated Silver Nanoparticles
摘要： The interaction between the silver nanoparticle and peptide surfaces has been of increased interest for the applications of bionanotechnology and tissue engineering. In order to completely understand such interactions, we have examined the optical properties of peptide-coated silver nanoparticles. However, the effect of peptide binding motif upon the silver nanoparticles surface characteristics and physicochemical properties of these nanoparticles remains incompletely understood. Here, we have fabricated sodium citrate stabilized silver nanoparticles and coated with peptide IVD (ID3). The optical properties of these peptide-capped nanomaterials were characterized by UV-visible, transmission electron microscopy (TEM), and z-potential measurement. The results indicate that the interface of silver nanoparticles (AgNP)-peptide is generated using ID3 peptide and sug-gested that the reactivity of peptide is governed by the conformation of the bound pep-tide on the silver nanoparticle surface. The interactions of peptide-nanoparticle would potentially be used to fabricate specific functionality into the various peptide-capped nanomaterials and antibacterial applications.
关键词： Z-potential,silver nanoparticles,peptide,physicochemical properties
更新于2025-11-14 17:04:02
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Probing Electrocatalytic CO2 Reduction at Individual Cu Nanostructures via Optically Targeted Electrochemical Cell Microscopy
摘要： Optically targeted electrochemical cell microscopy (OTECCM) was applied to measure electrocatalytic rates at individual Cu nanoparticles (NPs) under electrolyte conditions relevant to CO2 reduction. The electrocatalytic responses from individual NPs were found to exhibit a wide variation in behavior, with significant NP-to-NP variations in the magnitude of electrocatalytic currents and necessary overpotentials being observed. Correlations of these quantities with metrics of NP size suggest no significant variations in the inherent electrocatalytic activity of the NPs with size. Finite element simulations of diffusion in this system demonstrate the observed diffusion-limited currents are significantly smaller than expected, attributable to the presence of a significant amount of residual ligand on the surface of the Cu NPs, which were prepared via an organic phase synthesis. The results presented here further demonstrate the promise of techniques which employ correlated optical and electrochemical measurements, such as OTECCM, for studying electrocatalysis at individual NPs.
关键词： Nanoparticles,Electrochemical microscopy,Electrochemistry,CO2 reduction
更新于2025-11-14 17:03:37
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One-pot bottom-up fabrication of biocompatible PEGylated WS2 nanoparticles for CT-guided photothermal therapy of tumors in?vivo
摘要： Background: Tungsten disulfide (WS2), which enjoyed a good potential to be a promising clinical theranostic agent for cancer treatment, is still subject to the tedious synthesis procedure. Methods: Here, we reported a one-pot 'bottom-up' hydrothermal strategy for the fabrication of PEGylated WS2 nanoparticles (NPs). The WS2-PEG nanoparticles were characterized systematically. The CT imaging and photothermal therapy against tumor as well as biosafety in vitro and in vivo were also investigated. Results: The obtained WS2-PEG NPs enjoyed obvious merits of good solubility and favorable photothermal performance. WS2-PEG NPs exhibited desirable photothermal ablation ability against cancer cells and cancer cell-bearing mice in vitro and in vivo. MTT assay and histological analysis demonstrated the low cytotoxicity and biotoxicity of WS2-PEG NPs, providing a valid biosafety guarantee for the coming biomedical applications. In addition, thanks to the obvious X-ray attenuation of W atom, the WS2-PEG NPs can also be served as a favorable contrast agent for CT imaging of tumors. Conclusion: WS2-PEG NPs has enjoyed a good potential to be a promising clinical CT-guided photothermal therapeutic agent against cancers.
关键词： Photothermal therapy,Computed tomography,WS2,Tumor,Nanoparticles
更新于2025-11-14 17:03:37