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Manipulated interparticle gaps of silver nanoparticles by dendron-exfoliated reduced graphene oxide nanohybrids for SERS detection
摘要： We have successfully prepared a floating-typed surface-enhanced Raman scattering (SERS) substrate by the uniform nanoparticle arrays of silver nanoparticles (AgNPs) immobilized on the dendron-exfoliated reduced graphene oxide (rGO) nanosheets. These poly(urea/malonamide) dendrons were precisely synthesized, and then grafted on the dendron-exfoliated rGO nanosheets based on an efficient building block of dual functional 4-isocyanato-4′-(3,3-dimethyl-2,4-dioxo-azetidino)-diphenylmethane (IDD). By using dendron-rGO nanosheets as templates for hosting AgNPs, the particle size (D) and interparticle gap (W) of AgNPs could be manipulated by the incorporation of dendrons of various generations (0.5, 1.5, and 2.5 generations), evaluated by transmission electron microscopy. The results indicate that the nanohybrids with 1.5 generation-dendron exhibited stable, enormous, and linear-quantitative Raman enhancement in malachite green detection (1–100 ppm), due to the lowest W/D ratio (0.85 ± 0.60) and interparticle gap (7.60 ± 5.29 nm). The limit of detection (LOD) of malachite green is lower than 2.7 × 10?11 M (0.01 ppb). AgNPs@rGO-dendritic derivative nanohybrids as floating and flexible SERS substrates provide ultrasensitive and stable SERS detection in the solutions, which offers great potential for practical applications in detecting environmental pollutants.
关键词： Silver nanoparticles,Reduced graphene oxide nanosheets,Surface-enhanced Raman scattering detection,Dendritic polymers
更新于2025-09-11 14:15:04
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Cu-Fe-Se Ternary Nanosheet-Based Drug Delivery Carrier for Multimodal Imaging and Combined Chemo-photothermal Therapy of Cancer
摘要： Ternary transition-metal chalcogenide nanosheets have shown great potential in diverse applications owing to their intrinsically amazing properties with broad tunable window. Direct preparation of water-soluble and biocompatible ternary chalcogenide nanosheets for theranostic application remains a challenge. In this article, we prepared Cu-Fe-Se nanosheets (CFS NSs) in an aqueous solution under ambient conditions by sequential coprecipitation method. They were functionalized with anticancer drug doxorubin (CFS@DOX) through electrostatic interactions, and labeled with radioactive isotope 99mTc through surface coordination effect. The resulting nanosheets have a size of 70 nm and a thickness of 5 nm, and can be well dispersed in water, PBS, 10% FBS, and 0.9% NaCl with an excellent colloidal stability. They also exhibit a high photothermal conversion efficiency of 78.9% for in vitro and in vivo photoacoustic imaging and photothermal therapy. The isotope-labelled nanosheets (99mTc-CFS NSs) were used for single photon emission computed tomography/computed tomography (SPECT/CT) imaging, and quantification of their blood circulation time (~4.7 h) and biodistributions in major organs, which follow an order of liver > bladder > lung > spleen > heart > kidney. The DOX functionalized nanosheets (CFS@DOX) were used for chemotherapy of cancer and exhibited excellent anti-cancer efficacy. Our research shows the great promise of ternary metal chalcogenide nanosheets for combined imaging and therapy of cancer.
关键词： radiolabeling,2D ternary nanosheets,transition metal chalcogenides,multimodal imaging,chemotherapy,photothermal therapy
更新于2025-09-11 14:15:04
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Ultrathin WO3 nanosheets modified by g-C3N4 for highly efficient acetone vapor detection
摘要： In this work, ultrathin WO3 nanosheets were prepared by self-assembly approach and their phase and morphology were regulated by changing the heat treatment temperature. Then, g-C3N4 modified WO3 nanosheets sensitive material was fabricated via a facile liquid ultrasonic mixing method. The microstructure, morphology, chemical composition, oxidation state and surface area of WO3 nanosheets and g-C3N4/WO3 nanocomposite were comparatively studied by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). Sensing performances of WO3 nanosheets and g-C3N4/WO3 composite with different g-C3N4 loading amount were investigated with acetone as a target gas. Compared to WO3 nanosheets, the g-C3N4/WO3 gas sensor exhibits good response, excellent selectivity, transient response and trace detection ability to acetone vapor. Effects of g-C3N4 content on gas sensitivity were also investigated. The response (Ra/Rg) of the gas sensor based on 1 wt% g-C3N4/WO3 was 35 toward 100 ppm acetone at 340 °C, which was about 300% higher than the response value of pure WO3 sensor. The sensor also showed a fast response/recovery speed (9 s/3.8 s) and a wide linear detection range (from 0.5 ppm to 500 ppm). These unique sensing properties were attributed to the synergistic effects including the contribution of WO3 ultrathin nanosheets, suitable crystal phase and porous surface, and the sensitization of g-C3N4, which increases the specific surface area and regulates the electrical properties. This work will contribute to the development of new acetone sensors and expand the application of g-C3N4 composite materials.
关键词： g-C3N4 nanosheets,acetone detection,nanocomposites,WO3 nanosheets
更新于2025-09-10 09:29:36
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Photocatalytic reduction of CO2 to methane over PtOx-loaded ultrathin Bi2WO6 nanosheets
摘要： Solar CO2 photoreduction into hydrocarbons is promising and significative. However, many conventional catalysts reported usually suffer from poor photocatalytic activities. Herein, ultrathin Bi2WO6 nanosheets with a thickness of about 4.8 nm have been synthesized by hydrothermal method, which exhibited a CH4 production rate of 19 ppm g?1 h?1 under a low CO2 concentration of 400 ppm. PtOx nanoparticles with a size of about 2 nm were then loaded on the Bi2WO6 nanosheets as excellent co-catalysts by photoreduction in aqueous solution, and an optimal CH4 yield of 108.8 ppm g?1 h?1 was achieved, which was about 5.7 times than that of pristine Bi2WO6 nanosheets. Further analyses of photocurrent curves, electrochemical impedance spectroscopy and polarization curves of water oxidation indicated that the improved photocatalytic activity was suggested to result from the enhanced carrier separation and accelerated water oxidation by PtOx nanoparticles. The work will likely give a deeper insight of PtOx nanoparticles and provide a new idea to design catalysts for CO2 photoreduction to CH4.
关键词： PtOx nanoparticles,Carrier separation,Water oxidation,CO2 photoreduction,Bi2WO6 nanosheets
更新于2025-09-10 09:29:36
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Constructing hierarchical SnO2 nanofiber/nanosheets for efficient formaldehyde detection
摘要： SnO2 nanofiber/nanosheets with hierarchical nanostructures were successfully synthesized via a facile hydrothermal method by using hollow SnO2 nanofibers as the backbone. The microstructure, morphology, chemical composition, oxidation states and surface areas of SnO2 nanofibers, SnO2 nanofiber/nanosheets and SnO2 nanosheets were comparatively studied by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The characterization results indicated that the hierarchical SnO2 nanofiber/nanosheets were constructed by nanosheets arrays uniform growth on the surface of nanofibers. Sensing performances of SnO2-based nanomaterials were investigated utilizing formaldehyde (HCHO) as a target gas. Compared to SnO2 nanofibers, nanosheets and the physical mixture of nanofibers and nanosheets, the gas sensor based on SnO2 nanofiber/nanosheets exhibited better response, more excellent selectivity, transient response and trace detection ability to HCHO gas. The response (Ra/Rg) of the gas sensor is 57 toward 100 ppm HCHO at 120 °C, which is about 300% and 200% higher than that of pure SnO2 nanofibers sensors and SnO2 nanosheets sensors, respectively. Furthermore, the sensor has an excellent response/recovery performance with 4.7 s and 11.6 s for detecting 100 ppm HCHO. Both the growth process and the gas sensing mechanism of SnO2 hierarchical nanostructures were discussed. Successful preparation of SnO2 nanofiber/nanosheets is attributed to uniform decoration of seeds on the nanofibers and suitable growth conditions of nanosheets. Enhanced sensing performance mainly result from the synergistic effect of nanofibers and nanosheets, hierarchical structures and larger specific surface areas. The synthetic strategy can also be applied in preparing hierarchical materials of different constituent materials.
关键词： Homogeneous materials,SnO2 nanofiber/nanosheets,Formaldehyde gas sensors,Hierarchical structure
更新于2025-09-10 09:29:36
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Convenient Fabrication of Carbon Doped WO3-x Ultrathin Nanosheets for Photocatalytic Aerobic Oxidation of Amines
摘要： It is an important chemical transformation for oxidation of amines to imines, on account of very important versatile applications of imines in organic synthesis. Here, we develop a convenient way to synthesize carbon doped WO3-x ultrathin nanosheets via an acid-assisted one-pot process. The carbon doped WO3-x ultrathin nanosheets exhibit excellent photocatalytic activity in the aerobic oxidation of amines to corresponding imines under visible light irradiation at room temperature. The high catalytic performance is attributed to remarkable visible light absorption ability and effective absorption of molecular oxygen and substrates. Rich oxygen-vacancies existing in the carbon doped WO3-x ultrathin nanosheets may play an important role, because oxygen-vacancies not only change the band structure but also act as catalytic sites to activate molecular oxygen by photoproduct electrons to generate superoxide radicals. Both photoproduct holes and superoxide radicals play important role for the oxidation of amines.
关键词： Aerobic oxidation,Carbon dropping,WO3-x,Nanosheets,Photocatalytic
更新于2025-09-10 09:29:36
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Laser-induced improvement in tribological performances of surface coatings with MoS2 nanosheets and graphene
摘要： To deal with the corrosive property of bio-oil, laser-induced coatings were synthesized on the typical cylinder liner rubbing surfaces. Two nano-additives including MoS2 nanosheets and graphene were introduced into the coatings. The tribological performances of the coated surfaces were tested on a multifunctional cylinder liner-piston ring tribometer. The surfaces before and after sliding were characterized with modern surface analysis technology including Raman spectra, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and etc. The results show that the nickel-based coated surfaces can effectively prevent the corrosion of the bio-oil. In addition, the laser-induced coatings had better antifriction and antiwear performances than the corresponding traditional electroless plating coatings. With the introduction of MoS2 nanosheets or graphene, the tribological performances of the coatings were further enhanced. Laser irradiation increased the concentration of the nano-additives in the coatings and the thickness of the tribo-layers, which accounted for their outstanding tribological performances.
关键词： Laser-induced coating,Graphene,Bio-oil,MoS2 nanosheets,Tribological performance
更新于2025-09-10 09:29:36
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Ultrathin Visible-Light-Driven Mo Incorporating In <sub/>2</sub> O <sub/>3</sub> -ZnIn <sub/>2</sub> Se <sub/>4</sub> Z-Scheme Nanosheet Photocatalysts
摘要： Inspired by natural photosynthesis, the design of new Z-scheme photocatalytic systems is very promising for boosting the photocatalytic performance of H2 production and CO2 reduction; however, until now, the direct synthesis of efficient Z-scheme photocatalysts remains a grand challenge. Herein, it is demonstrated that an interesting Z-scheme photocatalyst can be constructed by coupling In2O3 and ZnIn2Se4 semiconductors based on theoretical calculations. Experimentally, a class of ultrathin In2O3–ZnIn2Se4 (denoted as In2O3–ZISe) spontaneous Z-scheme nanosheet photocatalysts for greatly enhancing photocatalytic H2 production is made. Furthermore, Mo atoms are incorporated in the Z-scheme In2O3–ZISe nanosheet photocatalyst by forming the Mo–Se bond, confirmed by X-ray photoelectron spectroscopy, in which the formed MoSe2 works as cocatalyst of the Z-scheme photocatalyst. As a consequence, such a unique structure of In2O3–ZISe–Mo makes it exhibit 21.7 and 232.6 times higher photocatalytic H2 evolution activity than those of In2O3–ZnIn2Se4 and In2O3 nanosheets, respectively. Moreover, In2O3–ZISe–Mo is also very stable for photocatalytic H2 production by showing almost no activity decay for 16 h test. Ultraviolet–visible diffuse reflectance spectra, photoluminescence spectroscopy, transient photocurrent spectra, and electrochemical impedance spectroscopy reveal that the enhanced photocatalytic performance of In2O3–ZISe–Mo is mainly attributed to its widened photoresponse range and effective carrier separation because of its special structure.
关键词： Z-scheme,nanosheets,ZnIn2Se4,photocatalysis
更新于2025-09-10 09:29:36
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Gold/WS2 nanocomposites fabricated by in-situ ultrasonication and assembling for photoelectrochemical immunosensing of carcinoembryonic antigen
摘要： Tungsten disulfide (WS2) nanosheets were obtained by exfoliating WS2 bulk crystals in N-methylpyrrolidone by ultrasonication. Gold nanoparticles (GNPs) were synthesized by in-situ ultrasonication of sodium citrate and HAuCl4 while fabricating the WS2 nanosheets. In this way, the GNPs were self-assembled on WS2 nanosheets to form a GNPs/WS2 nanocomposite through interaction between sulfur and gold atoms. The photoelectrochemical response of WS2 nanosheets is significantly enhanced after integration of the GNPs. The GNPs/WS2 nanocomposite was coated onto a glassy carbon electrode (GCE) to construct a sensing interface which then was modified with an antibody against the carcinoembryonic antigen (CEA) to obtain a photoelectrochemical immunosensor for CEA. Under optimized conditions, the decline in relative photocurrent is linearly related to the logarithm of the CEA concentration in the range from 0.001 to 40 ng mL?1. The detection limit is 0.5 pg mL?1 (at S/N = 3). The assay is sensitive, selective, stable and reproducible. It was applied to the determination of CEA in clinical serum samples.
关键词： Gold nanoparticles,CEA,Photoelectrochemistry,Nanosheets,Transition metal dichalcogenides,Immunosensor
更新于2025-09-10 09:29:36
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Ultrathin 2D Conjugated Polymer Nanosheets for Solar Fuel Generation
摘要： Two-dimensional (2D) polymers are fascinating as they exhibit unique physical, chemical, mechanical, and electronic properties that are completely different from those of traditional linear or branched polymers. They are very promising for applications in catalysis, separation, optoelectronics, energy storage, and nanomedicine. Recently, ultrathin 2D conjugated polymers have emerged as advanced materials for converting solar energy into chemical energy. The inherent 2D planar structure with in-plane periodicity offers many features that are highly desirable for photon-involved catalytic energy conversion processes, including high absorption coefficients, large surface areas, abundant surface active sites, and efficient charge separation. Moreover, the possibility of finely tuning the optoelectronic and structural properties through precise molecular engineering has opened up new opportunities for design and synthesis of novel 2D polymer nanosheets with unprecedented applications. Herein, we highlight recent advances in developing ultrathin 2D conjugated polymer nanosheets for solar-to-chemical energy conversion. Specifically, we discuss emerging applications of ultrathin 2D conjugated polymer nanosheets for solar-driven water splitting and CO2 reduction. Meanwhile, future challenges and prospects for design and synthesis of ultrathin 2D conjugated polymer nanosheets for solar fuel generation are also included.
关键词： Energy conversion,2D polymers,Nanosheets,Conjugated polymers,Photocatalysis
更新于2025-09-10 09:29:36