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One-pot Hydrothermal Synthesis of ZnO Microspheres/Graphene Hybrid and its Electrochemical Performance
摘要： In this paper, the ZnO microspheres/graphene hybrids were successfully prepared from zinc acetate and GO aqueous solution by a facile one-pot hydrothermal method without any surfactant. The as-synthesized samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), thermogravimetric (TGA) analysis, nitrogen adsorption/desorption isotherms and pore size distribution. When evaluated as anode material for lithium ion batteries, it delivered a high initial discharge capacity of 1150 mAh g-1 and exhibited excellent rate performance at different current densities.
关键词： anode materials,ZnO microspheres/graphene hybrid,one-pot hydrothermal,lithium ion batteries
更新于2025-09-23 15:21:01
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Hierarchical 3D VO2/ZnV2O4 microspheres as an excellent visible light photocatalyst for CO2 reduction to solar fuels
摘要： The photocatalytic reduction of CO2 has a great potential to produce fuels and chemicals, as well as, it reduces CO2 emission and addresses the environmental issues. To date single metal based catalysts still su?er from lower e?ciency, uncontrollable selectivity and instability. In this study, hierarchical microspheres (HMs) of ZnV2O4 with VO2 impurity were synthesized through the single step reduction process, to explore highly e?cient photocatalyst towards visible light responsive photocatalytic CO2 reduction. HMs of ZnV2O4 were successfully synthesized with mesoporous structure, higher surface area and functional under visible light irradiations. The ?1 were obtained over ZnV2O4 synthesized after highest yield of CO and CH3OH of 378 and 202 μmole g-cat 24 h of reaction time, respectively. The performance of optimized 3D HMs of ZnV2O4 for CO and CH3OH pro-duction was 2.30 folds and 10.7 folds higher than using ZnO/V2O5 composite sample, respectively. Other products detected with appreciable amounts were CH4 and C2H6. This reveals, HMs structure of ZnV2O4 not only allows the transfer of electrons towards CO2, but also provides short pathways for electron transfer and empty space in the microspheres will serve as the reservoirs to store the electrons, hence leading to enhanced photo-activity. In addition, VO2 presents in the sample further contribute to enhance performance of ZnV2O4 HMs due to enabling e?cient charge carrier separation. The prolong stability of ZnV2O4 in the CO2 reduction system con?rmed that 3D HMs structure provides controllable selectivity and stability. This brings to conclusions that fabrication of hierarchical structures will stimulate further development towards high performance photo-cat-alysts for the photocatalytic CO2 reduction to solar hydrocarbon fuels.
关键词： Hierarchical structure,CO2 reduction,Ternary metal oxide,Zinc vanadium oxide,3D microspheres of ZnV2O4,Hydrocarbon fuels
更新于2025-09-23 15:21:01
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Plasmonic Janus Microspheres Created from Pickering Emulsion Drops
摘要： Metal nanostructures have been created in a film format to develop unique plasmonic properties. Here, well-defined metal nanostructures are designed on the surface of microspheres to provide plasmonic microgranules. As conventional techniques are inadequate for nanofabrication on spherical surfaces, photocurable emulsion drops with a regular array of silica particles are employed at the interface to create periodic nanostructures. The silica particles, originating from the dispersed phase, fully cover the interface by forming a non-close-packed hexagonal array after drop generation, and slowly protrude to the continuous phase during aging while their interparticle separation decreases. Therefore, hexagonal arrays of spherical dimples with controlled geometry and separation are created on the surface of microspheres by photocuring the drops and removing the particles. Directional deposition of either aluminum or gold results in a continuous film with a hexagonal array of holes on the outermost surface and isolated curved disks in dimples, which renders the hemisphere of microspheres plasmonically colored. The resonant wavelength is controlled by adjusting the aging time, metal thickness, and size of silica particles, providing various plasmonic colors. This granular format of the plasmonic Janus microspheres will open a new avenue of optical applications including active color pixels, optical barcodes, and microsensors.
关键词： Janus microspheres,self-assembly,colloids,Pickering emulsions,plasmonic colors
更新于2025-09-23 15:21:01
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Nanosheets-assembled Bi2WO6 microspheres with efficient visible-light-driven photocatalytic activities
摘要： The nanosheet-assembled Bi2WO6 microspheres could be successfully synthesized in large quantities by a facile hydrothermal strategy in the presence of surfactant hexadecyl trimethyl ammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) under mild conditions. The morphology and size of as-prepared Bi2WO6 could be readily controlled by adjusting the synthetic parameters such as hydrothermal time. The probable formation mechanism of nanosheet-assembled Bi2WO6 microspheres was discussed in detail. The hierarchical nanosheet-assembled microspheres could be constructed by orderly arranged nanosheets. The photocatalytic activity of the nanosheet-assembled Bi2WO6 microspheres was evaluated by degrading rhodamine B (RhB) under irradiation of visible light. The brilliant photodegradation e?ciency is about 98% under visible light irradiation for 50 min. The results suggest that the as-prepared Bi2WO6 microspheres have good prospects as the photocatalyst for the removal of organic pollutants.
关键词： Hydrothermal,Bi2WO6,Visible light,Nanosheets,Microspheres,Photocatalysis
更新于2025-09-23 15:21:01
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Enhanced photocatalytic activity based on TiO <sub/>2</sub> hollow hierarchical microspheres/reduced graphene hybrid
摘要： A novel TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid was prepared by a facile and efficient two-step solvothermal synthesis method. The TiO2 HHMs with the size ～500 nm were uniformly distributed on the surface of rGO nanosheets. The as-prepared TiO2 HHMs/rGO hybrid is stable and exhibits a significantly higher photocatalytic activity (97.8%) for 40 ml of 10 mg/Rhodamine B (RhB) solution than that of the pure TiO2 microspheres (75.2%) and Degussa P25 (53.6%). The rGO nanosheet acts as a microelectrode for rapid accepting and separating the photogenerated electron on surface, which effectively slow the recombination rate of electrons and holes, and then effectively enhance the photocatalytic activity of the hybrid. The as-prepared novel TiO2 HHMs/rGO hybrid shows great promising for practical photocatalytic applications.
关键词： TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid,enhancement,photocatalytic activity,two-step solvothermal synthesis
更新于2025-09-23 15:21:01
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Preparation of Bi<sub>2</sub>WO<sub>6</sub> Powders with Micro-Carbon Spheres Acting as a Template by Refluxing Method
摘要： Firstly, we made the glucose as raw material to prepare carbon microspheres hydrothermal method. Then carbon microspheres use as a template, and Bi(NO3)3.5H2O and Na2WO4.2H2O as raw material to synthesize the Bi2WO6/carbon composite by refluxing method. Finally, Bi2WO6 samples were obtained by calcination so as to remove the template. And samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflection absorption spectroscopy (DRS). The Rhodamine B (RhB) was simulated as the sewage under the visible light to study the impact of the illumination time, calcination temperature and the amount of catalyst. The results show that Bi2WO6 synthesized by calcination at 500 oC had the best photocatalytic performance, and when samples (30 mg) was put into RhB solution (10 mg/L) and illumination for 180 min, the degradation rate could reach 92%, which demonstrated that the samples exhibit excellent visible photocatalytic performance.
关键词： template,Bi2WO6,reflux method,carbon microspheres
更新于2025-09-23 15:21:01
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Photo-induced meta-stable polar conformations in polystyrene microspheres revealed by time-resolved SHG microscopy
摘要： Photo-induced second harmonic generation (SHG) was observed in centrosymmetric polystyrene (PS) microspheres using 1064 nm, sub-nanosecond laser-pulse irradiation. The SHG signal gradually increased upon stationary laser-pulse irradiation. After stopping the irradiation, the increased SHG signal disappeared in approximately 30 min. When the PS bead was irradiated by laser pulses again, the SHG signal reappeared with similar temporal behavior, which was attributed to the probable growth and contraction of meta-stable polar conformations of PS chain segments under periodic photo-thermal stimuli.
关键词： second harmonic generation,photo-induced,polystyrene microspheres,time-resolved SHG microscopy
更新于2025-09-23 15:19:57
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Atomic Layer Deposition Assisted Encapsulation of Quantum Dot Luminescent Microspheres toward Display Applications
摘要： Quantum dots (QDs) are promising for being used in advanced displays due to their outstanding emission properties. Herein, a novel encapsulation method for QDs is reported and ultra-stable QDs@SiO2@Al2O3 luminescent microspheres (QLuMiS) are obtained by combining a sol–gel method for the intermediate SiO2 layer with a fluidized powder atomic layer deposition (ALD) for the outer Al2O3 layer. The rich hydroxyl coverage on the QDs@SiO2 surface provides abundant chemisorption sites, which are beneficial for the deposition of Al2O3 in the ALD process. Simultaneously, the water-oxygen channels in the SiO2 layer are blocked by the Al2O3 layer, which protects the QDs against deterioration. Consequently, the QLuMiS exhibit an excellent stability with 86% of the initial light conversion efficiency after 1000 h of blue light aging under a light power density of 2000 mW cm?2. Such stability is significantly better than that of QDs@Al2O3 and QDs@SiO2 samples. Moreover, under this strong irradiation aging condition with blue light, the extrapolated lifetime (L50) of QLuMiS is 4969 h, which is ten times longer than that of QDs@SiO2 and is the best record as far as is known. Finally, a prototype of a QLuMiS-based cell-phone screen with a wide color gamut of 115% NTSC is demonstrated.
关键词： luminescent microspheres,quantum dots,atomic layer deposition,encapsulation
更新于2025-09-23 15:19:57
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TiO2 Passivation Layer on ZnO Hollow Microspheres for Quantum Dots Sensitized Solar Cells with Improved Light Harvesting and Electron Collection
摘要： Light harvesting and electron recombination are essential factors that influence photovoltaic performance of quantum dots sensitized solar cells (QDSSCs). ZnO hollow microspheres (HMS) as architectures in QDSSCs are beneficial in improving light scattering, facilitating the enhancement of light harvesting efficiency. However, this advantage is greatly weakened by defects located at the surface of ZnO HMS. Therefore, we prepared a composite hollow microsphere structure consisting of ZnO HMS coated by TiO2 layer that is obtained by immersing ZnO HMS architectures in TiCl4 aqueous solution. This TiO2-passivated ZnO HMS architecture is designed to yield good light harvesting, reduced charge recombination, and longer electron lifetime. As a result, the power conversion efficiency (PCE) of QDSSC reaches to 3.16% with an optimal thickness of TiO2 passivation layer, which is much higher when compared to 1.54% for QDSSC based on bare ZnO HMS.
关键词： TiO2 passivation layer,quantum dots sensitized solar cells,ZnO hollow microspheres
更新于2025-09-23 15:19:57
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Crosslinkinga??Induced White Light Emission of Poly(Hydroxyurethane) Microspheres for White LEDs
摘要： Nonconjugated luminescent polymers with white light emission are promising for a wide range of applications in display and lighting devices, but their preparation remains a big challenge. Herein, a white-light-emitting nonconjugated poly(hydroxyurethane) microsphere (PHUM) synthesized from the crosslinking reaction of trimethylolpropane tri(cyclic carbonate) ether and 1,6-hexanediamine in chloroform is reported. The resultant PHUMs possess uniform sizes ranging from 12.6 to 21.5 μm. It is proposed that a high crosslinking degree and various hydrogen-bonding strengths induce the formation of carbamate clusters with different sizes and broad distributions, which result in a broad emission spectrum. The cluster-size distribution effect leads to multiple n–π* transitions from various carbamate clusters via through-space conjugation of carbamates, realizing white light emission. In addition, the application of PHUMs as single phosphor combined with a 365 nm UV chip is also demonstrated, with which a white-light-emitting diode with a high color rendering index of up to 95 is obtained. This work confirms that crosslinking can induce multiple emissions, which provides a new clusteroluminescence and polymerization-induced emission system for tunable luminescence emission.
关键词： through-space conjugation,light-emitting diodes,poly(hydroxyurethane) microspheres,clusteroluminescence,H-bonding
更新于2025-09-23 15:19:57