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Facile synthesis of three-dimensional ZnO hierarchical microspheres composed of well-ordered nanorods by hydrothermal method
摘要： Three-dimensional (3D) ZnO hierarchical microspheres composed of well-ordered nanorods were synthesized by a facile one-step hydrothermal method without any surfactants. The effects of reaction conditions including reaction temperature, reaction time on the microstructure of hierarchical microspheres were investigated. The results demonstrated that the reaction conditions played an important role in the morphology of 3D ZnO hierarchical microspheres. A three-stage reaction mechanism of 3D ZnO hierarchical microspheres was proposed. Firstly, Zn2+ reacts with OH- and NH4+ to produce nanoparticles. Then the nanoparticles are self-assembled into nucleis. Finally is the formation and growth of the hierarchical structure on the nuclear surface. When the as-synthesized ZnO were used as the anode of the dye sensitization solar cells (DSSCs), the 3D ZnO hierarchical microspheres composed of well-ordered nanorods exhibits the best photoelectric properties, which was attributed to the increased surface area and advantageous electronic transmission path.
关键词： photoelectric properties,Hierarchical microspheres,conditions,mechanism
更新于2025-09-23 15:23:52
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Hierarchical Photonic Pigments <i>via</i> the Confined Self-Assembly of Bottlebrush Block Copolymers
摘要： Hierarchical, structurally colored materials offer a wide variety of visual effects that cannot be achieved with standard pigments or dyes. However, their fabrication requires simultaneous control over multiple length-scales. Here we introduce a robust strategy for the fabrication of hierarchical photonic pigments via the confined self-assembly of bottlebrush block copolymers within emulsified microdroplets. The bottlebrush block copolymer self-assembles into highly ordered concentric lamellae, giving rise to a near perfect photonic multi-layer in the solid-state, with reflectivity up to 100%. The reflected color can be readily tuned across the whole visible spectrum by either altering the molecular weight or by blending the bottlebrush block copolymers. Furthermore, the developed photonic pigments are responsive, with a selective and reversible color change observed upon swelling in different solvents. Our system is particularly suited for the scalable production of photonic pigments, arising from their rapid self-assembly mechanism and size-independent color.
关键词： photonic crystals,confined self-assembly,microspheres,structural colors,bottlebrush block copolymers
更新于2025-09-23 15:23:52
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Removal of tetracycline by BiOBr microspheres with oxygen vacancies: Combination of adsorption and photocatalysis
摘要： Oxygen vacancy-containing BiOBr microspheres with dual functions of adsorption-photocatalysis were synthesized by a simple solvothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance spectroscopy (EPR) and UV–vis diffuse reflectance spectroscopy (DRS). BiOBr microspheres with oxygen vacancies exhibited a higher adsorptive and photocatalytic activity for the removal of tetracycline (TC) than that of defect-deficient BiOBr microspheres. After adsorption for 30 min and visible light irradiation for 90 min, about 94 % of TC was removed by oxygen vacancy-containing BiOBr microspheres, and TC removal efficiency performed effectively in a wide pH range from 3.1 to 11.00. Almost all inorganic anions, such as Cl?, SO2?4, PO3?4, CO2?3 and NO?3, inhibited the removal of TC by BiOBr microspheres and their inhibition effects followed the order of PO3?4 > SO2?4 > CO2?3 > Cl? > NO?3. The surface hydroxyl groups had no effect on TC adsorption, and the adsorption of TC on BiOBr was mainly through the anion exchange process. The existence of oxygen vacancies facilitated the generation of superoxide radicals (O2??), which were the dominant reactive oxygen species for TC degradation in BiOBr suspension. The adsorptive and photocatalytic performance of oxygen vacancy-containing BiOBr decreased to different degrees after three cycles mainly due to the formation of surface complex.
关键词： Mechanism,Photocatalysis,Oxygen vacancy,Adsorption,BiOBr microspheres,Tetracycline
更新于2025-09-23 15:23:52
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Preparation of Functionalized SiO2 Microspheres by One Step Method
摘要： Functional silica microparticle is a kind of important inorganic non-metallic oxide with a wide range of applications in many fields due to its excellent chemical and thermal stabilities. Post modification is the most common functional method, but, low efficiency. In this paper, a new acid hydrolysis and subsequent alkaline condensation method was developed to prepare SiO2 microspheres with functional groups on surface by condensing or co-condensing functional organosilane precursors (γ-Aminopropyltriethoxysilane (APTES), γ-Mercaptopropyltriethoxysilane (MPTES) and γ-Mercaptopropyltrimethoxysilane (MPTMS) etc) with phenyltrimethoxysilane (PTMS). Series of characterization methods, such as IR, XPS and Raman, demonstrated that the surface of the as-prepared SiO2 microspheres was successfully functionalized with amine or sulfydryl groups. This method may provide a reference for one-step preparation of functional SiO2 microspheres.
关键词： Functionalized SiO2 microspheres,Condensation,One-step method
更新于2025-09-23 15:22:29
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Significant Enhancement of Hole Transport Ability in Conjugated Polymer/Fullerene Bulk Heterojunction Microspheres
摘要： Bulk heterojunction (BHJ) strategy requires morphology of wide area donor-acceptor interfaces with high charge carrier mobilities through the bicontinuous charge transporting layers. Here, we report formation of well-defined bulk heterojunction (BHJ) microspheres from regiorandom poly(hexylthiophene) (rra-PHT)/phenyl-C61-butyric acid methyl ester (PCBM) mixture by a vapor diffusion method. By electrochemical oxidation, the BHJ microsphere exhibits enhanced generation of PHT cation species due to increased hole-transport property in comparison with a solution-cast film derived from rra-PHT/PCBM mixture without microsphere morphology. Photoconductivity and electrochemical stability of the microsphere are comparable or even higher than a cast film of irregular aggregates of regioregular P3HT.
关键词： polythiophene,bulk heterojunction,microspheres,electrochemistry,fullerene
更新于2025-09-23 15:22:29
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Preparation of hollow yttrium-doped TiO<sub>2</sub> microspheres with enhanced visible-light photocatalytic activity
摘要： Using melamine-formaldehyde polymer microspheres as templates, yttrium-doped TiO2 hollow spheres (Y-TiO2HS) were successfully prepared via a sol-gel method. The as-synthesized samples were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffuse reflectance spectrum, luminescence spectrum, specific surface area (BET) analysis and porosity analysis. The results indicate that Y doping could increase the thermal stability, reduce the band gap and enhance photocatalytic activity of the TiO2. When the Y doping molar ratio was 1.5%, the Y-TiO2HS presented high surface area (62.651 m2 /g) and photocatalytic degradation rate (about 70%). The corresponding BET value and photocatalytic degradation rate of Y-TiO2HS increased by 3 times and 50%, respectively, compared with those of un-doped TiO2HS.
关键词： synthesis,yttrium doping,hollow microspheres,photocatalytic activity,TiO2
更新于2025-09-23 15:22:29
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Plasmon-Enhanced Photodegradation of Ionic Liquids with Ag Nanocubes/ZnO Microsphere Composites
摘要： Ionic liquids (ILs) have been a hot topic in the past decades because of their unique properties and promising applications in various areas. However, the toxicity of ILs and their possible risk to the environment and aquatic organisms have also been confirmed. Therefore, it is imperative to seek an efficient way to remove or degrade ILs in the polluted aqueous system. In this work, Ag nanocubes/ZnO microspheres composites have been designed, prepared, and used for the photocatalytic degradation of eight commonly used imidazolium-based ILs in aqueous solution. It is found that ZnO semiconductor photocatalyst with an Ag content of 1.12 at. % can degrade 90% of all these ILs within 7 h. The structural characterization, photoluminescence analysis, and discrete dipole approximation calculations showed that the loading of Ag nanocubes onto ZnO microspheres significantly improves the performance of ZnO for the IL degradation through hot electron transfer and electrical field enhancement. In addition, the formed intermediates in the degradation process of [C4 mim]Cl have been detected by gas chromatography?mass spectroscopy. A possible degradation mechanism is proposed and compared with those previously reported in the chemical degradation.
关键词： Photodegradation,Ionic liquids,Plasmon-enhanced,ZnO microspheres,Ag nanocubes
更新于2025-09-23 15:21:21
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Photocatalytic removal of diclofenac by Ti doped BiOI microspheres under visible light irradiation: Kinetics, mechanism, and pathways
摘要： BiOI microspheres doped with different amounts of Ti were fabricated and used to remove diclofenac (DCF) from water under visible light irradiation. The fabricated photocatalysts were well characterized. Ti doped BiOI microspheres were found to exhibit higher photocatalytic activity towards DCF under visible light compared with BiOI. Ti doping broadened the band gap of BiOI, which leads to a more negative conduction band edge and a higher reducing activity of photo-generated electrons, thus facilitates ·O2? production during photocatalysis. Among all the fabricated Ti doped BiOI microspheres, TB450 exhibited the highest DCF photocatalytic removal efficiency. Specifically, 99.2% of DCF (C0 = 10 mg L?1) was removed by TB450 (250 mg L?1) at pH 5 within 90 min under visible light irradiation. Scavenger experiments indicated that active species including h+, ·O2? and H2O2 played important roles in the photocatalytic process. The degradation pathway of DCF was elucidated by theoretical density functional theory (DFT) and by-products identification through liquid chromatograph mass spectrometer (LC-MS) analysis. DCF degradation pathway mainly included hydroxylation and the cleavage of C\N bond. DFT calculation can well interpret the degradation mechanism and the sites of DCF molecule with high radical-attack Fukui index (f0) exhibit high reactivity. Acidic condition was found to facilitate the DCF photocatalytic removal. Due to strong photo-stability, Ti doped BiOI microspheres contained good visible-light-driven (VLD) photocatalytic removal efficiency for DCF in the fourth consecutive reused cycle. Ti doped BiOI microspheres can be employed as a cost-effective and high-efficient material to efficiently degrade emerging contaminants (e.g., pharmaceutical) from wastewaters under visible light conditions.
关键词： Ti doped BiOI microspheres,Photocatalysis,Diclofenac,Reuse,Degradation pathway,DFT calculation
更新于2025-09-23 15:21:21
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Optimizing optical tweezing with directional scattering in composite microspheres
摘要： We demonstrate that achieving zero backward scattering (ZBS), i.e., the first Kerker condition, allows for optical tweezing of high-index microspheres, which cannot be trapped using standard techniques. For this purpose, we propose an alternative material platform based on composite metamaterials. By tuning the volume filling fraction of inclusions and the microsphere radius, stable trapping can be achieved provided that ZBS is combined with the condition for destructive interference between the fields reflected at the external and internal interfaces of the microsphere when located at the focal point. By using the Mie-Debye-spherical aberration theory, we also show that the ZBS condition is even more useful in realistic, standard optical tweezer setups, in which spherical aberration is unavoidable due to refraction at the interface between the glass slide and the water-filled sample. Altogether, our findings not only pave the way for possible new trapping designs and applications but also unveil the role of backscattering in the physics of optical tweezers.
关键词： Kerker condition,optical tweezing,Mie-Debye-spherical aberration theory,directional scattering,composite microspheres
更新于2025-09-23 15:21:01
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Enhanced 2???μm Mida??Infrared Laser Output from Tm <sup>3+</sup> a??Activated Glass Ceramic Microcavities
摘要： Transparent glass ceramics (GCs) consisting of an homogeneous glass phase and a well-dispersed crystal phase are considered as ideal optical gain materials potentially applied in optoelectronic devices due to the combination of facile processability of glass and the intense crystal ?eld of nanocrystals. Here, a heat-induced nanocrystal-in-glass method is employed to integrate the active ions Tm3+ into Bi2Te4O11 nanocrystals with an intense crystal ?eld to realize an enhanced microlaser output. This strategy endows the e?cient tellurate GC microcavity laser operating at ≈2 μm. Compared with the laser properties of as-prepared glass microcavities, the pump threshold (260 μW) is as low as less than a quarter and the slope e?ciency (0.0296%) is 5.5 times higher. Furthermore, by carefully engineering the heat treatment temperature and duration, the crystal size and distribution can be precisely controlled. Thus, the Rayleigh scattering loss that is detrimental to quality (Q) factor is e?ectively suppressed and the GC microcavities with high Q factors up to 105 are successfully obtained. This work provides useful insight on the development of optical functional materials and expands the practical applications of GC microcavities in various optoelectronic ?elds.
关键词： mid-infrared lasers,glass-ceramic microspheres,microcavities,whispering gallery mode
更新于2025-09-23 15:21:01