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Synthesis of ZnxCd1-xSe@ZnO Hollow Spheres in Different Sizes for Quantum Dots Sensitized Solar Cells Application
摘要： ZnxCd1-xSe@ZnO hollow spheres (HS) were successfully fabricated for application in quantum dot sensitized solar cells (QDSSCs) based on ZnO HS through the ion-exchange process. The sizes of the ZnxCd1-xSe@ZnO HS could be tuned from ~300 nm to ~800 nm using ZnO HS pre-synthesized by different sizes of carbonaceous spheres as templates. The photovoltaic performance of QDSSCs, especially the short-circuit current density (Jsc), experienced an obvious change when different sizes of ZnxCd1-xSe@ZnO HS are employed. The ZnxCd1-xSe@ZnO HS with an average size distribution of ~500 nm presented a better performance than the QDSSCs based on other sizes of ZnxCd1-xSe@ZnO HS. When using the mixture of ZnxCd1-xSe@ZnO HS with different sizes, the power conversion ef?ciency can be further improved. The size effect of the hollow spheres, light scattering, and composition gradient structure ZnxCd1-xSe@ZnO HS are responsible for the enhancement of the photovoltaic performance.
关键词： zinc oxide,alloyed quantum dots,sensitized solar cells,hollow spheres
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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Synthesis of hollow spheres of BiFeO3 from nitrate solutions with tartaric acid: Morphology and magnetic properties
摘要： Single-phase powders of bismuth ferrite have been synthesized for the first time by ultrasonic spray pyrolysis from nitrate solution in the presence of tartaric acid. The produced powders consist of hollow spherical agglomerates with a mean diameter of ~1 μm. The influence of tartaric acid concentration on the synthesis temperature and morphology of hollow spheres was established. The agglomerate shells have open and closed pores. The mean values of the shell thickness and the ratios of closed and open pores were estimated and their dependence on the concentration of tartaric acid was found. It was shown that the magnetic properties are determined not only by the size of nanoparticles composing the agglomerates, but also by the morphology of hollow sphere shells.
关键词： hollow spheres,morphology,magnetic properties,multiferroics,bismuth ferrite
更新于2025-09-23 15:21:21
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Magnetic Hollow Spheres Assembled from Graphene-Encapsulated Nickel Nanoparticles for Efficient Photocatalytic CO2 Reduction
摘要： The exploitation of efficient, robust, and easily recyclable catalysts is highly desirable for photochemical CO2 reduction to produce fuels and chemicals. Herein, we demonstrate the preparation of Ni@GC magnetic hollow spheres composed of metallic Ni nanoparticles surrounded by few-layered graphitic carbon (GC) for photocatalytic CO2 reduction with high efficiency. The Ni@GC hollow spheres were prepared by thermal annealing a Ni-containing metal-organic framework (Ni-MOF) under N2 atmosphere. A series of physiochemical characterizations reveal that the Ni@GC hollow spheres are successfully synthesized with large surface area and highly porous structure. In the presence of Ni-C bonding, the porous Ni@GC material can efficiently accelerate the separation and transportation of photoexcited charges, as well as improve CO2 adsorption. With the cooperation of a ruthenium photosensitizer under visible light irradiation, the Ni@GC catalyst exhibits a high CO2-to-CO conversion activity, giving a superior CO-production rate of 27 μmol h-1 (e.g., 9.0 mmol h-1 g-1). Moreover, the Ni@GC photocatalyst is highly stable and can be separated easily by a magnetic field for reuse. The possible photosensitized CO2 conversion mechanism is also proposed based on the relative energy levels of the Ni@GC catalyst and the ruthenium photosensitizer.
关键词： magnetic nanoparticles,hollow spheres,graphene,photocatalysis,CO2 reduction
更新于2025-09-16 10:30:52
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Size tunable Bi3O4Br hierarchical hollow spheres assembled with {0?0?1}-facets exposed nanosheets for robust photocatalysis against phenolic pollutants
摘要： Synthesis of three-dimensional (3D) hierarchical hollow spheres with exposed {0 0 1} active facets are of huge significance in the field of semiconductor photocatalysis. Herein, we demonstrate a facile ionic liquid-in-water (IL/W) microemulsion approach for the fabrication of Bi-rich Bi3O4Br hierarchical hollow spheres assembled with {0 0 1}-facets exposed nanosheets. The size and {0 0 1}-facets exposure ratio of Bi3O4Br hierarchical hollow spheres can be fine-tuned by adjusting the concentration of surfactant TX-100. A possible formation mechanism of Bi3O4Br hierarchical hollow spheres assembled with {0 0 1}-facets exposed nanosheets by microemulsion template and dissolution-recrystallization was proposed based on SEM and XRD results. The actual photocatalytic activity was extensively investigated by degrading multiform phenol derivatives with different substituents and substitution positions, including acetaminophen (APAP), 4-tert-butylphenol (PTBP), o-nitrophenol (ONP), methylparaben (MPB). The Bi3O4Br hierarchical hollow spheres assembled with {0 0 1}-facets exposed nanosheets not only exhibit significantly promoted visible-light photocatalytic activity, but also have robust and nonselective photooxidation ability. The photocurrent and impedance results indicated that significantly strengthened charge separation and transfer efficiency that derived from the advantages of Bi3O4Br {0 0 1} active facets and hollow structures were responsible for the high photo-activity. The study may provide some new hints on designing and developing novel 3D hierarchical hollow structures with exposing {0 0 1} active facets for heterogeneous photocatalysis.
关键词： Bi3O4Br,Photocatalysis,Phenolic pollutants,Hierarchical hollow spheres,Exposed {0 0 1} active facets
更新于2025-09-10 09:29:36
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Novel Ag/TiO <sub/>2</sub> Hierarchical Hollow Spheres Composite with Enhanced Photocatalytic Performance
摘要： Novel Ag nanoparticles and hierarchical TiO2 (Ag/TiO2) hollow spheres composite was prepared via a facile chemical deposition route and their photocatalytic performance in degradation of Rhodamine 6G (R6G) was investigated. The results show that the photocatalytic activity of Ag/TiO2 hierarchical hollow sphere composites is superior to that of pure TiO2 hollow spheres and P25, which is attributed to the unique hollow morphology with high surface area and the reduction of photoelectron–hole pair recombination in TiO2 with the introduction of Ag NPs.
关键词： Ag/TiO2,Hierarchical Hollow Spheres Composite,Photocatalysis
更新于2025-09-10 09:29:36
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Metal-Organic Framework Derived Hierarchical Co/C@V2O3 Hollow Spheres as a Thin, Lightweight and High-Efficiency Electromagnetic Wave Absorber
摘要： Developing high-efficiency electromagnetic (EM) wave absorbing materials with light weight, thin thickness and wide absorption bandwidth is highly desirable for ever-developing electronic and telecommunication devices. Herein, hierarchical metal-organic framework (MOF)-derived Co/C@V2O3 hollow spheres were designed and synthesized through a facile hydrothermal, precipitation and pyrolysis method. The composite exhibits both excellent impedance matching and light weight due to the rational combination of hollow V2O3 spheres and porous Co/C. Additionally, multiple components enable a large dielectric and magnetic loss of the composite, giving rise to enhanced EM wave absorption performance with a maximum reflection loss (RL) of -40.1 dB and a broad effective absorption bandwidth (RL < -10 dB) of 4.64 GHz at a small thickness of 1.5 mm. This work provides insights into the design of hierarchical hollow and porous composites as a thin and lightweight EM wave absorbers with efficient absorption, which can also be extended to energy storage, catalysis and sensing.
关键词： Co/C@V2O3 composites,metal-organic framework,hierarchical hollow spheres,dielectric/magnetic composites,electromagnetic wave absorption
更新于2025-09-09 09:28:46
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Oxygen vacancy‐rich anatase TiO2 hollow spheres via liquid nitrogen quenching process for enhanced photocatalytic hydrogen evolution
摘要： Development of novel methods to obtain highly active catalysts for photocatalytic hydrogen evolution is desired. This work reports a facile preannealing-quenching strategy to synthesize oxygen vacancy-rich anatase TiO2 hollow spheres. TiO2 hollow spheres are first synthesized via a versatile kinetics-controlled coating method and then subjected to high temperature preannealing followed by rapid quenching in liquid-nitrogen (-196 oC). The as-quenched samples appear light grey suggesting the presence of abundant surface oxygen vacancies, which are subsequently confirmed by the comprehensive analyses of XRD, XPS and EPR spectra. The oxygen vacancies induced by quenching process are proved to have promoted the light adsorption and inhibited the recombination of photo-induced charges for TiO2 hollow spheres, which obviously improve the photocatalytic performance of those samples. The results showed that the TiO2 hollow spheres quenched at 500 oC exhibited a robust stability and the most excellent photocatalytic performance for hydrogen evolution (413.5 μmol·h-1) over other quenched samples and it displayed 1.51 times higher performance than that of samples normally cooled at 500 oC (273.7 μmol · h-1). Herein, this liquid-nitrogen quenching strategy presented here provides an effective route for the synthesis of high-performance TiO2 for water splitting and have a promising prospect in the other application.
关键词： quenching,hollow spheres,photocatalytic hydrogen evolution,oxygen defects,titanium dioxide
更新于2025-09-04 15:30:14