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General Synthesis of Ordered Mesoporous Rare-Earth Orthovanadate Thin Films and Their Use as Photocatalysts and Phosphors for Lighting Applications
摘要： Herein, the block copolymer templating sol-gel synthesis of a novel class of ternary oxide nanomaterials is reported. NdVO4, EuVO4, GdVO4, DyVO4, YVO4, and TmVO4 have been prepared as open mesoporous films by the dip-coating method using hydrated rare-earth nitrate salt precursors along with vanadium oxytrichloride. All materials crystallize in the tetragonal ZrSiO4-type structure with space-group I41/amd. Short-term treatment at 550 °C is found sufficient to initiate crystallization. Characterization via X-ray and electron diffraction, Raman and X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry confirms the single-phase nature and uniformity of the different orthovanadates with tailorable crystallite sizes. The integrated results from electron and atomic force microscopy, Kr-physisorption as well as in-situ and ex-situ synchrotron-based small-angle X-ray scattering reveal that the porosity persists throughout the thickness of films and the mesoscopic ordering is retained even after heating in air at 700 °C. Photobleaching experiments indicate that the sol-gel derived materials, showing an indirect band gap transition at (3.8±0.1) eV, exhibit good photocatalytic properties—the activity is highly superior to that of bulk films of the same nominal composition. Moreover, when doping GdVO4, YVO4, and solid solution GdVO4-YVO4 with trivalent rare-earth ions such as Eu3+, Dy3+, Er3+, or Tm3+ ions, the films hold promise as phosphors for lighting applications, which might pave the way toward development of (3-dimensional) intricate nanocomposites with unprecedented functionalities.
关键词： Block copolymer templating,ternary metal oxide nanostructure,photocatalyst,phosphor,sol-gel chemistry
更新于2025-11-21 10:59:37
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Shining black nanoscopic ternary zincospiroffite: A panchromatic light harvester for depollution
摘要： Nanostructured zincospiroffite (Zn2Te3O8), a promising photocatalyst for water purification and bacterial inhibition is reported for the first time. Sparkling black Zn2Te3O8 nanocrystals have been synthesized via template-free solvothermal method with minimum precursors, zinc acetate and tellurium powder, in a polymeric medium of beta-aminoethylamine. Optical and structural characterizations prove the crystalline nature and panchromatic light harvesting behavior of zincospiroffite. X-ray photoelectron spectroscopy, Raman analysis and electron paramagnetic resonance (EPR) spectroscopy provide evidence for the anion deficiency in the crystals. A 3D crystal structure derived from XRD data confirms the bonding states. Panchromatic light harvesting behavior and reactive oxygen species generation from this unexplored semiconductor help visible to near IR driven photocatalysis and unprecedently high antibacterial activity.
关键词： Zn2Te3O8,Bacterial inhibition,Photocatalyst,Ternary metal oxide
更新于2025-09-23 15:23:52
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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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A General Method: Designing a Hypocrystalline Hydroxide Intermediate to Achieve Ultrasmall and Well‐Dispersed Ternary Metal Oxide for Efficient Photovoltaic Devices
摘要： Solution-process fine metal-oxide nanoparticles are promising carrier transport layer candidates for unlocking the full potential of solution process in solar cells, due to their low cost, good stability, and favorable electrical/optical properties. However, exotic organic ligands adopted for achieving small size and monodispersion can mostly cause poor conductivity, which thus impedes their electrical application. In this work, a concept of constructing a hypocrystalline intermediate is proposed to develop a general method for synthesizing various ternary metal oxide (TMO) nanoparticles with a sub-ten-nanometer size and good dispersibility without exotic ligands. Particularly, a guideline is summarized based on the understandings about the impact of metal ion intercalation as well as water and anion coordination on the hypocrystalline intermediate. A general method based on the proposed concept is developed to successfully synthesize various sub-ten-nanometer TMO nanoparticles with excellent ability for forming high-quality (smooth and well-coverage) films. As an application example, the high-quality films are used as hole transport layers for achieving high-performance (stability and efficiency) organic/perovskite solar cells. Consequently, this work will contribute to the development of TMO for large-scale and high-performance optoelectronic devices and the concept of tailoring intermediate can leverage the fundamental understandings of synthesis strategies for other metal oxides.
关键词： ternary metal oxide nanoparticles,general method,perovskite solar cells,hypocrystalline intermediate,organic solar cells
更新于2025-09-19 17:13:59