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Unique 1D/3D K <sub/>2</sub> Ti <sub/>6</sub> O <sub/>13</sub> /TiO <sub/>2</sub> micro-nano heteroarchitectures: controlled hydrothermal crystal growth and enhanced photocatalytic performance for water purification
摘要： Semiconductor photocatalysis towards pollutant degradation driven by solar energy is regarded as a promising technology to solve global energy and environmental problems. In this work, three-dimensional (3D) TiO2 microflowers (MFs) were hybridized with one-dimensional (1D) K2Ti6O13 nanobelts (NBs) to construct novel hierarchical Ti–O-based micro-nano heteroarchitectures (HAs) using a controlled hydrothermal route. The well-developed TiO2 MFs were featured with their petals consisting of several 1D nanostructures with the width of around 100–200 nm. Particularly, the crystal growth mechanism of the unique 1D/3D K2Ti6O13/TiO2 HAs was proposed based on the time-dependent experiments combined with structural and morphological characterizations. Unexpectedly, the optimized K2Ti6O13/TiO2 composites exhibited much higher photocatalytic performance for the degradation of organic dyes and antibiotics under simulated sunlight irradiation, which was more than 2-folds higher than that of single K2Ti6O13 and TiO2 catalysts. Moreover, the photocatalytic activity of K2Ti6O13/TiO2 composites for dye degradation was higher than that of commercial P25 under visible light irradiation (λ > 400 nm). Apart from the advantages of hierarchical micro-nano HAs in improving light adsorption and surface area, the enhanced photocatalytic properties could be particularly attributed to the formation of K2Ti6O13/TiO2 heterojunctions that offered available interfacial channels for charge transfer and separation, as proved by the photoluminescence and photoelectrochemical measurements. Furthermore, good stability and long-term durability of the composite photocatalysts were also determined by cycling tests, mainly resulting from the tightly combined K2Ti6O13/TiO2 heterostructures. This work can be extended to design other hierarchical TiO2-based micro-nano hybrids with superior photocatalytic properties for environmental purification and solar energy conversion.
关键词： photocatalytic performance,K2Ti6O13 nanobelts,water purification,Semiconductor photocatalysis,TiO2 microflowers,micro-nano heteroarchitectures,hydrothermal route
更新于2025-09-16 10:30:52
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The fabrication of a biomass carbon quantum dot-Bi <sub/>2</sub> WO <sub/>6</sub> hybrid photocatalyst with high performance for antibiotic degradation
摘要： A novel biomass carbon quantum dots@Bi2WO6 (BC-QDs@Bi2WO6) photocatalyst with uniform dispersivity was prepared via a dialysis-assisted hydrothermal process. Multiple techniques including HR-TEM, XPS, UV-Vis, PL, photocurrent analysis, and electrochemical impedance spectroscopy were employed to investigate the morphology and structures as well as the optical and electronic properties of the as-prepared samples. The photocatalytic activity of BC-QDs@Bi2WO6 was assessed by the degradation of antibiotics (tetracycline, ciprofloxacin, and gatifloxacin). The improved photocatalytic activity was attributed to the quantum effect of BC-QDs, which acted as the light harvesting center, electron reservoir, and reaction center for degrading the pollutants. Furthermore, a plausible mechanism for photocatalysis was put forward according to the ESR and quenching experiments. The present work can have significant advantages in the construction of biomass carbon-based photocatalysts in pollutant degradation and improved light utilization.
关键词： Bi2WO6,dialysis-assisted hydrothermal process,photocatalyst,biomass carbon quantum dots,antibiotic degradation
更新于2025-09-16 10:30:52
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The synthesis of Co <sub/>x</sub> Ni <sub/>1?x</sub> Fe <sub/>2</sub> O <sub/>4</sub> /multi-walled carbon nanotube nanocomposites and their photocatalytic performance
摘要： A series of CoxNi1?xFe2O4/multi-walled carbon nanotube (CoxNi1?xFe2O4/MWCNTs) nanocomposites as photocatalysts were successfully synthesized, where CoxNi1?xFe2O4 was synthesized via a one-step hydrothermal approach. Simultaneously, methylene blue (MB) was used as the research object to investigate the catalytic effect of the catalyst in the presence of hydrogen peroxide (H2O2). The results showed that all the photocatalysts exhibited enhanced catalytic activity compared to pure ferrite. In addition, compared with the other photocatalysts, the reaction time was greatly shortened a significantly higher removal rate was achieved using 3-CNF/MWCNTs. There was no significant decrease in photodegradation efficiency after three catalytic cycles, suggesting that CoxNi1?xFe2O4/MWCNTs are recyclable photocatalysts for wastewater treatment. Our results indicate that the CoxNi1?xFe2O4/MWCNT composite can be effectively applied for the removal of organic pollutants as a novel photocatalyst.
关键词： methylene blue,photocatalysts,hydrothermal approach,wastewater treatment,multi-walled carbon nanotube,hydrogen peroxide,CoxNi1?xFe2O4
更新于2025-09-16 10:30:52
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One-Pot Synthesis of Flower like FeS2 as Counter Electrode for Quantum Dot Sensitized Solar Cells
摘要： Counter electrodes plays significant role in electron transport in photovoltaics and an ideal counter electrode should have high electrocatalytic activity, cost effective, high performance stability. With this concern, an easy fabrication process is also necessary for quantum dot-sensitized solar cells (QDSSCs). Iron disulfide (FeS2) is an earth-abundant, non toxic and low-cost material and We report a facile one-pot hydrothermal method for the growth of flower like FeS2, which is used as a high efficient counter electrode for QDSSCs. FESEM images show the flower like morphology and XRD pattern confirms the formation of iron pyrite phase. UV-visible absorption spectrum showed absorption in the visible region. QDSSC with FeS2 nanoflower as counter electrode exhibited a power conversion efficiency of 1.174 % with a Voc of 1.368.
关键词： Counter electrode,FeS2,Nanoflower,Hydrothermal,QDSSCs
更新于2025-09-16 10:30:52
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Photoluminescence and Photodetecting Properties of the Hydrothermally Synthesized Nitrogen-Doped Carbon Quantum Dots
摘要： Carbon quantum dots (CQDs) have attracted more and more attention as the representative of a new generation of photoluminescence (PL) and photodetecting materials due to their unique optoelectrical properties. However, the formation mechanism of the CQDs as well as the origin of PL from the CQDs are still open questions to be issued. Here, we report our recent progress on the synthesis of the nitrogen-doped carbon quantum dots (N-CQDs) with a high photoluminescence quantum yield (PLQY) of 97.4% by adjusting the hydrothermal synthesis parameters with the citric acid (CA) and ethylenediamine (EDA) as the precursors. The detailed structure and properties indicate that N-CQDs is synthesized by dehydration, condensation, and carbonization, and the PL is attributed to the synergistic effect of the carbogenic core and the surface/molecule state. With above progress, an all-carbon-based ultra-violet (UV) photodetector is fabricated based on the N-CQDs/graphene hybrid composites, which exhibits significant negative photoconductivity phenomenon. A maximal negative responsivity up to 2.5×104 AW-1 at UV region has been observed, which was attributed to the two competing mechanisms. One is the oxygen adsorption and photo-desorption induced negative photoresponse, while the other is the surface defects in N-CQDs related positive photoconducting. Our work reveals the mechanisms driven force behind positive and the negative photoconducance phenomenon of photodetectors based on CQDs, which not only contributes to the further understanding of the fluorescent and photoresponse mechanisms of CQDs, and promotes the application potential of CQDs in the field of photodetection and nano-optoelectronic sensors.
关键词： Photodetecting,Nitrogen-doped,Hydrothermal synthesis,Photoluminescence,Carbon quantum dots
更新于2025-09-16 10:30:52
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Synthesis of carbon quantum dots in a Nafion matrix: Precursor effect on the ion transport properties
摘要： Carbon quantum dots have been prepared in a Nafion? matrix via the hydrothermal treatment of organic precursors, and the swelling and ion transport properties of the prepared composite materials have been characterized.
关键词： Nafion matrix,ion transport properties,carbon quantum dots,hydrothermal treatment
更新于2025-09-16 10:30:52
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Nitrogen plasma treatment of ZnO and TiO2 nanowire arrays for polymer photovoltaic applications
摘要： This work reports on a simple, yet unique approach to improving the opto-electronic properties of vertically-aligned arrays of rutile TiO2 and Wurzite ZnO nanowires by means of controlled nitrogen doping during exposure to highly kinetic radio-frequency generated N2 plasma radicals. Morphologically, the plasma treatment causes a distortion of the vertical alignment of the nanowires due to a dissociation of the weak Van der Waals force clustering the nanowires. Optical spectroscopy show that plasma treatment increases the light transmission of TiO2 arrays from 48% to 90%, with the ZnO arrays exhibiting an increase from 70% to 90% in the visible to UV range. The as-synthesized TiO2 array has an indirect band gap of 3.13 eV, which reduces to 3.03 eV after N2 treatment, with the ZnO equivalent decreasing from 3.20 to 3.17 eV post plasma exposure. A study of the 3d transition metal near edge fine structure of both Ti and Zn show that the N2 plasma treatment of the nanowires results in nitrogen doping of both TiO2 and ZnO lattices; this is confirmed by scanning transmission electron microscopy coupled with energy dispersive spectroscopy x-ray maps collected of single nanowires, which show a clear distribution of nitrogen throughout the metal-oxide. Application of these structures in P3HT:PCBM polymer blends shows progressive improvement in the photoluminescence quenching of the photoactive layer when incorporating both undoped and nitrogen-doped nanowires.
关键词： Electron energy loss spectroscopy,RF plasma nitrogen doping,One-dimensional nanowire arrays,Hydrothermal synthesis
更新于2025-09-16 10:30:52
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Controlled hydrothermal synthesis of different sizes of BaTiO<sub>3</sub> nano-particles for microwave absorption
摘要： Different sizes of barium titanate (BaTiO3) nano-particles were synthesized from precursor H2Ti3O7 nanotubes through facile hydrothermal synthesis by using EtOH/H2O as mixing solvent. Field-emission scanning electron microscopy (FESEM) was mainly used to investigate the effects of solution alkalinity, polarity, and hydrothermal temperature on the size and morphology evolution of BaTiO3 nanoparticles. The results indicate that the presence of strong alkalinity improved the size evenness of BaTiO3 nanoparticles possibly because of the re-dissolution and re-precipitation of TiO3 2- ions. As for the reason, the addition of EtOH could lower the polarity of hydrothermal medium and make the medium reach the supersaturation more easily, thus limiting the size growth of BaTiO3 particles. In addition, the presence of EtOH led to easier formation of BaTiO3 nanoparticles even at mild hydrothermal temperature, but the particle size was limited even though the temperature was much increased. This is possibly due to lowered interfacial activity in the presence of EtOH. By adjusting solution alkalinity, EtOH/H2O volume ratios, and hydrothermal temperature, BaTiO3 nanoparticles with the average sizes of approximately 21, 53, 104, 284, and 512 nm, were obtained, and more different and controlled nano-sizes can be expected by further hydrothermal adjustment. In the end, microwave absorption evaluation indicated that the decreased size of the BaTiO3 particles enhanced the reflection loss. One possible reason is that the decreased nano-size led to the increased specific surface area of the BaTiO3 nanoparticles.
关键词： Hydrothermal synthesis,Barium titanate,Polarity,Temperature,Microwave absorption,Adjustable nano-size
更新于2025-09-16 10:30:52
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Inserting dome shape microstructure for enhancement of ultraviolet photodetector performance of n-ZnO nanorods/p-Si heterojunction
摘要： A mixed intermediate layer of silica and zinc oxide (SZO) with architecturally dome-shaped microstructure is fabricated and characterized by combining a hydrothermal method and a plasma-enhanced chemical vapor deposition technique. Our results demonstrated that 200 (cid:1)C was an optimum deposition temperature for dome shape architecture SZO layer, acting as an antire?ection layer in the ultraviolet range and buffer layer for growth ZnO nanorods (NRs) arrays. Consequently, at 2.0 V reverse bias, the photo-to-dark current ratio measured with an p-Si/n-ZnONRs photodiode employing the dome-shaped SZO layer is improved by almost three orders of magnitude in the ultraviolet range as compared to that under visible-light illumination.
关键词： ZnO nanorods,Hydrothermal growth,Plasma-enhanced chemical vapor deposition,Photodiodes
更新于2025-09-16 10:30:52
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Ni3S2@MWCNTs films for effective counter electrodes of dye-sensitized solar cells
摘要： Composite films nickel sulfide (Ni3S2) nanoparticles were grown on multiwall carbon nanotubes (MWCNTs) and in situ coated onto conducting glass substrates by the hydrothermal process at 170 °C. These Ni3S2@MWCNTs films were applied for counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). In this work, nanostructure, crystalline structure, electrochemical activities and electron-charge transfer resistance of CEs were studied. In addition, the effective surface areas of CEs were analyzed and discussed as well. The power conversion efficiency (PCE) enhancement of up to 7.48%, compared with that of Ni3S2-DSSC, was demonstrated for a Ni3S2@MWCNTs DSSC.
关键词： Counter electrode,Ni3S2,Dye-sensitized solar cell,Hydrothermal method,Multiwall carbon nanotubes
更新于2025-09-16 10:30:52