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Visible light-driven photoelectrocatalytic degradation of Acid Yellow 17 using Sn3O4 flower-like thin films supported on Ti substrate (Sn3O4/TiO2/Ti)
摘要： This article reports a new method for preparing mixed valence tin oxide (Sn3O4) flower-like nanostructures using a microwave-assisted route. Thin-film Sn3O4/TiO2/Ti electrodes demonstrated highly efficient visible light driven photocatalytic degradation of monoazo acid yellow 17 (AY17) dye, reaching 95% color removal after 60 min at pH 2. Moreover, under low bias potential (0.5 V), the photoelectrocatalytic efficiency increased to 97% color removal and 83% removal of total organic carbon at a kinetic rate almost 3 times higher than in photocatalysis. Liquid chromatography mass spectrometry was used to identify intermediate formation, and oxidation performance was proposed for photocatalytic and photoelectrocatalytic degradation with no organics identified after 120 min of treatment. The results indicate that Sn3O4/TiO2/Ti photoelectrodes offer a simple, green method for wastewater treatment employing visible light source.
关键词： Dye degradation,Photoelectrocatalysis,Microwave-assisted hydrothermal synthesis,Sn3O4,Visible-light photocatalysis
更新于2025-11-19 16:56:35
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Synthesis of Mn doped ZnO nanopowders by MW-HTS and its structural, morphological and optical characteristics
摘要： In this study, undoped and Mn doped ZnO nanopowders were synthesized by using the microwave assisted hydrothermal (MW-HTS) method. Doping ratio of Mn in the ZnO was set to 1, 5 and 10%. The effect of Mn concentration on the structural and morphological properties of ZnO nanopowders was investigated using XRD, SEM, XPS and FTIR. XRD results showed that the nanopowders have hexagonal wurtzite structure. The lattice parameters increased with increasing Mn incorporation. SEM images showed that all the samples were formed in nanorod structure and the average diameter of the rods decreased with the Mn concentration. XPS results veri?ed the presence of Mn as a doping element into ZnO crystal lattice and the oxidation states of Mn and Zn. The chemical interactions of ZnO and ZnO:Mn nanopowders were determined for using FTIR spectrum.
关键词： FTIR,Mn doped ZnO,XPS,Microwave assisted hydrothermal,Nanorods
更新于2025-09-23 15:22:29
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Microwave-assisted hydrothermal synthesis of BiOCl/Bi2WO6 nanocomposites for the enhancement of photocatalytic efficiency
摘要： In this research, BiOCl/Bi2WO6 nanocomposites were successfully synthesized by a microwave-assisted hydrothermal method. Phase, morphology and optical properties of the as-synthesized products were investigated by X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy and photoluminescence (PL) spectroscopy. The as-synthesized products were BiOCl/Bi2WO6 nanocomposites composed of Bi2WO6 microflowers mixed with BiOCl nanoplates. The photocatalytic properties of BiOCl/Bi2WO6 nanocomposites were estimated through photodegradation of rhodamine B and salicylic acid as organic models in wastewater. The 80 wt% BiOCl/Bi2WO6 nanocomposites presented the highest photocatalytic efficiency and were certified for the lowest photonic emission by PL analysis. There was a trivial loss of activity even after four re-cycle tests. A mechanism for photocatalysis by BiOCl/Bi2WO6 nanocomposites was also proposed.
关键词： BiOCl/Bi2WO6 nanocomposites,Photocatalysis,Microwave-assisted hydrothermal synthesis
更新于2025-09-23 15:22:29
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Photocatalytic degradation of 4-chlorophenol with the use of FTO/TiO2/SrTiO3 composite prepared by microwave-assisted hydrothermal method
摘要： Microwave-assisted hydrothermal method was applied to obtain SrTiO3 photocatalyst by transformation of a thin TiO2 layer deposited on the conducting solid substrate (FTO-glass) via dissolution-precipitation reaction in alkaline solution. The influence of Sr2+ ions concentration on crystallinity, composition as well as photoelectrochemical and photocatalytic properties of the resultant materials was investigated. The XRD studies indicated the presence of some amount of co-deposited SrSiO3 due to reaction of metasilicates released from the glass substrate (not covered with FTO film). However, the process of glass dissolution was substantially prevented by protection of the back side of the sample with a Teflon tape. The best activity in photodecomposition of 4-chlorophenol under irradiation with 365 nm diode was obtained for FTO/TiO2/SrTiO3 composite fabricated in 6 h synthesis in the solution containing 0.1 M Sr(NO3)2, at temperature of 180 °C. The photoelectrochemical properties of the composites and FTO/TiO2 electrode were studied in the solution of Na2SO4 under illumination with a xenon lamp. The increased photocurrent density and longer electron lifetime for the hybrid system in comparison to those of TiO2 was discussed in terms of suppressed recombination rate due to formation of TiO2/SrTiO3 interface. It was also found that the side product, SrSiO3, reveals an excellent adsorption properties with respect to methylene blue and therefore, the system SrTiO3/TiO2/FTO/glass/SrSiO3 may be used as bifunctional composite for adsorption and photocatalysis.
关键词： 4-Chlorophenol photodecomposition,Photocatalysis,SrSiO3,Photoelectrochemical properties,Microwave-assisted hydrothermal synthesis,TiO2/SrTiO3,Electron lifetime
更新于2025-09-23 15:21:21
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The Enhanced NO2 sensing properties of SnO2 nanoparticles/reduced graphene oxide composite
摘要： Multiple techniques were utilized to characterize the structure and morphology of the SnO2/reduced graphene oxide (rGO) composite, in which the composite was prepared by a facile one-pot microwave-assisted hydrothermal method. As a result, SnO2 nanoparticles with diameters of 3-5 nm were anchored uniformly on both sides of the rGO sheets. Meanwhile, a series of resistive-type gas sensors based on SnO2/rGO composite and pure SnO2 were fabricated and tested for analyzing the effects on introducing rGO. The results revealed that, the composite exhibited obviously enhanced gas sensing properties towards NO2 with high response, fast response and recovery speed, and good selectivity and reproducibility. At 75°C, the response of the composite to 350 ppb NO2 was about 6.6 times of that to pure SnO2. In addition, the response and recovery time of the sensor was greatly reduced from 39.2/54.7 to 6.5/1 minutes, and the detecting limit of the sensor was even as low as 50 ppb. Provided with the enlarged surface area and local p-n heterojunctions, the synergistic effect of SnO2 nanoparticles and rGO contributed to the enhanced gas sensing properties of SnO2/rGO composite.
关键词： SnO2,Graphene,Heterojunctions,Microwave-assisted hydrothermal,Gas sensor
更新于2025-09-23 15:21:21
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Femtosecond-laser-irradiation-induced structural organization and crystallinity of Bi2WO6
摘要： controlling the structural organization and crystallinity of functional oxides is key to enhancing their performance in technological applications. in this work, we report a strong enhancement of the structural organization and crystallinity of Bi2Wo6 samples synthetized by a microwave-assisted hydrothermal method after exposing them to femtosecond laser irradiation. X-ray diffraction, UV-vis and Raman spectroscopies, photoluminescence emissions, energy dispersive spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy were employed to characterize the as-synthetized samples. To complement and rationalize the experimental results, first-principles calculations were employed to study the effects of femtosecond laser irradiation. Structural and electronic effects induced by femtosecond laser irradiation enhance the long-range crystallinity while decreasing the free carrier density, as it takes place in the amorphous and liquid states. these effects can be considered a clear cut case of surface-enhanced Raman scattering.
关键词： structural organization,Bi2WO6,femtosecond laser irradiation,crystallinity,microwave-assisted hydrothermal method
更新于2025-09-23 15:19:57
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A Facile Microwave-Assisted Hydrothermal Synthesis of Graphene Quantum Dots for Organic Solar Cell Efficiency Improvement
摘要： Carbon-based nanomaterials have successively remained at the forefront of different research fields and applications for years. Understanding of low-dimension carbon material family (CNT, fullerenes, graphene, and graphene quantum dots) has arrived at a certain extension. In this report, graphene quantum dots were synthesized from graphene oxide with a microwave-assisted hydrothermal method. Compared with conventional time-consuming hydrothermal routes, this novel method requires a much shorter time, around ten minutes. Successful formation of quantum dots derived from graphene sheets was verified with microscopic and spectroscopic characterization. Nanoparticles present a diameter of about 2-8 nm, blue emission under ultraviolet excitation, and good dispersion in polar solvents and can be collected in powder form. The synthesized graphene quantum dots were utilized as a hole transport layer in organic solar cells to enhance the cell quantum efficiency. Such quantum dots possess energy levels (Ec and Ev) relevant to HOMO and LUMO levels of conductive polymers. Mixing P3HT:PCBM polymer and graphene quantum dots of sufficient extent notably helps reduce potential difference at interfaces of the two materials. Overall efficiency consequently advances to 1.43%, an increase of more than 44% compared with pristine cells (0.99%).
关键词： microwave-assisted hydrothermal synthesis,organic solar cells,graphene quantum dots,efficiency improvement
更新于2025-09-23 15:19:57
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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia, Romania (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Substrate Effect on the Morphology and Optical Properties of ZnO Nanorods Layers Grown by Microwave-Assisted Hydrothermal Method
摘要： The substrate effect on the morphology and optical properties of zinc oxide nanorods synthesized by microwave-assisted hydrothermal method have been investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-VIS-NIR optical absorption and reflecting spectroscopy. The band gap energy of the investigated samples was calculated from absorbance spectra in the (200-1100) nm wavelengths range.
关键词： optical properties,ZnO nanorods,band gap energy,microwave-assisted hydrothermal synthesis,morphology
更新于2025-09-23 15:19:57
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Rapid and green synthesis of fluorescent carbon dots from starch for white light-emitting diodes
摘要： A simple and green synthesis of fluorescent carbon dots (CDs) was achieved by a microwave-assisted hydrothermal method using potato starch as the carbon source. CDs with a maximum quantum yield of 2.46% were prepared by hydrothermal treatment of a 1 mg/mL starch solution at 220 oC for 30 min. Nitrogen doped CDs (N-CDs) were obtained under the same conditions using starch and ethylenediamine as the carbon and nitrogen sources, respectively, and their quantum yield was twice that of the undoped CDs. Both the CDs and N-CDs exhibit excellent water solubility and good thermal stability, emit blue fluorescence under UV light, but the fluorescent intensity of the latter is obviously higher than that of the former. Two white light-emitting diodes using the CD/starch composite and N-CDs as the phosphors emit yellowish white light and white light, respectively with xy coordinates of (0.38, 0.45) and (0.33, 0.35) in the Chromaticity Diagram of the Commission Internationale de L'Eclairage, suggesting that they have great potential application in optoelectronic devices.
关键词： Fluorescent carbon dots,Nitrogen doping,Light-emitting diodes,Microwave-assisted hydrothermal,Starch
更新于2025-09-16 10:30:52
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Graphene quantum dot vertical cavity surface emitting lasers
摘要： Nonzero-bandgap graphene quantum dots (GQDs) are novel optical gain materials promising for solution-processed light sources with high cost efficiency and device performance. To date, there have only been a few reports on the realization of GQDs-based lasers. Herein, we demonstrate for the first time room-temperature lasing emission with green gamut from GQDs in a vertical optical cavity composed of Ta2O5/SiO2 dielectric distributed Bragg reflectors (DBRs). The lasing is enabled by the unique design of the DBR which not only provides a wide stopband spectrally overlapping with the emission of the GQDs but also allows high transmittance of optical excitation in the UV-light region. This demonstration is a clear evidence of the use of GQDs as optical gain materials and represents an important step forward toward their potential applications in wide-gamut laser displays and projectors.
关键词： Vertical Cavity Surface Emitting Laser,Graphene Quantum Dots,Green Gap,Microwave-Assisted Hydrothermal Method,Distributed Bragg Reflectors (DBRs)
更新于2025-09-11 14:15:04