- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Efficient near-infrared photocatalysts based on NaYF4:Yb3+,Tm3+@NaYF4:Yb3+,Nd3+@TiO2 core@shell nanoparticles
摘要： In this work, we fabricated NaYF4:Yb3+,Tm3+@NaYF4:Yb3+,Nd3+@TiO2 (Tm@Nd@TiO2) core@shell nanoparticles and investigated their near-infrared (NIR) photocatalytic activities. Comparing to traditional TiO2 based upconversion (UC) photocatalysts (i.e., NaYF4:Yb3+,Tm3+@TiO2, named Tm@TiO2), Tm@Nd@TiO2 exhibits enhanced photocatalytic activity under NIR light irradiation. The photocatalytic activity of Tm@Nd@TiO2 under 980, 808, and 980+808 nm laser irradiation is 4.40, 5.84, and 9.83 times as high as that of Tm@TiO2 under only 980 nm irradiation, respectively. The ethylene degradation rate of Tm@Nd@TiO2 under 980+808 nm laser irradiation is 6.4 times as that of Tm@TiO2. The photocatalytic activity of Tm@Nd@TiO2 under visible+NIR irradiation is even comparable with (~2/3) that under UV light irradiation during Rhodamine B (RhB) degradation. The enhanced photocatalytic activity of Tm@Nd@TiO2 can be attributed to the stronger light absorption in NIR region ascribed to Nd3+, lower water absorption and the enhanced UC emission of Tm@Nd with unique core@shell nanostructures. This work can provide a possible route to improve the NIR photocatalytic activity and stimulate the applications in many other fields.
关键词： upconversion,near-infrared irradiation,photocatalyst,core@shell structure
更新于2025-09-23 15:23:52
-
Atomic-scale simulations of ideal strength and deformation mechanism in β-SiC under H/He irradiation
摘要： We ?rstly investigated the mechanical responses of β-SiC to the tensile and shear strains under H/He irradiation using density functional theory, with a speci?c focus on the atomistic mechanism of deformation and fracture. The results revealed that the e?ect of introducing H/He on ideal strengths of tension and shear is limited, due to the strong sp3 bonds of Si-C. However, somehow large disparity in failure was discovered after introducing H/He. Under the tension, all Si-C bonds along the tensile direction are synchronously broken, causing cubic-to-graphitic transformation in the perfect β-SiC, in contrast to the asynchronous breakage of Si-C bonds in the H/He-doping systems. Under the shear, H- and He-doping systems display individual cleavage-like modes of lattice instability, respectively, whereas structural transformation by re-bonding new Si-C bonds is responsible for the failure in the perfect β-SiC. The cleavage-like modes were discussed, combining a detailed analysis of electronic structure. The mechanical response to H/He irradiation distinguishes β-SiC from conventional metals presently applied in nuclear industry. The study may provide a clue for new design strategy of irradiation-tolerant materials for energy applications.
关键词： Ideal strength,H/He irradiation,Deformation mechanism,β-SiC ceramic
更新于2025-09-23 15:23:52
-
Construction of Pt-decorated g-C3N4/Bi2WO6 Z-scheme composite with superior solar photocatalytic activity toward rhodamine B degradation
摘要： Highly efficient visible-light-driven Pt-decorated g-C3N4/Bi2WO6 hybrid photocatalysts were successfully prepared via a photodeposition method. The microstructures and optical properties of the prepared samples were characterized by transient photocurrent experiments, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-vis diffused reflectance spectra (DRS), photoluminescence (PL), electron spin resonance (ESR) spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. FESEM and TEM images show that metallic Pt particles disperse on the surface of g-C3N4/Bi2WO6 hybrid. Pt-decorated g-C3N4/Bi2WO6 compsites exhibited excellent DRS attribute to the surface plasmonic resonance (SPR) of Pt particles and g-C3N4/Bi2WO6. The PL results verified that the suitable band potential of g-C3N4 and Bi2WO6 for construction of Z-type photocatalytic system. In the photocatalytic experiment, results showed that Pt(1%)-g-C3N4/Bi2WO6 photocatalysts displayed higher photocatalytic activity than either pure g-C3N4 or Bi2WO6 for the degradation of Rhodamine B (RhB). Additionally, the free-radical trapping experiments and ESR disclose that the hole (h+), superoxide radical (·O2-) and hydroxyl radical (·OH) acted as reactive species. Based on above, a possible plasmonic Z-scheme mechanism for organics degradation over Pt-decorated g-C3N4/Bi2WO6 was proposed.
关键词： g-C3N4/Bi2WO6,Visible light irradiation,Z-scheme heterojunction,Pt-decorated
更新于2025-09-23 15:23:52
-
Performance enhancement of ZnO nanorod-based enzymatic glucose sensor via reduced graphene oxide deposition and UV irradiation
摘要： This paper reports the performance enhancement of a ZnO nanorod-based enzymatic glucose sensor with reduced graphene oxide (rGO) introduced between the ZnO nanorods and indium tin oxide (ITO) electrode and then stimulated under UV irradiation. The electrochemical characterization indicates that the rGO not only facilitates electron transfer through the ZnO nanorods to the ITO electrode but also inhibits the fast recombination of the photo-generated electrons and holes. The UV irradiation stimulates holes in the valence band of the ZnO nanorods, which as oxidants enhance the catalytic activity of the glucose oxidase (GOx) towards glucose. The rGO increases the sensitivity of the ZnO nanorod-based glucose sensor by 1.6 times and decreases the detection limit by 2.3 times. Together with the rGO, the UV irradiation further increases the sensitivity by 1.7 times and diminishes the detection limit by 2 times. Moreover, the as-prepared glucose sensors exhibit excellent selectivity to urea, uric acid, and ascorbic acid, and can reliably determine the glucose concentration in a serum sample. The results have the potential to improve the performance of other enzymatic biosensors.
关键词： Glucose sensor,ZnO nanorod,UV irradiation,Graphene,Electrochemical test
更新于2025-09-23 15:23:52
-
Numerical and outdoor real time experimental investigation of performance of PCM based PVT system
摘要： Photovoltaic power generation is a suitable option to counter depleting and environmentally hazardous fossil fuels. However, increased cell temperature of the photovoltaic module reduces the electrical performance. Therefore, for enhancing the electrical performance as well as to obtain the useful thermal, a combined photovoltaic thermal system is suitable technology. Furthermore, the addition of phase change materials into photovoltaic thermal systems adds more dual benefits in terms of cooling of PV cell as well as heat storage. Hence, there are still issues to transfer heat from the system efficiently, which cause lower performance of PVT and PVT-PCM systems. In this paper, the aluminium material of thermal collector is used by introducing a novel design to enhance heat transfer performance, which is assembled in PVT and PVT-PCM systems. Experimental validation is carried out for the 3D FEM-based numerical analysis with COMSOL Multiphysics? at 200 W/m2 to 1000 W/m2 varying irradiation levels while keeping mass flow rate fixed at 0.5LPM and inlet water temperature at 32 °C. The experiment is carried out at outdoor free weather conditions with passive cooling of the module by an overhead water tank scheme. A good agreement in numerical and experimental results is achieved through experimental validation. Cell temperature reduction of 12.6 °C and 10.3 °C is achieved from the PV module in case of the PVT-PCM system. The highest value of the electrical efficiency achieved is 13.72 13.56% for PV and 13.85 and 13.74% for PVT numerically and experimentally respectively. Similarly, for PVT-PCM, electrical efficiency is achieved as 13.98 and 13.87% numerically and experimentally respectively. In the case of the PVT system, electrical performance is improved as 6.2 and 4.8% and for PVT-PCM, it is improved as 7.2 and 7.6% for numerically and experimentally respectively.
关键词： PCM,PV/T,Performance,Solar irradiation
更新于2025-09-23 15:23:52
-
Effect of Electron Irradiation on the Transport and Field Emission Properties of Few-Layer MoS <sub/>2</sub> Field-Effect Transistors
摘要： Electrical characterization of few-layer MoS2 based field effect transistors with Ti/Au electrodes is performed in the vacuum chamber of a scanning electron microscope in order to study the effects of electron beam irradiation on the transport properties of the device. A negative threshold voltage shift and a carrier mobility enhancement is observed and explained in terms of positive charges trapped in the SiO2 gate oxide, during the irradiation. The transistor channel current is increased up to three order of magnitudes after the exposure to an irradiation dose of 100e-/nm2. Finally, a complete field emission characterization of the MoS2 flake, achieving emission stability for several hours and a minimum turn-on field of ≈ 20 V/μm with a field enhancement factor of about 500 at anode-cathode distance of ~1.5 μm, demonstrates the suitability of few-layer MoS2 as two-dimensional emitting surface for cold-cathode applications.
关键词： electron beam irradiation,2D materials,field emission,molybdenum disulfide,field effect transistors
更新于2025-09-23 15:23:52
-
Effect of microwave irradiation on the electrical and optical properties of SnO2 thin films
摘要： We report the electrical and optical characteristics of SnO2 thin films irradiated by microwaves (MWs) and grown using atomic layer deposition in a commercial MW oven operating at a frequency of 2.45 GHz. The properties of the MW-irradiated SnO2 thin films were compared with those of the as-deposited SnO2 thin films. After MW irradiation, the conductivity and transparency of the thin films were enhanced. In addition, the samples irradiated for 5 min showed optimal carrier concentration, Hall-mobility, resistivity, and transmittance values of 1.5 × 1020 cm-3, 4.6 cm2/V·s, 8 × 10-3 Ω·cm, and 95.77%, respectively. The improved properties of the MW-irradiated samples were attributed mainly to the formation of an oxygen vacancy in the SnO2 lattice during MW irradiation. Our results can be applied for the fabrication of pure SnO2-based transparent conductive oxides; these oxides are generally doped with other elements.
关键词： SnO2,Transparent Conductive Oxide,Microwave Irradiation,Electrical and Optical Properties
更新于2025-09-23 15:23:52
-
External irradiation with heavy ions of neodymium silicate apatite ceramics and glass-ceramics
摘要： This work aims at comparing the damage induced in the Nd silicate apatite ceramic (Ca2Nd8(SiO4)6O2) by medium energy (ME) and swift heavy ion (SHI) irradiations to evaluate the effects of nuclear collisions and intense electronic excitations for ME ions and SHI ions respectively. The macroscopic induced changes were studied as a function of the fluence by swelling and hardness measurements, whereas structural modifications were followed by X-ray diffraction, Raman spectroscopy and grazing incidence EXAFS (Nd L3-edge). At ME (1.9e6.75 MeV Au ions), radiation-induced amorphization occurred above 6.22 (cid:1) 1013 Au/cm2 associated with a volume expansion of about 8% and a drop of 37% in hardness. At SHI (90 MeV Xe ions or 35 MeV Ar ions), similar macroscopic and structural changes were observed. The electronic stopping power threshold of Nd silicate apatite for amorphization was assessed at about Se ? 5 keV/nm. As apatite crystals containing actinides could be present in rare-earths rich nuclear glasses, SHI irradiation with Xe (995 MeV) ions was also used to damage the Nd silicate apatite crystals dispersed in a soda-lime aluminoborosilicate simplified nuclear glass over a depth of about 60 mm, to evaluate the possible formation of cracks in the residual glass due to crystals swelling. In spite of apatite crystals amorphization under SHI irradiation in the glass-ceramics, no cracking was observed in the glassy phase even close to the biggest crystals which could be explained by strain relaxation in the glass due to plastic deformation (creep) induced by SHI ion beam.
关键词： Amorphization,Glass-ceramic,Neodymium silicate apatite,Heavy ions irradiation
更新于2025-09-23 15:23:52
-
BiF3 octahedrons: A potential natural solar light active photocatalyst for the degradation of Rhodamine B dye in aqueous phase
摘要： Herein, we report the successful synthesis of BiF3 octahedrons via facile hydrothermal process as potential solar light active catalyst for the photocatalytic degradation of Rhodamine B (RhB) dye in aqueous phase. The synthesized BiF3 octahedrons were characterized by several techniques such as X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy, UV-diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL) spectroscopy, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) techniques in order to observe the structural, morphological, optical and luminescence properties. The synthesized octahedrons possess the high density growth, pure and well-crystalline with cubic phase structure and band gap of 3.98 eV. As a potential solar light active photocatalyst, the synthesized BiF3 octahedrons exhibited ~95.7% degradation of RhB in 50 min. The effect of different process parameters such as pH and catalyst dose on the degradation of RhB was also explored. Interestingly, the synthesized BiF3 octahedrons demonstrated better photocatalytic performance compared to several commercially available photocatalysts such as TiO2 (PC-500), SnO2 and ZnS. Further, it was observed that the degradation of RhB over the prepared BiF3 octahedrons obeyed the pseudo first-order reaction kinetics with rate constant of 0.06393 min-1. The scavenger experiments verified the role of h+, e─, O2 .─, ?OH and ?OHs in the photocatalytic degradation process and a plausible photocatalytic mechanism has also been proposed.
关键词： Rhodamine B,Photocatalysis,Solar-light irradiation,BiF3 octahedrons
更新于2025-09-23 15:23:52
-
Combination of Pd loading and electron beam irradiation for superior hydrogen sensing of electrospun ZnO nanofibers
摘要： We evaluated the hydrogen gas-sensing characteristics of Pd-loaded (0.1, 0.3, 0.6, and 1 wt%) ZnO nano?bers prepared by a facile electrospinning technique and the e?ect of di?erent electron beam (e-beam) doses (50, 100, and 150 kGy) on sensing performance. The sensor loaded with 0.6 wt% Pd had the highest response to hydrogen among the Pd-loaded sensors. The sensor irradiated with 150 kGy had the high response (Ra/Rg) of 74.7–100 ppb of H2 at 350 °C. Metallization e?ects in ZnO, the formation of structural defects due to e-beam irradiation, the catalytic activity of Pd, and the presence of ZnO–Pd heterojunctions were the main factors yielding high sensitivity towards H2. The strategy of combining e-beam irradiation and Pd loading to enhance H2 sensing can be applied to realize reliable gas sensors and the widespread use of hydrogen as a green energy alternative to fossil fuels.
关键词： H2,Electron beam irradiation,Gas sensors,ZnO nano?bers,Pd nanoparticles
更新于2025-09-23 15:23:52