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Spatial separation of charge carriers in Nb2O5 nanorod superstructures for enhanced photocatalytic H2 production activity
摘要： Monoclinic Nb2O5 nanorod superstructures were first synthesized by a facile yet effective hydrothermal route using Sn2Nb2O7 nanoparticles as the precursor. These unique Nb2O5 nanorod superstructures assembled by small nanorods facilitate the spatial separation of photogenerated charge carriers, thus leading to improved photocatalytic H2 production activity in methanol aqueous solution under ultraviolet light irradiation, which is about 151 times higher than that of commercial Nb2O5 powders.
关键词： H2 evolution,Niobate oxide,Nanorod,Photocatalysis,Superstructures
更新于2025-09-10 09:29:36
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Structural, Optical, and Magnetic Properties of Hydrothermally Grown Fe-Doped ZnO Nanorod Arrays on Glass Substrate
摘要： In this paper, undoped and Fe-doped ZnO nanorod arrays were grown on glass substrate by a facile hydrothermal method. Structural, optical, and magnetic properties of the prepared nanorods were investigated. Structural investigation clearly showed that the prepared nanorods had single phase wurtzite structure without any secondary phases and the prepared undoped and Fe-doped nanorods were grown vertically. The optical characterization revealed that the optical band gap of ZnO nanorods was decreased by increasing the value of Fe concentration. Furthermore, the formation of diluted magnetic semiconductor nanorod arrays was verified. The origin of room temperature ferromagnetism is explained by the bound magnetic polaron concept.
关键词： Diluted magnetic semiconductors,Bound magnetic polaron,Nanorod arrays,Fe-doped ZnO
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Conference on Semiconductor Electronics (ICSE) - Kuala Lumpur (2018.8.15-2018.8.17)] 2018 IEEE International Conference on Semiconductor Electronics (ICSE) - Facile Synthesis of N-doped ZnO Nanorod Arrays: Towards Enhancing the UV-sensing Performance
摘要： Nitrogen (N) doped zinc oxide (ZnO) nanorod arrays at different doping concentrations from 0 at.% (undoped) to 2 at.% have been prepared using sol-gel immerse method. FESEM images revealed that the average diameter increased when the concentration of N in ZnO increased. The I-V measurement displayed that 1 at.% sample possessed the lowest resistance film and exhibit the highest UV sensing performance with sensitivity of 12.9.
关键词： nanorod,Nitrogen,immersion,zinc oxide
更新于2025-09-09 09:28:46
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NH2-MIL-125(Ti)/TiO2 Nanorod Heterojunction Photoanodes for Efficient Photoelectrochemical Water Splitting
摘要： A photoactive amine-functionalized Ti metal-organic framework (MOF) (MIL(125)-NH2(Ti)) layer is uniformly coated on vertically ordered TiO2 nanorods (NRs) via a facile hydrothermal reaction, and the performance of the heterojunction photoanode in photoelectrochemical (PEC) water splitting is studied. The photocurrent density of the MIL(125)-NH2/TiO2 NRs reaches 1.63 mA/cm2 at 1.23 V vs. a reversible hydrogen electrode under AM 1.5 G simulated sunlight illumination, which is ~2.7 times higher than that of pristine TiO2 NRs. The incident photon-to-electron conversion efficiency of the MIL(125)-NH2/TiO2 NRs improves significantly at λmax = 340 nm, implying the promotion of water oxidation through efficient light absorption and charge separation. The enhancement of the PEC activity in the TiO2 NRs caused by an MIL(125)-NH2 coating is discussed in relation to the surface area and elongated configuration of the TiO2 NRs, the band gap of MIL(125)-NH2(Ti), and the type (II) heterojunction. This study demonstrates the rational design of heterojunctions between the semiconductor and the MOF, which paves the way for new facile and general approaches to achieve a high efficiency in water splitting.
关键词： TiO2 nanorod,Photoelectrochemical water splitting,Photoanode,MIL(125)-NH2,Hydrothermal reaction
更新于2025-09-09 09:28:46
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Effects of Hydrothermal Treatment Duration on Morphology of WO <sub/>3</sub> Nanostructures
摘要： Tungsten trioxide (WO3) nanostructures have been synthesized by a simple wet chemical hydrothermal method at a temperature of 120 °C using sodium tungstate (Na2WO4 · 2H2O) as precursor material. In order to study the growth mechanism of WO3 nanostructures, the time of hydrothermal treatment was varied between 1 and 48 h. The morphology and structure of the synthesized WO3 samples were characterized by scanning electron microscopy and X-ray diffraction techniques. The duration of hydrothermal treatment significantly affected the nanostructure morphology evolution due to the limited concentration of a directional capping NaCl agent during synthesis of WO3 crystals.
关键词： Nanorod,Hydrothermal Method,Tungsten Oxide
更新于2025-09-09 09:28:46
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Study of Annealing Influence on Basic Properties of Indium Tin Oxide Nanorod Films Deposited Using Glancing Angle Ion-Assisted Electron Beam Evaporation
摘要： Indium tin oxide (ITO) nanorod ?lms were deposited onto glass slides and Si wafers using ion-assisted electron beam evaporation with a glancing angle deposition technique. The annealing in?uence on the basic properties of the as-deposited ITO nanorod ?lms was studied in the range of 100–500 °C for two hours in air. The crystallinity of the ITO nanorod ?lms was enhanced with the increasing annealing temperature, and the average transmission of the as-deposited ITO nanorod ?lms in the visible range was 90%. This value did not change signi?cantly after the annealing process. The optical bandgap of the as-deposited ITO nanorod ?lms was 3.94 eV and increased slightly after annealing. The sheet resistance of the as-deposited ITO nanorod ?lms was 12.9 Ω/□ and increased to 57.8 Ω/□ at an annealing temperature of 500 °C. The as-deposited ITO nanorod ?lms showed nanorod structures with average diameters of 79 nm, which changed slightly with the annealing temperature. The root mean square roughness of the as-deposited ITO nanorod ?lms was 7.9 nm and changed slightly with annealing. The as-deposited ITO nanorod ?lms had an average contact angle of 110.9°, which decreased to 64.2° at an annealing temperature of 500 °C. The experimental results showed that varying the annealing temperature in?uenced the structural, electrical and wettability properties of the ITO nanorod ?lms while the optical properties and surface morphology were almost unaffected.
关键词： Physical Properties,Annealing Temperature,Glancing-Angle Ion-Assisted Electron-Beam Evaporation,ITO Nanorod Films
更新于2025-09-09 09:28:46
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Electrophoretic Deposition Fabrication and Magnetic Manipulation of Magnetic Semiconductor Films
摘要： ZnO:Co semiconductor films were synthesized by a two-step electrophoretic deposition method. Various morphologies, including solid, crystal-grain or nanorod-array film, could be obtained by tuning the deposition conditions. Careful characterizations indicate the morphologies and structures have great effect on the magnetic and optical properties of the films. Significant difference of magnetism was investigated in the films prepared under different deposition potentials. The origination of the magnetism difference and the mechanism of the electrophoretic deposition were discussed.
关键词： Electrophoretic deposition,Magnetic semiconductor films,Nanorod arrays,Magnetism difference
更新于2025-09-09 09:28:46
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Redox-Mediated Shape-transformation of Fe3O4 Nanoflake to Chemically Stable Au-Fe2O3 Composite Nanorod for High-Performance Asymmetric Solid-State Supercapacitor Device
摘要： Development of a stable and highly active metal oxide based electrochemical supercapacitor is a major challenge. Herein, we report Au-Fe2O3 nanocomposite having tiny amount of gold (3 atomic % Au) by employing a simple redox-mediated synthetic methodology using modified hydrothermal system. Structural and morphological studies of the synthesized Au-Fe2O3 nanocomposite have been performed both experimentally (XRD, IR, Raman, XPS, TEM and FESEM analyses) and theoretically (WIEN2K). A probable dissolution-nucleation-recrystallization growth mechanism has been suggested to explain the morphological transformation from Fe3O4 nanoflake to Au-Fe2O3nanorod. We have observed the superior chemical stability of Au-Fe2O3 nanocomposite in acidic medium due to composite formation. The electrochemical measurement of the synthesized Au-Fe2O3 nanocomposite exhibits specific capacitance of ~570 F g-1 at the current density of 1 A g-1 in 0.5 M H2SO4 electrolyte. The result is superior compared to the mother component i.e., Fe2O3 (138 F g-1) under identical condition. It is credited to its higher specific surface area and composite effect. Theoretically, decrease in band gap associated with increase in conductivity support the superiority of Au-Fe2O3 nanocomposite compared to the mother compound i.e., Fe2O3. In addition, electrochemical kinetic analysis showed that the charge-storage mechanism is mostly from a dominant capacitive process (78 % at 1.5 mV s-1). Solid-state asymmetric supercapacitor device has been fabricated using synthesized Au-Fe2O3 composite nanorod as positive and activated carbon as negative electrodes. The asymmetric solid-state device exhibits maximum energy density of 34.2 Wh kg-1 and power density of 2.73 kW kg-1 at current densities 1 A g-1 and 10 A g-1, respectively. Thus, the synthesized nanocomposite shows excellent activity as a supercapacitor with long term durability (91% capacitance retention) up to 5000 cycles even in acidic medium.
关键词： Shape-transformation,Redox mediated synthesis,Chemical stability,High power density/energy density,Au-Fe2O3 composite nanorod,Asymmetric supercapacitor
更新于2025-09-09 09:28:46
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Investigation of gold/GaN nanorod arrays for hypersonic detection: The effect of periodicity
摘要： Gold nanodisk arrays on the upper surface of GaN nanorods were developed with the aim of achieving hypersonic imaging with a detection frequency above 10 GHz. In this paper, we report the interesting phenomenon that the hypersonic signal detected by a single gold nanodisk in this structure might be dependent on the array periodicity and rod length. When the array periodicity is of the same order of or longer than the surface hypersonic wavelength, the detected signal would be enhanced by the period-dependent resonance of the surface hypersonic waves scattered by the nanorod/substrate interface. When the array periodicity is smaller than the surface hypersonic wavelength, the coupling of extensional modes between neighboring nanorods, as the detection frequency approaches the coupled-extensional-mode frequency, would enhance the detected signals. Although these enhancements are beneficial to heat transport at nanorod/substrate interfaces, they will cause cross-talk between the neighboring detection rod unit and should be avoided by choosing the correct period for imaging array applications. Our result further indicates that the extensional mode coupling could be avoided by increasing the rod-length to shift the extensional mode frequency away from the detection frequency. This work not only investigates the transport behavior of hypersonic-frequency acoustic phonons at the interface between a bulk material and a nanostructure, but also suggests that the effects of the periodicity and nanorod length need to be taken into consideration for the design of future hypersonic imaging arrays.
关键词： acoustic phonons,periodicity,gold/GaN nanorod arrays,imaging arrays,hypersonic detection
更新于2025-09-09 09:28:46
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Solar-charged pseudocapacitors: Simultaneous conversion and storage of solar energy in ZnO@NiO nanorod arrays
摘要： In this paper, bias-free solar-driven pseudocapacitors based on ZnO@NiO nanorod arrays had been reported, which enable the synergistic coupling of light harvesting and electrochemical storage within one single electrode. When solar-charging, ZnO/NiO PN junction served as a driving force to separate the excitons and induce electron-injection through the interface to counter electrode forming charging bias. At this bias, the OH- trapped by photoexcited holes can make redox reaction with NiO and produce electrons. As expected, under a 1-sun illumination and no external electric bias, this ZnO/NiO composite exhibits a good specific capacitance of 44.5 F g?1 at current densities of 0.5 A g?1 as well as a good cycling performance (99% capacity retention after 50 cycles). Additionally, the capacitance equation was derived to account for the boosted capacitance as the increased solar-charging time. These findings here suggest the potential of further developing light-induced electrical energy storage and release on demand by a one-component light-charged capacitors.
关键词： solar energy conversion,ZnO@NiO nanorod arrays,photo-capacitor,pseudocapacitance
更新于2025-09-04 15:30:14