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Photocatalytic degradation of phenol by LaFeO3 nanocrystalline synthesized by gel combustion method via citric acid route
摘要： Focusing on the photocatalytic degradation of phenol under visible light, the synthesized lanthanum orthoferrites (LaFeO3) by gel combustion method using citric acid as sacrificial agent were investigated. With the highest reaction temperature of 200 °C, the physicochemical properties of synthesized samples were characterized by X-Ray diffraction (XRD) analysis, Brunauer–Emmet–Teller (BET), and Energy Dispersive X-Ray spectroscopy (EDS). On the other hand, UV–Vis spectroscopy analysis was carried out to determine the phenol photodegradation activities and mechanism. The results suggested the well-defined LaFeO3 nanocrystals with specific area of 28 m2 g?1 were successfully synthesized. Besides that, variations in operating parameters such as pH, catalyst dosage and initial concentration of phenol in synthetic wastewater were also examined. In conclusion, LaFeO3 nanocrystalline exhibited an exceptional photocatalytic activity for phenol degradation, thus providing a perfect alternative for pharmaceutical wastewater treatment.
关键词： Citric acid,Photocatalytic activity,Lanthanum orthoferrite,Phenol,Gel combustion
更新于2025-09-23 15:23:52
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Fraction of Rare-Earth (Sm/Nd)-Lanthanum Ferrite-Based Perovskite Ferroelectric and Magnetic Nanopowders
摘要： Multiferroic compound, especially LaFeO3-based perovskite nanopowders that exhibit robust simultaneous ferromagnetism and ferroelectricity, are widely investigated and applied in different applications. In this work, we report the synthesis and characterization pertaining to fraction of rare-earth (Sm/Nd)-substituted lanthanum ferrite based perovskite nanopowders via solid-state technique. The multiferroic phenomenon is the fundamental approach to combine both the ferromagnetic and ferroelectric properties in a single system. Reduction in crystallite size, as well as some lattice distortion effects, are included to show the possibilities of tuning the lattice structure, electrical, optical as well as the magnetic properties which are closely connected to the ferroelectric behavior and magnetism. At room temperature, the ferroelectric behavior of La0.9(Sm/Nd)0.1FeO3 exhibiting a P-E hysteresis loop became more and more pronounced, indicating the electrical leakage is greatly reduced. The canted antiferromagnetic hysteresis loop shows that the rare-earth (Sm/Nd) ion can significantly affect the magnetic parameters of the materials.
关键词： Lanthanum ferrite,x-ray diffraction,optical and magnetic properties,solid-state reaction,ferroelectric,UV–Vis spectroscopy
更新于2025-09-23 15:23:52
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Electrode Dependence of Local Electrical Properties of Chemical-Solution-Deposition-Derived BiFeO <sub/>3</sub> Thin Films
摘要： The nanoscale electrical properties of chemical solution deposition(CSD)-derived BiFeO3 grown on pulsed laser ablated La0.67Sr0.33MnO3//SrTiO3 (001) thin film heterostructures are investigated using a host of scanning probe microscopy techniques, including electrostatic force microscopy(EFM), scanning Kelvin probe microscopy(SKPM), piezoresponse force microscopy (PFM), and conductive AFM(CAFM). EFM and SKPM confirm the p-type nature of the CSD derived BFO thin films as well as charge accumulation at the film surface after electrical bias. For BiFeO3 films of a fixed thickness (~35 nm), the local current-voltage (I-V) behavior obtained by CAFM is strongly dependent on the La0.67Sr0.33MnO3 bottom electrode thickness. BiFeO3 films on a 20 nm thick La0.67Sr0.33MnO3 demonstrate the typical switchable diode behavior governed by polarization orientation. However, when the thickness of La0.67Sr0.33MnO3 is reduced to less than 5 nm, the BiFeO3 films show only forward diode behaviors regardless of polarization orientation, when the applied bias is up to ±4 V. Higher sweep bias (i.e. ±8V) breaks down the diode, following which the BiFeO3 film shows strong resistive switching. The interface band structure for the ultra-thin LSMO case, which is very sensitive to accumulation/depletion of carriers at the BFO-LSMO interface, is suggested as the trigger for this resistive switching.
关键词： chemical solution deposition,ferroelectric,electrical properties,ultrathin lanthanum strontium manganite,p-type bismuth ferrite thin films
更新于2025-09-23 15:23:52
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The effect of oxygen plasma treatment on the field emission properties of lanthanum hexaboride tip emitter
摘要： Polycrystal lanthanum hexaboride (LaB6) tip field emitter has been prepared using the electrochemical etching technique. The effects of oxygen plasma treatment on its morphology, structure and field emission properties are mainly discussed. The results reveal that the surface morphology of emitters did not change significantly after oxygen plasma treatment. The oxygen plasma treatment does not introduce any new phase into LaB6 emitter, but eliminates surface contaminants, which lead to lower work function. The cathode treated by 2 min shows the best emission performance during the field emission measurement. It obtains 8.2 μA at 2000 V, especially exhibiting strong ability of anti oxygen ion bombardment.
关键词： electrochemical etching,field emitter,lanthanum hexaboride
更新于2025-09-23 15:23:52
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Effect of High Temperature Forming Gas Annealing on Electrical Properties of 4H-SiC Lateral MOSFETs with Lanthanum Silicate and ALD SiO<sub>2</sub> Gate Dielectric
摘要： We investigated the impact of an initial lanthanum oxide (La2O3) thickness and forming gas annealing (FGA) conditions on the MOSFET performance. The FGA has been shown to dramatically improve the threshold voltage (VT) stability of 4H-SiC MOSFETs. The FGA process leads to improve VT instability and high field effect mobility due to reduction of the interface states density as well as traps by passivating the dangling bonds and active traps in the Lanthanum Silicate dielectrics. By optimizing the La2O3 interfacial layer thickness and FGA condition, SiC MOSFETs with high threshold voltage and high mobility while maintaining minimal VT shift are realized.
关键词： Silicon carbide,Lanthanum Silicate,Atomic layer deposition,Forming Gas Annealing
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Development of a Low-Work-Function Thermionic Cathode by Coating with LaB<inf>6</inf> and Carbide
摘要： A novel electron gun with lanthanum hexaboride (LaB6) thermionic cathodes with relatively low work functions is being developed by coating the metal surface with another material. When operated under thermionic emission mode, this tool provides both high brightness and high beam current simultaneously, has a long lifetime, and offers good stability during operation. Herein, we describe the basic design concept for a novel LaB6 cathode involving infiltration of a carbide solution. Moreover, we experimentally measured the thermionic-emission-mode work function of the rhenium surface modified with a LaB6 single-crystal powder and carbide solution.
关键词： work function,carbide solution,lanthanum hexaboride,thermionic emission
更新于2025-09-23 15:21:21
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Photocatalytic degradation of azophloxine on porous La2Ti2O7 prepared by sol-gel method
摘要： Cetyltrimethyl ammonium bromide (CTAB) was used in a sol-gel route to synthesize porous lanthanum titanate. The materials are composed of perovskite La2Ti2O7 in monoclinic system. The addition of CTAB does not cause phase transformation, but leads to a slight decreasing tendency of La2Ti2O7 crystallite size. Both the pore volume and pore size distribution range are enlarged after using CTAB. The sample obtained with 4 g CTAB has the maximum BET specific surface area of 42.4 m2/g. When the amount of CTAB is less than 4 g, the increase in photocatalytic degradation efficiency is almost in linear relationship to the amount of CTAB. The reaction rate constants are 0.0032, 0.0116 and 0.0237 min-1 on the La2Ti2O7 samples obtained using 0, 2 and 4 g CTAB. The functional groups in azophloxine molecule are decomposed during photocatalytic oxidation with extending irradiation time.
关键词： cetyltrimethyl ammonium bromide,azophloxine,degradation,photocatalysis,lanthanum titanate
更新于2025-09-23 15:21:21
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Oxygen pumping based on <i>c</i>-axis-oriented lanthanum silicate ceramics: challenge toward low operating temperature
摘要： A new electrochemical oxygen separation pump was developed by using c-axis-oriented La9.66Si5.3B0.7O26.14 (c-LSBO), which has high oxide-ionic conductivity (>1013 S cm11) up to 300°C. Interfacial resistance between the electrode and c-LSBO was investigated to realize the full potential of LSBO as an oxygen separation material. The formation of a Sm-doped CeO2 (SDC) thin ?lm (thickness: 300 nm) between the electrode and c-LSBO was effective for suppressing the interfacial resistance. Furthermore, a mixed conductive La0.6Sr0.4Co0.78Ni0.02Fe0.2O31¤ (LSCFN) was applied to the electrode for enhancing the oxygen reduction/evolution activity on the electrode. The LSCFN/SDC/c-LSBO symmetric cell showed an oxygen permeation ?ux of 3.5 mL cm12 min11 (1.0 A cm12) at 600°C under an applied DC voltage of 1.5 V; this value was 67 times that of Pt/c-LSBO. This oxygen pump based on the LSCFN/SDC/c-LSBO symmetric cell would ?nd promising application in oxygen separation at intermediate temperatures. Further reduction of the interfacial resistance and polarization resistance of the electrode may decrease the operating temperatures to below 400°C.
关键词： Mixed conductor,Oxygen separation,Oxide-ionic conductor,C-axis-oriented lanthanum silicate
更新于2025-09-23 15:21:21
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[IEEE 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Agadir, Morocco (2019.11.27-2019.11.30)] 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Elaboration and Characterization of (Ce,Sm) Doped Lanthanum Oxychloride for Photovoltaic Solar Cell
摘要： The spectral incoherence due to the emission of sunlight and the absorption of silicon solar cells cause large solar energy losses, leading to a low photovoltaic efficiency. So that low energy photons cannot be used efficiently, while the majority of high energy photons are dissipate. Doped rare earth ions (RE) are expected to solve this problem, thanks to their spectral modification characteristics and luminescence properties. In this work we present the synthesis of LaOCl co-doped by trivalent rare earth with the couple of Ce3+/Sm3+ employed in photovoltaic cell down conversion. LaOCl: Ce3+/Sm3+ phosphors were prepared by the solid-state method, and their structures properties were investigated by using X-ray diffraction, Infrared Spectroscopy and MEB analysis. The study shows that tetragonal LaOCl: Ce3+/Sm3+ can be synthesized by the solid-state reaction at 700 °C for 4 h.
关键词： Down conversion,Lanthanum oxychloride,Solid-state,Photovoltaic,Rare Earth
更新于2025-09-23 15:21:01
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Decoupling mesoscale functional response in PLZT across the ferroelectric – relaxor phase transition with contact Kelvin probe force microscopy and machine learning
摘要： Relaxor ferroelectrics exhibit a range of interesting material behavior including high electromechanical response, polarization rotations as well as temperature and electric field-driven phase transitions. The origin of this unusual functional behavior remains elusive due to limited knowledge on polarization dynamics at the nanoscale. Piezoresponse force microscopy and associated switching spectroscopy provide access to local electromechanical properties on the micro- and nanoscale, which can help to address some of these gaps in our knowledge. However, these techniques are inherently prone to artefacts caused by signal contributions emanating from electrostatic interactions between tip and sample. Understanding functional behavior of complex, disordered systems like relaxor materials with unknown electromechanical properties therefore requires a technique that allows to distinguish between electromechanical and electrostatic response. Here, contact Kelvin probe force microscopy (cKPFM) is used to gain insight into the evolution of local electromechanical and capacitive properties of a representative relaxor material lead lanthanum zirconate across the phase transition from a ferroelectric to relaxor state. The obtained multidimensional data set was processed using an unsupervised machine learning algorithm to detect variations in functional response across the probed area and temperature range. Further analysis showed formation of two separate cKPFM response bands below 50°C, providing evidence for polarization switching. At higher temperatures only one band is observed, indicating an electrostatic origin of the measured response. In addition, from the cKPFM data qualitatively extracted junction potential difference, becomes independent of the temperature in the relaxor state. The combination of this multidimensional voltage spectroscopy technique and machine learning allows to identify the origin of the measured functional response and to decouple ferroelectric from electrostatic phenomena necessary to understand the functional behavior of complex, disordered systems like relaxor materials.
关键词： phase transition,machine learning,Relaxor ferroelectric,lead lanthanum zirconium titanate,piezoresponse force microscopy,k-means clustering,contact Kelvin probe force microscopy
更新于2025-09-23 15:21:01