Mardaneh, Mohamad RezaKashi, Mohammad AlmasiGhaffari, Maryam
11页
查看更多>>摘要：Current-flow perpendicular to the layer planes giant magnetoresistance (CPP-GMR) of Ni/Cu multilayered nanowires (NWs) grown by an alternating current (AC) pulsed electrodeposition technique into anodic aluminum oxide (AAO) template with a pore diameter of 50 +/- 5 nm is studied at room temperature. The method used for obtaining GMR percentage is the 2-probe resistance measurement of the contact of released and aligned NWs on a glass substrate in the presence of a magnetic field. The structure and thickness of layers are investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), indicating the formation of well-ordered multilayers. The magnetic properties are studied by a vibrating sample magnetometer (VSM) and the first-order reversal curve (FORC) analysis. The maximum CPP-GMR of Ni/Cu multilayered NWs is obtained to be 2.6% for 17 and 2.7 nm thick Ni and Cu layers, respectively. The results show that Ruderman-Kittel-Kasuya-Yosida (RKKY) variation behavior of GMR values as a function of Cu spacer thickness is in accordance with theoretical models. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Chloromenite, Cu9O2(SeO3)(4)Cl-6, is the product of volcanic activity. To conduct various physical studies both natural and synthetic samples of chloromenite were used which resulted in a long-standing controversy regarding its crystal structure. We carried out the temperature dependent single crystal X-ray diffraction study in the range 100 - 370 K and established that the reflection conditions are consistent with a primitive monoclinic cell with the only possible P2(1)/n space group. Raman scattering evidences a complex interplay of crystal lattice and spin degrees of freedom. The observation of a sequence of short range fluctuation effects points to the existence of competing interactions or nearly degenerate energy scales. To gain microscopic understanding of the magnetic properties of Cu9O2(SeO3)(4)Cl-6 the first principles density functional theory calculations have been performed. Basing on the new data on magnetization and the hierarchy of exchange interaction parameters a model of Cu9O2(SeO3)(4)Cl-6 magnetic structure is suggested. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：The composite of biocompatible carbon dots (CDs) and lanthanide-based luminescent materials have high research value as a promising multifunctional material, which are ideally suited to information encryption and white LED. However, the aggregation-induced quenching of CDs in the solid state still troubles the synthesis of CDs with other solid luminescent materials. Herein, a facile strategy to fabricate polychromatic nanoplatform KLa(MoO4)(2): Eu3+@CDs by encapsulating CDs on the surface of KLM: Eu3+ with silicon shell is reported, in which the aggregation-induced quenching of CDs is avoided. Due to the overlapping of Eu-O charge transfer band with CDs excitation band, the red luminescence of Eu3+ ions and the blue fluorescence of can be emitted simultaneously under 395 nm excitation. By changing the proportion of KLa(MoO4)(2): Eu3+ in KLa(MoO4)(2): Eu3+@CDs, the mixture can emit "warm", "neutral", and "cold" white light, which can realize people's demand for indoor lighting requirements. Furthermore, a multi-mode information encryption by selectively triggering the luminescence of CDs or Eu3+ ions is also designed. All the results suggest that KLa (MoO4)(2): Eu3+@CDs have excellent luminescence properties that can be further investigated and applied in the field of white LEDs and information encryption. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：CeO2-ZrO2 based nanomaterials (CZ), as an oxygen buffer and noble metal support, have been widely used in three-way catalysts of exhaust gas purification due to unique oxygen storage/release c apacity. Surfactants are often utilized to modify the properties of CZ during the preparation. In this paper, four kinds of CeO2-ZrO2-Y2O3-La2O3 solid solutions were prepared by co-precipitation, and the effects of adding surfactant lauric acid at different stages of grain growth on the properties of the materials were analyzed by correlation characterization. The results show that the addition of lauric acid at the end of grain growth had no effect on the grain growth, but only modified the grain stacking mode, thus enhancing the thermal stability of CZ. However, the lauric acid added at the nucleation and growth stage of grain growth tends to selectively adsorb on the unstable (200) and (220) planes, forming an adsorption layer that inhibits the growth of the planes, which results in anisotropic growth of the (111) plane. Thus, more (200) and (220) planes are exposed, which contributes well to the formation of oxygen vacancies to the largest extent, especially in the nucleation stage. Consequently, the reduction temperature of the fresh sample was decreased by about 160 degrees C and 140 degrees C compared with no lauric acid and the addition of lauric acid at the end of grain growth, respectively, which exhibits excellent Pd-only three-way catalytic activity. (C) 2021 Elsevier B.V. All rights reserved.
Flemban, Tahani H.Amin, Mohammed A.Zelai, TaharhMahmood, Q....
8页
查看更多>>摘要：The charge and spin degrees of freedom of electrons employed together introduce a new field of electronics, known as spintronics, which has multifunctional applications in data storage, control, and transfer in supercomputing. In this perspective, we have comprehensively investigated cubic double perovskites Rb(2)Z(Cl/Br)(6) (Z = Ta, W, Re). More precisely, we explored their structural, electronic, magnetic, and thermal transports. The structural stability is addressed by a tolerance factor, enthalpy of formation, and Curie temperature calculations. Half metallic ferromagnetism (HMF), quantum exchange process, spin polarization, and exchange energies are explained in terms of hybridization and double exchange mechanism. Furthermore, spin-polarized thermal transports are revealed by investigating thermal conductivity, Seebeck coefficient, and power factor. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Exploring sustainable noble-metal-free photocatalyst still remains a huge challenge for highly efficient and durable photocatalytic H-2 production. In this work, Cu3P nanosheets were successfully synthesized by a simple hydrothermal method without using any organic solvents, and red phosphorus was used as the phosphorus source. A Z-scheme Cu3P/TiO2 photocatalyst without a noble metal was rationally fabricated to achieve UV-vis harvesting. Compared to TiO2, the optimized Cu3P/TiO2 photocatalyst displays much more excellent activity with the hydrogen evolution rate of 607.5 mu mol h(-1) g(-1), which is 30.4 folds higher than that of bare TiO2 photocatalyst under solar light irradiation. The enhancement of charge carriers separation efficiency in Cu3P/TiO2 is demonstrated by the photoluminescence (PL) spectra, transient photocurrent response and electrochemical impedance spectroscopy (EIS). Moreover, The photo-induced charge-transfer route of Cu3P/TiO2 is a Z-scheme transfer mode confirmed by selective deposition of Pt nanoparticles, the photocatalytic decomposition of Rhodamine B (RhB). In the Z-scheme system, the holes are left on the TiO2, and photo-exited electron will be enriched on Cu3P nanosheets for hydrogen evolution. This work will provide more insight into fabricating eco-friendly phosphide-based catalyst with efficient photocatalytic hydrogen property and sufficient durability for solar-to-chemical conversion and utilization. (C) 2021 Published by Elsevier B.V.
查看更多>>摘要：BaSnO3 (BSO) is one of the promising perovskite materials for high temperature thermoelectric applications. The pure BSO, Sr and Sb co-doped BSO materials were prepared by the polymerization complex method and annealed at 1473 K. The X-ray diffraction patterns confirmed the cubic structure of pure BSO and Sr-Sb co-doped BSO. The addition of Sr and Sb changed the morphology of BSO from microstructures to the layered and polygonal shaped nanostructure. The valence states of each elements of the samples were confirmed by the X-ray photoelectron spectroscopy. The addition of Sb5+ atom in Sn4+ site modified the electronic band structure thereby enhanced electrical conductivity. The highest power factor of 25.3 mu W/(m K-2) was achieved for the SrSb5(Sr: 5 mM and Sb: 5 mM in the polymerization complex method) at 578 K. The reduced thermal conductivity and increased power factor in SrSb5 resulted in the higher figure of merit of 2.1 x 10(-3) at 578 K. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Inhibiting the recombination of photogenerated charge carriers is of great significance to improve the photocatalytic performance. For hybrid heterostructure photocatalysts, the noble metal is often used to modulate the interfacial charge behavior, which is closed related to metal states. Herein, we construct graphite-like C3N4 and TiO2 (g-C3N4/TiO2) heterostructure with Au nanoparticles tailored on g-C3N4 to form multiple charge separation for high-efficiency charge separation. Due to the enhanced charge separation, Au/g-C3N4/TiO2 heterostructures exhibits excellent photocatalytic activity for pollutant removal and water splitting. The apparent rate constant of Rh6G photodegradation achieves 2 times higher increased compared with different g-C3N4/TiO2 heterostructures with Au modulation. Active species trapping experiments indicate that superoxide radicals (center dot O-2(-)) play a most important role in catalytic process. This work provides insights into the distinct roles of Au in heterostructure for significantly enhanced charge separation and paves the way forward in designing high-efficiency heterostructure photocatalysts with noble metal decorated. (C) 2021 Elsevier B.V. All rights reserved.
Abhijith, T.Ragavendran, V.Sasirekha, V.Reddy, V. S....
15页
查看更多>>摘要：Dye sensitized solar cells (DSSCs) have numerous advantages, but in order to use widespread industrial deployment we need to boost the power conversion efficiency. One promising approach to improve DSSC performance is to improve the spectral response of sensitizers with metal nanoparticle-based surface plasmon resonance. Even single shaped nanoparticles (NPs), however, have physical limitations. Thus, in this study a simple synthesis route is used to fabricate multishaped silver (Ag) NPs to create a coupled plasmonic effect in DSSC to cover more of the solar spectrum. The impact of multishaped AgNPs combinations are studied to determine which aspects improve the power conversion efficiency of DSSC. A detailed investigation was made of both the TiO2 (XRD) and AgNPs (UV-Vis spectrometry) to couple the impacts on the DSSC (I-V) with the combination of the morphologies (TEM and FESEM) of AgNPs. Synthesized AgNPs with distinct extinction cross section covers the visible and IR regime from 300 nm to 1100 nm by tuning its plasmonics band. It is inferred that multi-shaped AgNPs predominately enhance the light harvesting, charge separation and carrier transportation. The results show that the increment in short circuit current and open circuit voltage resulted in an increase of 45% overall power conversion efficiency in the standard DSSC device is attributed to the usage of multi-shaped AgNPs. Finally, a mechanism is proposed to support the outcome of the experiment by demonstrating the extinction cross section and the local field of the various shaped AgNPs using Finite-difference time-domain (FDTD) simulation. (C) 2021 Elsevier B.V. All rights reserved.
dos Santos, Caroline Santanada Silva, Stephany PiresLima, Alexandre de FariaScarminio, Jair...
10页
查看更多>>摘要：A low-cost and straightforward resynthesis process based on the complete thermal decomposition of the cathode material extracted from a batch of discarded LiCoO2 (LCO) batteries is described. After leaching the thermally decomposed products, the residue and the filtered solution were employed as feedstock for the resyntheses. The Co3O4 powder residue, filtered from the leached solution, and commercial Li2CO3 were employed to resynthesize the LiCoO2 compound by solid-state reaction. The filtered leached solution containing Li+ and Co2+ ions was used to resynthesize the LiCoO2 and LiNi1/3Co1/3Mn1/3O2 compounds by the sol-gel technique. In these resyntheses, commercial Li, Ni, and Mn acetates were used for compositional adjustments. The charge capacity of electrodes manufactured with the resynthesized compounds was measured by charge and discharge curves in a Li-metal oxide/LiClO4-EC:DMC/Li degrees electrochemical cell. (c) 2021 Elsevier B.V. All rights reserved.
NSTL
Elsevier