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Lithium-ion capacitors (LICs) have emerged as attractive energy storage devices to bridge the gap between lithium-ion batteries and supercapacitors. While the distinct charge storage kinetics between the anode and the cathode is s...
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Lithium-ion capacitors (LICs) have emerged as attractive energy storage devices to bridge the gap between lithium-ion batteries and supercapacitors. While the distinct charge storage kinetics between the anode and the cathode is still a challenge to the widespread application of LICs, the key to improving the energy density of these devices is to widen the operating voltage window and balance the mismatch of the electrode kinetics. To this end, we propose a strategy based on electrostatic attraction by adjusting the B and N atom contents of boron carbonitride (BCN) electrode materials to alter their electronegativities and successfully prepared B-rich and N-rich BCN nanotubes (BCNNTs) via a facile solid-phase synthesis approach. The B-rich BCN (B-BCN) cathode and N-rich BCN (N-BCN) anode noticeably enhance the adsorption of anions and cations, promoting a matching degree between the anode and cathode. In particular, the rationally designed B-BCN//N-BCN LIC achieves a maximum voltage range of 4.8 V, setting a new record for LICs. Furthermore, the energy density reaches up to 200 Wh kg(-1) (based on the total mass of cathodic and anodic active materials). Density functional theory calculations provided insight into the mechanism underlying our strategy of widening the voltage range. Our philosophy provides new design guidelines and alternatives for identifying and optimizing high-performance electrodes for energy storage devices.
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The anisotropic properties of a nonlinear optical (NLO) material are of critical importance for comprehending the intrinsic characteristics and evaluating the further applications. However, due to the severe layered growth habits,...
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The anisotropic properties of a nonlinear optical (NLO) material are of critical importance for comprehending the intrinsic characteristics and evaluating the further applications. However, due to the severe layered growth habits, the anisotropic investigations of the NLO crystal CdTeMoO6 with a quasi-two dimensional structure have been severely hindered. Here, a detailed study of the bulk growth, exhaustive thermal properties and polarized Raman spectra for CdTeMoO6 single crystal are provided and all of them exhibit obvious anisotropic characteristics. Based on high quality crystal CdTeMoO6, the spontaneous Raman spectra along X and Z-axis with different configurations show the strongest Raman shifts at 921.6 and 944.1 cm(-1). More importantly, the relationship between structure and the anisotropic physical properties, including thermal expansion, specific heat, thermal diffusion, thermal conductivity and hardness of the CdTeMoO6 crystal have also been systemically discussed, which provide a guidance for the further application of CdTeMoO6. (C) 2018 Published by Elsevier B.V.
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Single crystals of Bi2Mo2.66W0.34O12 with dimensions up to 70 mm x 55 mm x 45 mm were successfully grown using a top-seeded solution growth (TSSG) method with a MoO3-WO3 mixture as a flux. The material crystallizes in centrosymmet...
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Single crystals of Bi2Mo2.66W0.34O12 with dimensions up to 70 mm x 55 mm x 45 mm were successfully grown using a top-seeded solution growth (TSSG) method with a MoO3-WO3 mixture as a flux. The material crystallizes in centrosymmetric space group P2(1)/c (no. 14), with unit cell parameters of a = 7.7212(8)angstrom, b = 11.4938(12)angstrom, c = 11.9970(12) angstrom, and beta = 115.5070(10)degrees. The as-grown crystals exhibit {100}, {010}, {011}, {110}, {021}, {012}, {120}, {-111}, {-102}, and {1-1-2} facets, which are in good agreement with the predicted growth morphology based on the Bravais-Friedel and Donnay-Harker (BFDH) method. Highresolution X-ray diffraction (HRXRD) measurement on the (040)-faced plate shows that the full-width at half-maximum (FWHM) of the rocking curve is 54 '', which indicates high crystal quality. Our measurements show that it melts congruently and exhibits a wide transmission range from 475 nm to 5200 nm. It is worth noting that Bi2Mo2.66W0.34O12 has a large birefringence (Delta n = 0.24 at 480 nm), indicating that the crystal can be a promising polarizing optical material.
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High quality Er,Yb:CaGdAlO4 (Er,Yb:CALGO) single crystals with a diameter around 1 mm were successfully grown and investigated for the first time by the laser heated pedestal growth (LHPG) method. The cracking mechanism of (001) p...
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High quality Er,Yb:CaGdAlO4 (Er,Yb:CALGO) single crystals with a diameter around 1 mm were successfully grown and investigated for the first time by the laser heated pedestal growth (LHPG) method. The cracking mechanism of (001) planes was studied via density functional theory (DFT). The doping concentration of Er3+ and Yb3+ was calculated by X-ray fluorescence analysis (XRF). The XRD pattern confirms that the phase of Er,Yb:CALGO is consistent with pure CALGO and the crystal quality was measured through Laue back-reflection measurements. The optical properties including absorption spectra, mid-infrared fluorescence spectra and fluorescence lifetime of the Er3+, Yb3+ co-doped CALGO crystal were measured at room temperature to assess its potential for improving absorption efficiency. Further research found that the disordered structure of the CALGO crystal could achieve wider absorption and emission bands accompanied with efficient energy transfer from the excited Yb3+ to Er3+. Our results indicated that the Er,Yb:CALGO crystal is a promising material for achieving tunable mid-infrared lasers.
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A new generation of orthogonally polarized dual-wavelength lasers was demonstrated using a dye mode-locked neodymium-doped yttrium aluminum garnet laser for the first time. With a hexagonal Cs2TeMo3O12 as the Raman medium, efficie...
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A new generation of orthogonally polarized dual-wavelength lasers was demonstrated using a dye mode-locked neodymium-doped yttrium aluminum garnet laser for the first time. With a hexagonal Cs2TeMo3O12 as the Raman medium, efficient dual-wavelength stimulated Raman scattering was obtained at 1175 and 1154 nm with similar output power, corresponding to the stretching vibration of Mo-O and the asymmetric stretching vibrations of Mo-O and Te-O groups, respectively. The power ratio of two Raman components can be flexibly adjusted by tuning the polarization of the incident laser, which can be tuned from 0% to 100%. Laser sources with such a small wavelength separation could prove interesting for the difference-frequency generation of terahertz waves in the 4.6 THz range. Our study provides a simple and flexible method to achieve a promising dual-wavelength laser source in orthogonal polarization by Raman-based nonlinear frequency conversions. (C) 2020 Optical Society of America
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The self-frequency-doubling (SFD) lasers in visible region are of importance for optical applications. In this work, SFD green laser was realized on newly designed nonlinear optical crystal Nd doped Ca3Ta-Ga3Si2O14 (Nd:CTGS). By o...
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The self-frequency-doubling (SFD) lasers in visible region are of importance for optical applications. In this work, SFD green laser was realized on newly designed nonlinear optical crystal Nd doped Ca3Ta-Ga3Si2O14 (Nd:CTGS). By optimizing the configurations, measuring the refractive indexes and coating the surfaces of Nd: CTGS crystal samples, the SFD green laser output at 533 nm was observed, and the maximum output power for type I (38.7 degrees, 30.0 degrees) crystal cut was obtained and found to be on the order of 71.58 mW. Meanwhile, the Nd: CTGS type I (38.7 degrees, 30.0 degrees) crystal cut was found to show low output threshold, being on the order of 0.52 W. The output power stability within 30 mins was observed to be better than 1%. (C) 2015 Elsevier B.V. All rights reserved.
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In this paper, porous microsphere M-ZnO/CeO2 (M = Ag, Au) plasmonic photocatalyst was prepared through a simple hydrothermal method and in situ photo-deposition. This photocatalyst shows excellent stability and high efficiency in ...
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In this paper, porous microsphere M-ZnO/CeO2 (M = Ag, Au) plasmonic photocatalyst was prepared through a simple hydrothermal method and in situ photo-deposition. This photocatalyst shows excellent stability and high efficiency in the complete mineralization of nonpolar gaseous molecules (CH4 and C2H4) under the simulated sunlight. The appreciable performance improvements are caused by the formation of heterojunctions and oxygen vacancy defects, the surface plasmon resonance (SPR) of noble metal nanoparticles as well as the 3D porous microsphere structures. Especially in this work, we systematically studied the effect of concentration changes of oxygen vacancy defects on photocatalytic performance by XPS, EPR and Raman characterization. Furthermore, a possible mechanism of photo-oxidation reaction in plasmonic photocatalyst system is discussed below. This study provides new inspiration for designing other plasmonic photocatalysts to remove nonpolar gaseous molecules.
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Photocatalytic overall water splitting is a promising environmental friendly technique to convert solar energy into hydrogen (H-2) and oxygen (O-2). Here, BiVO4 ultrathin nanosheets is found to disintegrate pure water into H-2 and...
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Photocatalytic overall water splitting is a promising environmental friendly technique to convert solar energy into hydrogen (H-2) and oxygen (O-2). Here, BiVO4 ultrathin nanosheets is found to disintegrate pure water into H-2 and O-2 simultaneously under simulated solar light irradiation without sacrificial reagents. And a novel 2D/2D BiVO4/Ti3C2 composites is successfully synthesized through electrostatic interaction between BiVO4 and Ti3C2 nanosheets. Because the unique 2D/2D heterojunction possesses large interface contact area and quite short charge transport distance, BiVO4/Ti3C2 displays much higher photoexcited carrier transfer and separation efficiency and ultimately exhibits remarkable photocatalytic overall water splitting activity. This work may provide the first experimental confirmation of ultrathin BiVO4 nanosheets with an ability of photocatalytic overall water splitting, and the 2D/2D combination between BiVO4 and Ti3C2 is an effective way for further improving the activity, which may provide guidance for designing efficient water splitting photocatalysts in the future.
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The rational design and fabrication of stable and efficient heterogeneous Fenton-like catalyst is of great significance for wastewater treatment, but is also fraught with obstacles. In this paper, we synthesized BiVO4@CuOx composi...
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The rational design and fabrication of stable and efficient heterogeneous Fenton-like catalyst is of great significance for wastewater treatment, but is also fraught with obstacles. In this paper, we synthesized BiVO4@CuOx composite catalyst through a simple hydrothermal method and in situ chemical deposition. The degradation of tetracycline (TC) is carried out as a main model pollutant through Fenton reaction assisted by light irradiation. The prepared catalyst exhibits superb efficiency and satisfactory stability for the degradation of TC owing to the synergistic effect of light irradiation and decomposition of H2O2. The factors influencing the degradation such as catalyst dosage, H2O2 concentration and initial pH value are also investigated. Moreover, a possible mechanism of degradation of TC in BiVO4@CuOx/H2O2 system is discussed based on the premise that center dot OH, center dot O-2(-) and h(+) are demonstrated to be the main active species via in-situ ESR measurements. This work puts forward a new suggestion for designing and synthesizing photo assisted Fenton-like catalyst to remove organic contaminants in sewage.
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