Liu X.Xue J.Li D.Cao L....
9页查看更多>>摘要：C-Doping TiO2 could significantly enhance the photocatalytic activity, as found in experiments, but the mechanism behind is elusive. We systematically investigated the configurations, electronic and photocatalytic properties of C-doped anatase TiO2 by first-principles calculation. The results show that the structures for the C-anion (Ca) and C-cation (Cc) doped TiO2 could exist in different form, and the Ca and substitutional Cc doping are favored under O-poor and O-poor conditions, respectively. The calculated electric and optical properties demonstrate that the substitutional Cc doping play the vital role in narrowing the bandgap, responsible for enhanced visible-light absorption of the TiO2. Finally, the calculated band edges using the hybrid functional of Heyd, Scuseria and Ernzerhof (HSE) suggested that substitutional Cc doped TiO2 could exhibit the small band gap and appropriate band edges for visible-light photocatalytic water splitting. The findings could not only give new insights into atomistic origin of visible-light response and photocatalysis of the C-doped TiO2.
原文链接:
NSTL
Elsevier
Liu J.Liu A.Chen Y.Tu X....
5页查看更多>>摘要：? 2021 Elsevier B.V.Praseodymium ion (0.5, 1 mol%) and magnesium ion (1, 5 and 7 mol%) co-doped LiNbO3 crystals have been grown by Bridgman method. The crystal was designed to absorb idler generated by the quasi parametric chirped pulse amplification (QPCPA) system near 1588 nm (the pump is 1064 nm and signal is 3200 nm). The contents of Praseodymium (Pr) and magnesium (Mg) ions in the crystals were measured, and the crystal structure and Raman vibration mode were characterized. The optical properties of the crystal were systematically investigated, the transmittance of the crystal at 3200 nm and 1064 nm was about 75%, and there is an obvious absorption band at 1588 nm. The thermal properties of the crystal were studied, and the results showed that the thermal properties of the crystal were improved by doping Mg2+. The laser damage threshold of Pr3+(0.5mol%)-Mg2+(7mol%) co-doped LiNbO3 crystal was as high as 109.73 × 107 W/cm2 (@1064 nm, 5 ns).
原文链接:- NSTL
- Elsevier
Pushpitha R.D.Thirumalai J.
5页查看更多>>摘要：? 2021 Elsevier B.V.Light Hole (LH) and Heavy Hole (HH) transmission, spin polarization and dwell time are theoretically studied in CdTe/CdMnTe heterostructures for different pressures. The transfer matrix method is used to find the transport properties taking Dresselhaus spin-orbit coupling into account. Sharp resonance peaks with high transmission probability are obtained for HH. A possibility to manipulate the spin-polarized dwell time of holes in this heterostructure using pressure is inferred from the results.
原文链接:- NSTL
- Elsevier
Sudha S.Cholan S.Sridhar S.
5页查看更多>>摘要：? 2021 Elsevier B.V.The research work demonstrates the facile fabrication of nickel molybdates (NiMoO4) nanocatalyst via greener approach using moringa oleifera extract as chelating agent. The phase and crystalline structure, functional groups, morphology were characterized using characterization tools. The XRD patterns confirms the monoclinic phase structure of α-NiMoO4 with the crystallite size of ~18 nm. The existence of Ni 2p, Mo 3d and O1s energy levels characteristics in the synthesized nanocatlayst was determined from the XPS analysis. Then the prepared nanocatalyst (α-NiMoO4) used as active material to degrade the methylene blue (effluent dye) under visible light and solar radiation. The photo-degradation efficiency of MB achieved to be 91% over the optimal nanocatalyst (NiMoO4) under solar radiation condition over 2 h and 81% for visible light under the same condition. Pseudo first order reaction rate constants of NiMoO4 for both visible light and solar light irradiation are determined to be 0.01387 min?1 and 0.01902 min?1, respectively.
原文链接:- NSTL
- Elsevier
Yassine R.Abdallah A.M.Awad R.Bitar Z....
5页查看更多>>摘要：? 2021 Elsevier B.V.Nanocomposite (x)NiO/(1-x)CdFe2O4 were synthesized using co-precipitation method with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1. The X-ray diffraction patterns reveal the presence of NiO and CdFe2O4 phases with no chemical reaction between both phases. The scanning electron microscope images show the agglomeration between the particles, revealing the magnetic interaction between NiO and CdFe2O4 nanoparticles. The band-gap energy Eg, measured from UV–vis spectra, decreases with the increase of the particle size measured from the transmission electron microscope. The obtained data from the vibrating sample magnetometer indicate that NiO and CdFe2O4 nanoparticles are interacting magneto-statically. The coercivity and the saturation magnetization values of the nanocomposites are found to be in the ranges 3.22–378.62 G and 0.27–2.34 emu/g respectively. Exchange couple interaction between NiO and CdFe2O4 is confirmed from the single peak observed in switching field distribution curves.
原文链接:- NSTL
- Elsevier
Villada J.A.Ramirez-Cardona M.Hernandez-Landaverde M.A.Jimenez-Sandoval S....
5页查看更多>>摘要：? 2021 Elsevier B.V.The effect of the substrate temperature (Ts) on the growth of Cu2-xTe films using the RF sputtering technique has been studied through a structural assessment of the different trigonal (space group P3m1) phases encountered in the range 100–350 °C. A new stoichiometric Cu7Te4 phase (δ′) with Z = 1 is proposed, and it is present in all the temperatures studied. Low-angle peaks (2θ < 20°) of Glancing Incidence X-ray Diffraction (GIXD) patterns are consistent with the formation of commensurate phases (forms α′) through variations in the c parameter whose value can be as large as 25.47 ?. The base modulation vector is the c parameter of the unit-cell of phase δ′ that, in this work, resulted in a value of 3.61 ?. The origin of the observed commensurate phases has been ascribed to an occupancy-wave modulation. Whereas at high temperatures (Ts > 250 °C), the major phase is δ' (Cu7Te4 or Cu2-xTe with x = 0.25), the predominant phase, for Ts < 250 °C, is the commensurate superstructure 7C with higher [Cu]/[Te] ratio (x < 0.25). The transition between these two thermal regimes is stated at a temperature of about 250 °C. Maintaining a constant global composition, the devaluation of [Cu] in films, with the temperature above the transition range, is explained in terms of diffusion of copper downward the film and towards its edges.
原文链接:- NSTL
- Elsevier
Kurochkin M.A.Lahderanta E.Afanaseva E.V.Kolesnikov E.Y....
5页查看更多>>摘要：? 2021 Elsevier B.V.Novel strategies to obtain remote temperature sensing with good spatial and thermal resolution are in high demand in various applications, where traditional thermometers are inappropriate. The majority of developed luminescence thermometers utilize thermally-coupled levels with their inherent limitation of thermal sensitivity and problems with signal discriminability. We report mixed-valent Eu2+/Eu3+-doped MgAl2O4 phosphor as a ratiometric thermal sensor, which is free of these drawbacks. Different temperature behavior of Eu2+ and Eu3+ emission bands provides luminescence thermometry within range of 298–523 K. High absolute and relative thermal sensitivities of 0.084 K-1 and 0.83% K?1, respectively, as well as sub-degree temperature resolution indicate that MgAl2O4:Eu2+/Eu3+ phosphor is a promising material for optical thermometry.
原文链接:- NSTL
- Elsevier
Radzi Z.I.Balakrishnan V.Rahim N.A.Raihan S.R.S....
5页查看更多>>摘要：? 2021 Elsevier B.V.Spinel LiNi0.5Mn1.5O4 (LNMO) cathode are effectively obtained by one-pot hydrothermal synthesis. Scanning electron microscopy (SEM) reveals the hybrid morphological of LNMO, featuring cotton-like structures (400–800 nm) and rod-like structures (90–150 nm). The equivalent circuit well describes the Nyquist plot to separate the grain and grain boundary effects. According to the Maxwell-Wagner model, the complex permittivity confirms non-homogenous layers' existence; highly conducting grains and poorly conducting grain boundaries. Non-overlapping polar tunneling (NSPT) and correlated barrier hopping (CBH) are two responsible models for the conduction mechanism at low and high temperatures. Further, identical activation energy values are observed for hopping frequency, and peak frequency from normalized parameters Z’’/Z’’ max and M’’/M’’ max, suggesting Li+ ions are the dominant charge carriers. The LNMO/Li cell delivers higher discharge capacity than commercial LNMO/Li cell from prior study, credits from the bridging features between rod-like and cotton-like particles.
原文链接:- NSTL
- Elsevier
