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Physica
North-Holland
Physica

North-Holland

0921-4526

Physica/Journal Physica
正式出版
收录年代

    Tuning the activation of O2 on Pt single-atom catalyst using external-electric field: A first-principles study

    Lu, ZhanshengMeng, SongjiePang, YudongXu, Guoliang...
    5页
    查看更多>>摘要：O2 activation has attracted cumulative interest in various applications. We used a first-principles calculation to investigate the effect of the external-electric field (EEF) on the activation of O2 on graphene supporting Pt singleatom (Pt/Graphene). Our result indicates that increasing the EEF enhance the initiation of O2 on Pt/Graphene. Charge-transfer from the surface to the adsorbed O2 play a significant role in the activation of O2 on Pt/Graphene, resulting in the formation of peroxide-anion (O22- ). Our in-depth and systematic electronic structure analysis reveals the internal physical mechanism of the activation of O2 tuned by EEF in the atomic and electronic level. This work provides fundamental understanding to the surface chemistry of Pt/Graphene and designing new graphene-based single-atom catalyst (SAC).
      原文链接:
    • NSTL
    • Elsevier

    Structural and radiation shielding features for BaSn1-xZnxO3 perovskite

    Hamad, R. M.Hamad, M. KhMhareb, M. H. A.Sayyed, M. I....
    9页
    查看更多>>摘要：In the present work, we investigate the structural, electronic and shielding properties of a series of BaSn1-xZnxO3 (x = 0.05, 0.10, 0.15, and 0.20) ceramic samples prepared using the conventional solid-state reaction. We use the Fourier transform infrared and X-ray diffraction (XRD) to delineate the structure, while the diffuse reflectance (R) spectra were used to determine the bandgap. The Rietveld refinement of the XRD patterns showed the emergence of a majority of cubic structures with the Pm-3m space group. The FTIR spectra for all-ceramic samples display three bonds around 613, 1066, and 1425 cm(-1) that corresponded with the stretching vibration of Sn-O, delta(SnOH) vibration, and the existence of C-O vibration, respectively. The bandgap enhanced gradually from 3.14 to 3.18 eV with increasing ZnO. The radiation shielding properties of the prepared samples have been investigated experimentally then we benchmarked the results with the theoretical values, and the maximum relative difference (RD) is 6.290. Consequently, we theoretically explored the rest of the radiation shielding parameters, including linear attenuation coefficient, equivalent atomic number, mean free path, transmission factor, electron density, electron conductivity, and neutron removal cross-section. All the radiation-shielding properties showed a gradual reduction with the addition of ZnO to the ceramic system, while the neutron removal cross-section showed a gradual enhancement. Accordingly, it is deduced that the present samples can be used in the radiation-shielding field.
      原文链接:
    • NSTL
    • Elsevier

    A study of Jiles-Atherton and the modified arctangent models for the description of dynamic hysteresis curves

    Hamel, MezianeOuslimane, Ahmed NaitHocini, Farid
    7页
    查看更多>>摘要：This paper considers the identification of hysteresis parameters for two different hysteresis models, operated in quasi-static and dynamic behaviors. The extended Jiles-Atherton model via the Bertotti approach and the improved arctangent model are tested and compared. The hysteresis measurement was performed via standard Epstein frame on automotive parts for different magnetization levels and frequencies. The robustness of the Levenberg-Marquardt algorithm is assessed via a comparison of measured, modeled hysteresis loops, and relative permeability profiles, at various frequencies.
      原文链接:
    • NSTL
    • Elsevier

    Strain-induced tunability of the optoelectronic properties of inorganic lead iodide perovskites APbI3 (A= Rb and Cs)

    Wang, ZhijieLiu, KongIslam, Md. RasidulIslam, A. S. M. Jannatul...
    10页
    查看更多>>摘要：Herein we investigate the influence of biaxial strain ranges from -2% to +2% on the optoelectronic properties of APbI3 (A = Rb and Cs) perovskites through first-principles density functional theory calculations. It has been explored that the biaxial strain in APbI3 (A = Rb and Cs) can significantly increase their absorbance, both in the visible and ultraviolet light energy range. The electronic band structure shows that the RbPbI3 and CsPbI3 compounds are all semiconductors with a direct bandgap of 1.05 eV and 1.28 eV, respectively, at the R-point. However, the bandgap of APbI3 (A = Rb and Cs) reveals a decreasing trend and has a tendency towards the metallic condition when the compressive strain is applied. Besides, due to the increase of tensile strain, the bandgap of APbI3 exhibits an increasing trend. Therefore, this study would provide a systematic way to satisfy the requirements of different optoelectronic device applications through biaxial strain.
      原文链接:
    • NSTL
    • Elsevier

    Optimization studies for nickel oxide/tin oxide (NiO/Xg SnO2, X: 0.5, 1) based heterostructured composites to design high-performance supercapacitor electrode

    Rafiq, SabeeraAlanazi, Abdullah K.Bashir, SherazElnaggar, Ashraf Y....
    8页
    查看更多>>摘要：This work describes component optimization studies for transition metal oxide composites (NiO/0.5 g SnO2 and NiO/1 g SnO2) synthesized using a simple co-precipitation process, as electrode materials for supercapacitor applications. XRD studies revealed the presence of cubic and tetragonal phases of crystals for NiO and SnO2, respectively. Crystallite sizes of NiO/0.5 g SnO2 and NiO/1 g SnO2 were determined from XRD data analysis, that were in range of ~10-11 nm. Morphological analysis revealed the formation of in homogenuous particles of NiO/0.5 g SnO2 and NiO/1 g SnO2 with great degree of aggregation. As synthesized NiO/1 g SnO2 and NiO/0.5 g SnO2 showed the specific capacitance of 1035.71 Fg(-1 )and 980.76 Fg(-1), respectively. Moreover, NiO/1 g SnO2 showed 64% capacitance retention at 5 mVs(-1) after 2000 consecutive CV cycles. In contrast, pure SnO2 exhibited specific capacitance of 648 Fg(-1) at scan rate of 5 mVs(-1), with 36% retention in capacitance. Results showed that 1 g SnO2 was the optimum concentration for NiO/SnO2 composite to get maximum electrochemical activity. High electrical conductivity and larger surface area arising from synergistic effects between NiO and SnO2 resulted in a great electrochemical response of NiO/1 g SnO2 nanocomposites. The inclusion of the SnO2 improved the electrical impedance spectroscopy results by facilitating the charge transfer.
      原文链接:
    • NSTL
    • Elsevier

    Structural correlation of phonon dynamics in Bismuth and Tellurium for the formation of Bismuth Telluride, using ultrafast transient absorption spectroscopy

    Saini, Saurabh K.Sharma, PrinceVashistha, NikitaTyagi, Lavi...
    7页
    查看更多>>摘要：The charge carrier and phonon dynamics are highly reliant on the material structural features, and understanding their dynamics help in interpreting the underlying phenomenological qualities of any material system. The phonon and carrier dynamics of Bi, Te, and BiTe3 thin films formed on a Si (100) wafer through thermal evaporation are discussed in this article. The Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis are used to characterize the structural features of these films. The dynamics of charge carriers and phonons are further determined using femtosecond ultrafast transient absorption spectroscopy (UFTS). A comprehensive analysis of dynamics is carried out by performing multiple excitations probed in broad Near-Infrared (NIR) regimes. The current study would help collect the knowledge about the phonon and charge carrier dynamics of Bismuth, Tellurium, and Bismuth Telluride films for optical, spintronics, and terahertz applications.
      原文链接:
    • NSTL
    • Elsevier