Browsing by Author "Lu, Y"

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    Crystal growth and thermoelectric properties of CaMn0.98Nb0.02O3-delta
    (Elsevier Science B.V., 2013-08-15) Alfaruq, DS; Aguirre, MH; Otal, EH; Populoh, S; Karvonen, L; Yoon, S; Lu, Y; Deng, G; Ebbinghaus, SG; Weidenkaff, A
    Thermoelectric CaMn0.98Nb0.02O3-delta single crystals were grown from sintered polycrystalline material using the traveling-solvent floating zone (TSFZ) method. The floating-zone furnace was operated at over-pressure using an Ar/O-2 mixture to prevent evaporation during the growth process. Six twin-domain variants were detected with single-crystal X-ray diffraction (XRD) and confirmed by electron diffraction (ED) and high-resolution transmission electron microscopy (HRTEM). The Seebeck coefficient (S) of the single-crystalline material indicates n-type semiconducting behavior. Within 10 K < T < 125 K a negative peak in S is observed, known to be characteristic of antiferromagnetic ordering. The ferromagnetic long-range ordering, expected on the basis of double exchange between Mn4+ and doped Mn3+ species, thus appears to remain suppressed in the single-crystalline material. © 2013, Elsevier Ltd.
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    Identification of the hydrogen utilization pathway for the electrocatalytic hydrogenation of phenol
    (Springer Nature, 2021-08-19) Zhou, L; Zhu, XR; Su, H; Lin, HZ; Lyu, YH; Zhao, X; Chen, C; Zhang, N; Xie, C; Li, YY; Lu, Y; Zheng, JY; Johannessen, B; Jiang, SP; Liu, QH; Li, Y; Zou, Y; Wang, SG
    Electrochemical hydrogenation (ECH) of biomass-derived platform molecules is a burgeoning route for the sustainable utilization of hydrogen. However, the noble-metal-catalyzed ECH of phenolic compounds suffers from intense competition with hydrogen evolution reaction. We prepared PtRh bimetallic nanoparticles dispersed on highly ordered mesoporous carbon nanospheres, which improves the utilization efficiency of adsorbed hydrogen (Had) to ECH in H–UPD region (>0 V vs. RHE). Further analysis reveals (i) the strong overlapping between the d-orbitals of Pt and Rh enhances specific adsorption of phenol; (ii)incorporation of Rh devotes an electronic effect on weakening the alloy–Had interaction to increase the FE of ECH. DFT calculations confirm the selectivity difference and the ECH parallel pathways: cyclohexanol and cyclohexanone are formed via hydrogenation/dehydrogenation of the intermediate *C6H10OH. These findings deepen our fundamental understanding of the ECH process, and cast new light on exploration of highly efficient electrocatalysts for biomass upgrading. © 2019 Springer Nature
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    Novel low-strain layered/rocksalt intergrown cathode for high-energy Li-ion batteries
    (American Chemical Society (ACS), 2023-11-16) Xu, L; Chen, S; Su, Y; Shen, X; He, J; Avdeev, M; Kan, WH; Zhang, B; Fan, W; Chen, L; Cao, D; Lu, Y; Wang, L; Wang, M; Bao, L; Zhang, L; Li, N; Wu, F
    Both layered- and rocksalt-type Li-rich cathode materials are drawing great attention due to their enormous capacity, while the individual phases have their own drawbacks, such as great volume change for the layered phase and low electronic and ionic conductivities for the rocksalt phase. Previously, we have reported the layered/rocksalt intergrown cathodes with nearly zero-strain operation, while the use of precious elements hinders their industrial applications. Herein, low-cost 3d Mn4+ ions are utilized to partially replace the expensive Ru5+ ions, to develop novel ternary Li-rich cathode material Li1+x[RuMnNi]1-xO2. The as-designed Li1.15Ru0.25Mn0.2Ni0.4O2 is revealed to have a layered/rock salt intergrown structure by neutron diffraction and transmission electron microscopy. The as-designed cathode exhibits ultrahigh lithium-ion reversibility, with 0.86 (231.1 mAh g-1) out of a total Li+ inventory of 1.15 (309.1 mAh g-1). The X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectra further demonstrate that the high Li+ storage of the intergrown cathode is enabled by leveraging cationic and anionic redox activities in charge compensation. Surprisingly, in situ X-ray diffraction shows that the intergrown cathode undergoes extremely low-strain structural evolution during the charge-discharge process. Finally, the Mn content in the intergrown cathodes is found to be tunable, providing new insights into the design of advanced cathode materials for high-energy Li-ion batteries. © 2024 American Chemical Society.