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Start Over Author "Liu, Xuehua" Publisher elsevier b.v.
153 results on '"Liu, Xuehua"'

40. MXene@Co hollow spheres structure boosts interfacial polarization for broadband electromagnetic wave absorption.

Author

Zhang, Yan, Liu, Xuehua, Guo, Zhiqiang, Jia, Chenyu, Lu, Feng, Jia, Zirui, and Wu, Guanglei

Subjects
ELECTROMAGNETIC wave absorption, POLARIZATION of electromagnetic waves, ELECTROMAGNETIC waves, MAGNETIC flux leakage, IMPEDANCE matching, MAGNETIC particles
Abstract

• Single-step heat treatment aids template etching and particle growth for successful development of hollow magnetic MXene@Co microspheres. • MXene@Co microspheres show excellent reflection loss capability (−57.32 dB, 2.5 mm) and wide range of absorption bandwidth (5.2 GHz, 2.2 mm). • The superior electromagnetic wave absorption performance is attributed to the constructed hollow structure, enhanced interfacial polarization and optimized magnetic loss. MXene is considered as a candidate for preparing high-performance electromagnetic wave absorbing materials due to its large specific surface area, rich surface modification groups, and unique metal properties. However, the impedance matching problem caused by its high conductivity and easy stacking properties is a limiting factor. In this study, a self-assembling-etching-anchoring growth method was proposed to prepare MXene@Co electromagnetic wave absorbing materials. The hollow structure of MXene microspheres constructed with PMMA as a hard template is conducive to optimizing impedance matching and surface modification. In addition, MXene@Co exhibits abundant heterogeneous interfaces, enhancing the interfacial polarization phenomenon during electromagnetic wave absorption. Meanwhile, the surface-anchored growth of magnetic Co particles forms a magnetic network, which provides a strong magnetic loss capability for the absorber. The hollow structure design significantly enhances the wave absorption performance compared to conventional MXene@Co composites, with a minimum reflection loss of −57.32 dB (effective absorption bandwidth of 5.2 GHz) when the thickness is 2.5 mm (2.2 mm). This work provides a meaningful reference for the design of MXene-based electromagnetic wave absorbing materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2024
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45. Construction of NiCeOx nanosheets-skeleton cross-linked by carbon nanotubes networks for efficient electromagnetic wave absorption.

Author

Huang, Xinmeng, Liu, Xuehua, Zhang, Yan, Zhou, Jixi, Wu, Guanglei, and Jia, Zirui

Subjects
ELECTROMAGNETIC wave absorption, CARBON nanotubes, ELECTROMAGNETIC waves, IMPEDANCE matching
Abstract

• NiCeO x /CNTs were prepared by a simple two-step process. • The defects generated by Ni2+ replacing Ce4+ will lead to dipole polarization, which is beneficial to the electromagnetic wave absorption. • The combination of 2D NiCeO x nanosheets and 1D CNTs complicates the electromagnetic wave absorption mechanism. • The optimal reflection loss reaches -53.2 dB at 1.9 mm. In this work, two-dimensional NiCeO x nanosheet-modified carbon nanotubes (CNTs) composites were prepared by a hydrothermal method. NiCeO x with different morphologies can be formed by adjusting the addition ratio of nickel salt and cerium salt, and the introduction of CNTs in the subsequent synthesis process can effectively prevent the aggregation of NiCeO x nanosheets. Microstructural studies show that hexagonal NiCeO x nanosheets with a size of 100 nm are uniformly intertwined with CNTs. When applied to the attenuation of electromagnetic waves, NiCeO x /CNTs composites exhibit better electromagnetic wave (EMW) absorption performance than pure CNTs and NiCeO x nanosheets due to improved impedance matching and multiple polarization relaxation. At the matching thickness of 1.9 mm, the composite exhibits a minimum reflection loss (RL min) of –53.2 dB and an effective absorption bandwidth (RL < –10 dB) of 5.04 GHz with a thickness of 2.3 mm. These results indicate that the as-prepared NiCeO x /CNTs composites have excellent EMW absorption performance and are expected to be a candidate material for EMW absorption. [ABSTRACT FROM AUTHOR]

Published
2023
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49. Electrospun La0.5Sr0.5Mn0.875Zn0.125O3-δ nano-powders as a single-phase cathode for proton-conducting solid oxide fuel cells.

Author

Liu, Zhaoxiu, Liu, Xuehua, Wu, Guanglei, and Bi, Lei

Subjects
*SOLID oxide fuel cells, *SOLID state proton conductors, *CATHODES, *POWER density
Abstract

The electrospinning technique was employed to prepare the La 0.5 Sr 0.5 Mn 0.875 Zn 0.125 O 3-δ (LSMZn) cathode for proton-conducting solid oxide fuel cells (H–SOFCs). Although the fiber structure can be obtained with the electrospinning technique for the LSMZn precursor, the fiber structure disappeared after the calcination procedure, leading to the formation of fine LSMZn nano-powders. It was found that the electrospun LSMZn can reach a pure phase after firing at 1100 °C, whereas the traditional sol-gel prepared LSMZn required a calcination temperature of 1150 °C. Furthermore, the electrospun LSMZn had a smaller particle size and richer oxygen vacancy than the traditional sol-gel LSMZn. First-principles calculations indicated that the oxygen vacancy-rich surface promoted the cathode reaction. The H–SOFC using the single-phase electrospun LSMZn generated a power density of 1122 mW cm−2 at 700 °C. The performance was not only larger than the sol-gel LSMZn cell reported in this study but also larger than previous H–SOFCs using the single-phase Mn-based cathodes, suggesting the electrospinning technique was an effective method to produce high-performing cathodes for H–SOFCs. [ABSTRACT FROM AUTHOR]

Published
2022
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