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9. From VIB- to VB-Group Transition Metal Disulfides: Structure Engineering Modulation for Superior Electromagnetic Wave Absorption

Author

Cheng, Junye, primary, Jin, Yongheng, additional, Zhao, Jinghan, additional, Jing, Qi, additional, Gu, Bailong, additional, Wei, Jialiang, additional, Yi, Shenghui, additional, Li, Mingming, additional, Nie, Wanli, additional, Qin, Qinghua, additional, Zhang, Deqing, additional, Zheng, Guangping, additional, and Che, Renchao, additional

Published
2023
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21. Building the conformal protection of VB-group VS2laminated heterostructure based on biomass-derived carbon for excellent broadband electromagnetic waves absorption

Author

Wang, Honghan, Zhang, Huibin, Cheng, Junye, Liu, Tingting, Zhang, Deqing, Zheng, Guangping, Zhai, Shangru, and Cao, Maosheng

Abstract

Although VB-Group transition metal disulfides (TMDs) VS2nanomaterials with specific electronic properties and multiphase microstructures have shown fascinating potential in the field of electromagnetic wave (EMW) absorption, the efficient utilization of VS2is limited by the technical bottleneck of its narrow effective absorption bandwidth (EAB) which is attributed to environmental instability and a deficient electromagnetic (EM) loss mechanism. In order to fully exploit the maximal utilization values of VS2nanomaterials for EMW absorption through mitigating the chemical instability and optimizing the EM parameters, biomass-based glucose derived carbon (GDC) like sugar-coating has been decorated on the surface of stacked VS2nanosheets viaa facile hydrothermal method, followed by high-temperature carbonization. As a result, the modulation of doping amount of glucose injection solution (Glucose) could effectively manipulate the encapsulation degree of GDC coating on VS2nanosheets, further implementing the EM response mechanisms of the VS2/GDC hybrids (coupling effect of conductive loss, interfacial polarization, relaxation, dipole polarization, defect engineering and multiple reflections and absorptions) through regulating the conductivity and constructing multi-interface heterostructures, as reflected by the enhanced EMW absorption performance to a great extent. The minimum reflection loss (Rmin) of VS2/GDC hybrids could reach −52.8 dB with a thickness of 2.7 mm at 12.2 GHz. Surprisingly, compared with pristine VS2, the EAB of the VS2/GDC hybrids increased from 2.0 to 5.7 GHz, while their environmental stability was effectively enhanced by virtue of GDC doping. Obviously, this work provides a promising candidate to realize frequency band tunability of EMW absorbers with exceptional performance and environmental stability.

Published
2023
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24. Metal–Organic-Framework-Derived Ball-Flower-like Porous Co 3 O 4 /Fe 2 O 3 Heterostructure with Enhanced Visible-Light-Driven Photocatalytic Activity.

Author

Cao, Qi, Li, Qingqing, Pi, Zhichao, Zhang, Jing, Sun, Li-Wei, Xu, Junzhou, Cao, Yunyi, Cheng, Junye, and Bian, Ye

Subjects
RHODAMINE B, HYDROXYL group, VISIBLE spectra, HETEROJUNCTIONS, PHOTOCATALYSTS, SEWAGE, FERRIC oxide
Abstract

A porous ball-flower-like Co3O4/Fe2O3 heterostructural photocatalyst was synthesized via a facile metal–organic-framework-templated method, and showed an excellent degradation performance in the model molecule rhodamine B under visible light irradiation. This enhanced photocatalytic activity can be attributed to abundant photo-generated holes and hydroxyl radicals, and the combined effects involving a porous structure, strong visible-light absorption, and improved interfacial charge separation. It is notable that the ecotoxicity of the treated reaction solution was also evaluated, confirming that an as-synthesized Co3O4/Fe2O3 catalyst could afford the sunlight-driven long-term recyclable degradation of dye-contaminated wastewater into non-toxic and colorless wastewater. [ABSTRACT FROM AUTHOR]

Published
2022
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27. Nitrogen-Doped Graphene-Encapsulated Nickel–Copper Alloy Nanoflower for Highly Efficient Electrochemical Hydrogen Evolution Reaction

Author

Liu, Bin, Peng, Huiqing, Cheng, Junye, Zhang, Kui, Chen, Da, Shen, Dong, Wu, Shuilin, Jiao, Tianpeng, Kong, Xin, Gao, Qili, Bu, Shuyu, Lee, C.-S., Zhang, Wenjun, Liu, Bin, Peng, Huiqing, Cheng, Junye, Zhang, Kui, Chen, Da, Shen, Dong, Wu, Shuilin, Jiao, Tianpeng, Kong, Xin, Gao, Qili, Bu, Shuyu, Lee, C.-S., and Zhang, Wenjun

Abstract

Development of high-performance and low-cost nonprecious metal electrocatalysts is critical for eco-friendly hydrogen production through electrolysis. Herein, a novel nanoflower-like electrocatalyst comprising few-layer nitrogen-doped graphene-encapsulated nickel–copper alloy directly on a porous nitrogen-doped graphic carbon framework (denoted as Ni x Cu y @ NG-NC) is successfully synthesized using a facile and scalable method through calcinating the carbon, copper, and nickel hydroxy carbonate composite under inert atmosphere. The introduction of Cu can effectively modulate the morphologies and hydrogen evolution reaction (HER) performance. Moreover, the calcination temperature is an important factor to tune the thickness of graphene layers of the Ni x Cu y @ NG-NC composites and the associated electrocatalytic performance. Due to the collective effects including unique porous flowered architecture and the synergetic effect between the bimetallic alloy core and graphene shell, the Ni 3 Cu 1 @ NG-NC electrocatalyst obtained under optimized conditions exhibits highly efficient and ultrastable activity toward HER in harsh environments, i.e., a low overpotential of 122 mV to achieve a current density of 10 mA cm −2 with a low Tafel slope of 84.2 mV dec −1 in alkaline media, and a low overpotential of 95 mV to achieve a current density of 10 mA cm −2 with a low Tafel slope of 77.1 mV dec −1 in acidic electrolyte. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Published
2019

28. Engineering flexible and green electromagnetic interference shielding materials with high performance through modulating WS2nanosheets on carbon fibers

Author

Zhang, Huibin, Liu, Tingting, Huang, Zehao, Cheng, Junye, Wang, Honghan, Zhang, Deqing, Ba, Xuewei, Zheng, Guangping, Yan, Ming, and Cao, Maosheng

Abstract

Flexible and wearable electromagnetic interference (EMI) shielding material is one of the current research focuses in the field of EMI shielding. In this work, for the first time, WS2-carbon fiber (WS2-CF) composites are synthesized by implanting WS2, which has a multiphase structure and a large number of defects, onto the surface of carbon fiber (CF) by using a simple one-step hydrothermal method, and are applied to protect electronic devices from EMI. It is found that the EMI shielding performance of WS2-CF is significantly improved, especially for those at Sand C-bands. At 2 GHz, the EMI shielding efficiency could reach 36.0 dB at a typical thickness of 3.00 mm of the composite, which is much better than that of pure CF (25.5 dB). Besides paving a novel avenue to optimize the electromagnetic shielding performance of flexible and wearable CF-based EMI shielding materials, which have great potential in the practical application for EMI shielding, this work provides a new paradigm for the design and synthesis of EMI shielding materials which have a broad application prospect.

Published
2022
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33. Unconventional Nickel Nitride Enriched with Nitrogen Vacancies as a High-Efficiency Electrocatalyst for Hydrogen Evolution

Author

Liu, Bin, He, Bin, Peng, Huiqing, Zhao, Yufei, Cheng, Junye, Xia, Jing, Shen, Jianhua, Ng, Tsz-Wai, Meng, Xiangmin, Lee, Chun-Sing, Zhang, Wenjun, Liu, Bin, He, Bin, Peng, Huiqing, Zhao, Yufei, Cheng, Junye, Xia, Jing, Shen, Jianhua, Ng, Tsz-Wai, Meng, Xiangmin, Lee, Chun-Sing, and Zhang, Wenjun

Abstract

Development of high-performance and cost-effective non-noble metal electrocatalysts is pivotal for the eco-friendly production of hydrogen through electrolysis and hydrogen energy applications. Herein, the synthesis of an unconventional nickel nitride nanostructure enriched with nitrogen vacancies (Ni3N1-x) through plasma-enhanced nitridation of commercial Ni foam (NF) is reported. The self-supported Ni3N1-x/NF electrode can deliver a hydrogen evolution reaction (HER) activity competitive to commercial Pt/C catalyst in alkaline condition (i.e., an overpotential of 55 mV at 10 mA cm(-2) and a Tafel slope of 54 mV dec(-1)), which is much superior to the stoichiometric Ni3N, and is the best among all nitride-based HER electrocatalysts in alkaline media reported thus far. Based on theoretical calculations, it is further verified that the presence of nitrogen vacancies effectively enhances the adsorption of water molecules and ameliorates the adsorption-desorption behavior of intermediately adsorbed hydrogen, which leads to an advanced HER activity of Ni3N1-x/NF.

Published
2018

36. Magnetic-field-induced dielectric behaviors and magneto-electrical coupling of multiferroic compounds containing cobalt ferrite/barium calcium titanate composite fibers

Author

Zhang, Deqing, primary, Cheng, Junye, additional, Chai, Jixing, additional, Deng, Jiji, additional, Ren, Ran, additional, Su, Yang, additional, Wang, Hao, additional, Ma, Chunqing, additional, Lee, Chun-Sing, additional, Zhang, Wenjun, additional, Zheng, Guang-Ping, additional, and Cao, Maosheng, additional

Published
2018
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50. Spontaneous Orientation Polarization of Anisotropic Equivalent Dipoles Harnessed by Entropy Engineering for Ultra-Thin Electromagnetic Wave Absorber.

Author

Wang H, Xiao X, Zhai S, Xue C, Zheng G, Zhang D, Che R, and Cheng J

Abstract

The synthesis of carbon supporter/nanoscale high-entropy alloys (HEAs) electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes. Electron migration modes within HEAs as manipulated by the electronegativity, valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles. Herein, enlightened by skin-like effect, a reformative carbothermal shock method using carbonized cellulose paper (CCP) as carbon supporter is used to preserve the oxygen-containing functional groups (O·) of carbonized cellulose fibers (CCF). Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·. Meanwhile, the electron migration mode of switchable electron-rich sites promotes the orientation polarization of anisotropic equivalent dipoles. By virtue of the reinforcement strategy, CCP/HEAs composite prepared by 35% molar ratio of Mn element (CCP/HEAs-Mn 2.15 ) achieves efficient electromagnetic wave (EMW) absorption of - 51.35 dB at an ultra-thin thickness of 1.03 mm. The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations, which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices (e.g., ultra-wideband bandpass filter)., (© 2024. The Author(s).)

Published
2024
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