期刊：
Results in Physics,2021年22:103893 ISSN：2211-3797
通讯作者：
Shiliang Wang
作者机构：
[Gao, Yangyang; Zhen, Xing; Hou, Lizhen] Hunan Normal Univ, Sch Phys & Elect, Changsha 410081, Peoples R China.;[Wang, Shiliang; Kuang, Daitao; Deng, Lianwen; Luo, Heng; Liu, Linlin] Cent South Univ, Sch Phys & Elect, Changsha 410083, Peoples R China.;[Chen, Chuansheng] Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Peoples R China.
通讯机构：
[Shiliang Wang] S;School of Physics and Electronics, Central South University, Changsha 410083, China
关键词：
Core-shell nanoparticles;Metal organic chemical vapor deposition;Thermal stability;Magnetic property;Magnetic alloy
摘要：
Magnetic alloy-C core-shell nanoparticles with tunable elemental components are highly expected for their controllable magnetic, catalytic, and electromagnetic properties, and high air stability. Here we present a simple one-step metal organic chemical vapor deposition for the synthesis of CoNi-C core-shell nanoparticles with tunable Co/Ni molar ratio. The as-synthesized nanoparticles have core sizes of 5-50 nm, shell thicknesses of similar to 5 nm, and tunable Co/Ni molar ratio determined by the molar ratio of Co(acac)(3)/Ni(acac)(2) used in the precursor. The core-shell nanoparticles are very stable in ambient atmosphere at the temperature below 200 degrees C, and exhibit a slight oxidation in the temperature range of 200-400 degrees C. The core-shell nanoparticles with Co/Ni molar ratios of 1.27:1, 0.64:1, and 0.30:1 exhibit saturation magnetization values of 41, 31, and 24 emu/g, and coercivity values of 483, 346, and 362 Oe, respectively. It is demonstrated that the microwave absorption parameters of the as-synthesized nanoparticles can be tuned by the Co/Ni molar ratio, which provides a practical strategy to regulate the microwave absorption properties of nanostructured absorbers.
摘要：
The mechanisms responsible for the dielectric response of C-based microwave absorbers remain a long-standing theoretical question. Uncovering these mechanisms is critical to enhance their microwave absorption performance. To determine how different C forms alter the dielectric response of C-based absorbers, FeNi-capped carbon nanotubes (FeNi-CNTs) and FeNi-cored carbon nanoparticles (FeNi-CNPs) are synthesized, and a comparative study of their dielectric responses is then carried out in this study. The as-synthesized FeNi-CNTs and FeNi-CNPs have similar magnetic properties and complex permeabilities, but differ in complex permittivities. It is shown that FeNi-CNTs have a much stronger dielectric loss than FeNi-CNPs. At a thickness of 2.8 mm, a low optimal reflection loss of -32.2 dB and a broad effective absorption bandwidth of 8.0 GHz are achieved for FeNi-CNTs. Meanwhile, equivalent circuit models reveal that the CNT network of the FeNi-CNTs could introduce an electrical inductance that can effectively improve its dielectric loss capability. This study demonstrates that designing a composite with a tailored C form and composition is a successful strategy for tuning its microwave absorption performance. Furthermore, the equivalent circuit modeling is an effective tool for analyzing the dielectric response of the microwave absorbers, as is expected to be applicable for other metal-C composites.
摘要：
A pomegranate-like ZnMn2O4 sphere electrode material was prepared via co-precipitation and calcination method, and was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and electrochemical workstation. Experimental results display that the calcination temperature has a large influence on the morphology of ZnMn2O4 porous microsphere. When the annealed temperature is 600 degrees C, ZnMn2O4 porous microsphere possesses the best electrochemical performance, in which the specific capacitance reaches 447 F/g at a current density of 1 A/g. The excellent electrochemical performances are mainly attributed to the porous structure and large specific surface area, indicated that the pomegranate-like ZnMn2O4 porous microsphere has a potential application in electrode material of supercapacitor. (C) 2020 Elsevier B.V. All rights reserved.
摘要：
It is essential for multifunctional asphalt to develop the new nanostructures with high photocatalytic activity in order to endow asphalt with the self-cleaning ability of contamination. Multi-walled carbon nanotubes/ZnO (MWNTs/ZnO) composites were synthesized based on microwave irradiation and their structure and photocatalytic properties were investigated. The experimental results showed that MWNTs/ZnO powder with different morphologies was attained such as cone-shaped, floral-patterned and fusiform structures. The as-obtained MWNTs/ZnO composites were proved to possess quite high catalytic activities for degradation of methyl orange (MO). Especially, the floral-patterned MWNTs/ZnO composites displayed better photocatalytic performance than the other composites indicating that the resultant MVVNTs/ZnO composites can be used as photocatalysts without any additional treatment.
摘要：
Despite that a variety of carbon materials have been explored for electrochemical energy storage, rationally design the carbon structure for efficient electrons transfer and ions diffusion to further improve its performance is still a challenge. In this report, a novel three-dimension hybrid carbon material (NCNF/RGO) prepared from reduced graphene oxide (RGO) and N-doped carbon nanoflower (NCNF) consisting of carbon nanosheets has been fabricated by a hydrothermal treatment and freeze-drying method, and demonstrated as supercapacitor's electrode. Benefiting from such structure design with thin porous nanosheets, interworking mesoporous channel and RGO wrapping for efficient electrolyte ions diffusion and electrons transfer, the resulting hybrid electrode displays high specific capacitance of 344 F g(-1) at a current density of 0.5 A g(-1) and 179 F g(-1) even at 50 A g(-1) in the KOH electrolyte, and 152 F g(-1) at 1 A g(-1) in the ionic liquid electrolyte with a wide voltage range. Significantly, the assembled symmetric supercapacitor using the NCNF/RGO as electrode materials reaches a large energy density of 84.2Wh Kg(-1) at a power density of 1.0 kWkg(-1), indicating its great potential application. (c) 2019 Elsevier Ltd. All rights reserved.
摘要：
A flower-like hierarchical graphene oxide/ZnO (GO/ZnO) macrospheres were fabricated via a low-temperature hydrothemal method, and their photocatalytic performance was tested under natural sunlight and darkness. The resultant GO/ZnO sample displays unique hierarchical macrosphere with diameters in the range of 2–3 μm. The photocatalytic activity of the GO/ZnO microspheres depended on GO, and GO/ZnO macrosphere containing 0.37% GO exhibited very high photocatalytic activity under natural sunlight irradiation and without stirring. Furthermore, GO/ZnO macrospheres possessed good photocatalytic activity under darkness, in which its removal rate of RhB is approximately 5.5 times as many as pure ZnO macrospheres. The enhancement in photocatalytic activity originates from the superior electrical properties of GO, facilitating to transfer the photogenerated electrons and decrease the recombination of photogenerated charge carriers.
摘要：
To improve the photocatalytic activity and endow graphene oxide/TiO2 (GO/TiO2) hybrid with the optical storage ability, WO3 quantum dots (WO3 QDs) were used to modify GO/TiO2 hybrids by sol-gel method, and then the resultant WO3 QDs-GO/TiO2 hybrids were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Experimental results show that WO3 QDs can significantly ameliorate the photocatalytic performance of GO/TiO2 hybrids under visible light, which the reaction rate of WO3 QDs-GO/TiO2 hybrids is about 17 times as much as that of GO/TiO2 hybrids. What's more, WO3 QDs-GO/TiO2 hybrids possess optical memory performance.
作者机构：
[Yu, Weiwei; Chao, Zisheng; Liu, Xiaoyan; Chen, Chuansheng; Mei, Wei] Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Hunan, Peoples R China.;[Chen, Xi'an] Wenzhou Univ, Zhejiang Key Lab Carbon Mat, Coll Chem & Mat Engn Wenzhou Univ, Wenzhou 325027, Peoples R China.;[Tsang, Yuenhong; Zeng, Longhui] Hong Kong Polytech Univ, Dept Appl Phys, Hong Kong 999077, Hong Kong, Peoples R China.
通讯机构：
[Chen, Chuansheng] C;[Chen, Xi'an] W;Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Hunan, Peoples R China.;Wenzhou Univ, Zhejiang Key Lab Carbon Mat, Coll Chem & Mat Engn Wenzhou Univ, Wenzhou 325027, Peoples R China.
摘要：
Graphene oxide (GO) has been the focus of attention as it can enhance the photocatalytic activity of semiconductors due to its large specific surface area and remarkable optical and electronic properties. However, the enhancing effect is not ideal because of its easy self-agglomeration and low electronic conductivity. To improve the enhancing effect of GO for ZnO, three-dimensional GO/MoS2 composite carriers (3D GOM) were prepared by electrostatic interactions and then, Mg-doped ZnO nanoparticles (MZ) were supported on the surface of 3D GOM by utilizing the layer-by-layer assembly method. Compared with GO/Mg-ZnO composite (GOMZ), the resultant three-dimensional GO/MoS2/Mg-ZnO composite (GOMMZ) exhibited excellent photocatalytic performance due to the effective synergistic effect between GO and MoS2 sheet, and its degradation rate was nearly 100% within 120 min of exposure to visible light; this degradation rate was nearly 8 times higher than that of the GOMZ composite. Moreover, the introduction of the MoS2 sheet intensified the photocurrent density of the GOMZ composite and endowed it with optical memory ability.
摘要：
A versatile approach was developed to synthesize graphene oxide/Bi2O3 nanohybrids by organic electrolyte-assisted coprecipitation method. The structure, morphology and photocatalytic property of GO/Bi2O3 hybrids were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-vis spectrophotometer, respectively. Experimental results showed that the tadpole-like MoO2-Bi2O3 hybrids and WO3-Bi2O3 nanorods were covered on the graphene sheets, respectively. Furthermore, the resultant GO/Bi2O3 hybrids possessed strong adsorption ability and high photocatalytic activity for Rhodamine B (RhB).
摘要：
To improve the photocatalytic activity and electrochemical performance, WO3 quantum dots (WO3 QDs) were used to modify GO/TiO2 (GOT) composites by sol-gel method, and the resultant GO/WO3/TiO2 (GOWT) composites were characterized. Experimental results show that WO3 QDs can enhance photocatalytic activity of GOT composite under visible light, in which its degraded efficiency for Rhodamine B (RhB) is about three times as that of GOT composite. Furthermore, GOWT composite possess excellent electrochemical performance. The enhanced photocatalytic activity is attributed to the special band gap structure and excellent electrochemical properties of WO3 QDs.
