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Bin Wang Cheng Tang Hao‐Fan Wang Xiao Chen Rui Cao Qiang Zhang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(4)
A cost‐effective and highly efficient oxygen evolution reaction (OER) electrocatalyst will be significant for the future energy scenario. The emergence of the core–shell heterostructure has invoked new feasibilities to inspire the full potential of non‐precious‐metal candidates. The shells always have a large thickness, affording robust mechanical properties under harsh reaction conditions, which limits the full exposure of active sites with highly intrinsic reactivity and extrinsic physicochemical characters for optimal performance. Herein, a nanosized CoNi hydroxide@hydroxysulfide core–shell heterostructure is fabricated via an ethanol‐modified surface sulfurization method. Such a synthetic strategy is demonstrated to be effective in controllably fabricating a core–shell heterostructure with an ultrathin shell (4 nm) and favorable exposure of active sites, resulting in a moderately regulated electronic structure, remarkably facilitated charge transfer, fully exposed active sites, and a strongly coupled heterointerface for energy electrocatalysis. Consequently, the as‐obtained hydroxide@hydroxysulfide core–shell is revealed as a superior OER catalyst, with a small overpotential of 274.0 mV required for 10.0 mA cm?2, a low Tafel slope of 45.0 mV dec?1, and a favorable long‐term stability in 0.10 M KOH. This work affords fresh concepts and strategies for the design and fabrication of advanced core–shell heterostructures, and thus opens up new avenues for the targeted development of high‐performance energy materials. 相似文献
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Hyeonjin Eom Jaemin Lee Aekachan Pichitpajongkit Morteza Amjadi Jun‐Ho Jeong Eungsug Lee Jung‐Yong Lee Inkyu Park 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(20):4171-4181
Silver nanowire (Ag NW) based transparent electrodes are inherently unstable to moist and chemically reactive environment. A remarkable stability improvement of the Ag NW network film against oxidizing and sulfurizing environment by local electrodeposition of Ni along Ag NWs is reported. The optical transmittance and electrical resistance of the Ni deposited Ag NW network film can be easily controlled by adjusting the morphology and thickness of the Ni shell layer. The electrical conductivity of the Ag NW network film is increased by the Ni coating via welding between Ag NWs as well as additional conductive area for the electron transport by electrodeposited Ni layer. Moreover, the chemical resistance of Ag NWs against oxidation and sulfurization can be dramatically enhanced by the Ni shell layer electrodeposited along the Ag NWs, which provides the physical barrier against chemical reaction and diffusion as well as the cathodic protection from galvanic corrosion. 相似文献
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Wide‐Range Tunable Fluorescence Lifetime and Ultrabright Luminescence of Eu‐Grafted Plasmonic Core–Shell Nanoparticles for Multiplexing
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Jun Zhang Feng Song Zhubing He Yanling Liu Zhanyao Chen Shangxin Lin Ling Huang Wei Huang 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(3):397-404
Wide‐range, well‐separated, and tunable lifetime nanocomposites with ultrabright fluorescence are highly desirable for applications in optical multiplexing such as multiplexed biological detection, data storage, and security printing. Here, a synthesis of tunable fluorescence lifetime nanocomposites is reported featuring europium chelate grafted onto the surface of plasmonic core–shell nanoparticles, and systematically investigated their optical performance. In a single red color emission channel, more than 12 distinct fluorescence lifetime populations with high fluorescence efficiency (up to 73%) are reported. The fluorescence lifetime of Eu‐grafted core–shell nanoparticles exhibits a wider tunable range, possesses larger lifetime interval and is more sensitive to separation distance than that of ordinary Eu‐doping core–shell type. These superior performances are attributed to the unique nanostructure of Eu‐grafed type. In addition, these as‐prepared nanocomposites are used for security printing to demonstrate optical multiplexing applications. The optical multiplexing experiments show an interesting pseudo‐information “a rabbit in a well” and conceal the real message “NKU.” 相似文献
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Pierre Corfdir Oliver Marquardt Ryan B. Lewis Chiara Sinito Manfred Ramsteiner Achim Trampert Uwe Jahn Lutz Geelhaar Oliver Brandt Vladimir M. Fomin 《Advanced materials (Deerfield Beach, Fla.)》2019,31(3)
Phase coherence in nanostructures is at the heart of a wide range of quantum effects such as Josephson oscillations between exciton–polariton condensates in microcavities, conductance quantization in 1D ballistic transport, or the optical (excitonic) Aharonov–Bohm effect in semiconductor quantum rings. These effects only occur in structures of the highest perfection. The 2D semiconductor heterostructures required for the observation of Aharonov–Bohm oscillations have proved to be particularly demanding, since interface roughness or alloy fluctuations cause a loss of the spatial phase coherence of excitons, and ultimately induce exciton localization. Experimental work in this field has so far relied on either self‐assembled ring structures with very limited control of shape and dimension or on lithographically defined nanorings that suffer from the detrimental effects of free surfaces. Here, it is demonstrated that nanowires are an ideal platform for studies of the Aharonov–Bohm effect of neutral and charged excitons, as they facilitate the controlled fabrication of nearly ideal quantum rings by combining all‐binary radial heterostructures with axial crystal‐phase quantum structures. Thanks to the atomically flat interfaces and the absence of alloy disorder, excitonic phase coherence is preserved even in rings with circumferences as large as 200 nm. 相似文献
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Tuning Surface Structure and Strain in Pd–Pt Core–Shell Nanocrystals for Enhanced Electrocatalytic Oxygen Reduction
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Yalin Xiong Hao Shan Zhengnan Zhou Yucong Yan Wenlong Chen Yaxiong Yang Yongfeng Liu He Tian Jianbo Wu Hui Zhang Deren Yang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(7)
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CdS@SiO2 Core–Shell Electroluminescent Nanorod Arrays Based on a Metal–Insulator–Semiconductor Structure
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Chunfeng Wang Dengfeng Peng Jing Zhao Rongrong Bao Tianfeng Li Li Tian Lin Dong Changyu Shen Caofeng Pan 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(41):5734-5740
Enormous advancement has been achieved in the field of one‐dimensional (1D) semiconductor light‐emitting devices (LEDs), however, LEDs based on 1D CdS nanostructures have been rarely reported. The fabrication of CdS@SiO2 core–shell nanorod array LEDs based on a Au–SiO2–CdS metal–insulator–semiconductor (MIS) structure is presented. The MIS LEDs exhibit strong yellow emission with a low threshold voltage of 2.7 V. Electroluminescence with a broad emission ranging from 450 nm to 800 nm and a shoulder peak at 700 nm is observed, which is related to the defects and surface states of the CdS nanorods. The influence of the SiO2 shell thickness on the electroluminescence intensity is systematically investigated. The devices have a high light‐emitting spatial resolution of 1.5 μm and maintain an excellent emission property even after shelving at room temperature for at least three months. Moreover, the fabrication process is simple and cost effective and the MIS device could be fabricated on a flexible substrate, which holds great potential for application as a flexible light source. This prototype is expected to open up a new route towards the development of large‐scale light‐emitting devices with excellent attributes, such as high resolution, low cost, and good stability. 相似文献
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Epitaxial Growth of Lattice‐Mismatched Core–Shell TiO2@MoS2 for Enhanced Lithium‐Ion Storage
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Rui Dai Anqi Zhang Zhichang Pan Abdullah M. Al‐Enizi Ahmed A. Elzatahry Linfeng Hu Gengfeng Zheng 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(20):2792-2799
Core–shell structured nanohybrids are currently of significant interest due to their synergetic properties and enhanced performances. However, the restriction of lattice mismatch remains a severe obstacle for heterogrowth of various core–shells with two distinct crystal structures. Herein, a controlled synthesis of lattice‐mismatched core–shell TiO2@MoS2 nano‐onion heterostructures is successfully developed, using unilamellar Ti0.87O2 nanosheets as the starting material and the subsequent epitaxial growth of MoS2 on TiO2. The formation of these core–shell nano‐onions is attributed to an amorphous layer‐induced heterogrowth mechanism. The number of MoS2 layers can be well tuned from few to over ten layers, enabling layer‐dependent synergistic effects. The core–shell TiO2@MoS2 nano‐onion heterostructures exhibit significantly enhanced energy storage performance as lithium‐ion battery anodes. The approach has also been extended to other lattice‐mismatched systems such as TiO2@MoSe2, thus suggesting a new strategy for the growth of well‐designed lattice‐mismatched core–shell structures. 相似文献
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Design and Synthesis of Spherical Multicomponent Aggregates Composed of Core–Shell,Yolk–Shell,and Hollow Nanospheres and Their Lithium‐Ion Storage Performances
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Micrometer‐sized spherical aggregates of Sn and Co components containing core–shell, yolk–shell, hollow nanospheres are synthesized by applying nanoscale Kirkendall diffusion in the large‐scale spray drying process. The Sn2Co3–Co3SnC0.7–C composite microspheres uniformly dispersed with Sn2Co3–Co3SnC0.7 mixed nanocrystals are formed by the first‐step reduction of spray‐dried precursor powders at 900 °C. The second‐step oxidation process transforms the Sn2Co3–Co3SnC0.7–C composite into the porous microsphere composed of Sn–Sn2Co3@CoSnO3–Co3O4 core–shell, Sn–Sn2Co3@CoSnO3–Co3O4 yolk–shell, and CoSnO3–Co3O4 hollow nanospheres at 300, 400, and 500 °C, respectively. The discharge capacity of the microspheres with Sn–Sn2Co3@CoSnO3–Co3O4 core–shell, Sn‐Sn2Co3@CoSnO3–Co3O4 yolk–shell, and CoSnO3–Co3O4 hollow nanospheres for the 200th cycle at a current density of 1 A g?1 is 1265, 987, and 569 mA h g?1, respectively. The ultrafine primary nanoparticles with a core–shell structure improve the structural stability of the porous‐structured microspheres during repeated lithium insertion and desertion processes. The porous Sn–Sn2Co3@CoSnO3–Co3O4 microspheres with core–shell primary nanoparticles show excellent cycling and rate performances as anode materials for lithium‐ion batteries. 相似文献
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Pernell Dongmo Matthew Hartshorne Thomas Cristiani Michael L. Jablonski Cory Bomberger Dieter Isheim David N. Seidman Mitra L. Taheri Joshua Zide 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(23):4920-4925
Self‐assembled core–shell structured rare‐earth nanoparticles (TbErAs) are observed in a III–V semiconductor host matrix (In0.53Ga0.47As) nominally lattice‐matched to InP, grown via molecular beam epitaxy. Atom probe tomography demonstrates that the TbErAs nanoparticles have a core–shell structure, as seen both in the tomographic atom‐by‐atom reconstruction and concentration profiles. A simple thermodynamic model is created to determine when it is energetically favorable to have core–shell structures; the results strongly agree with the observations. 相似文献
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Programmable Negative Differential Resistance Effects Based on Self‐Assembled Au@PPy Core–Shell Nanoparticle Arrays
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Jianzhong Zheng Junchang Zhang Zi Wang Liubiao Zhong Yinghui Sun Zhiqiang Liang Youyong Li Lin Jiang Xiaodong Chen Lifeng Chi 《Advanced materials (Deerfield Beach, Fla.)》2018,30(35)
The negative differential resistance (NDR) effect observed in conducting polymer/Au nanoparticle composite devices is not yet fully clarified due to the random and disordered incorporation of Au nanoparticles into conducting polymers. It remains a formidable challenge to achieve the sequential arrangement of various components in an optimal manner during the fabrication of Au nanoparticle/conducting polymer composite devices. Here, a novel strategy for fabricating Au nanoparticle/conducting polymer composite devices based on self‐assembled Au@PPy core–shell nanoparticle arrays is demonstrated. The interval between the two Au nanoparticles can be precisely programmed by modulating the thickness of the shell and the size of the core. Programmable NDR is achieved by regulating the spacer between two Au nanoparticles. In addition, the Au/conducting polymer composite device exhibits a reproducible memory effect with read–write–erase characteristics. The sequentially controllable assembly of Au@PPy core–shell nanoparticle arrays between two microelectrodes will simplify nanodevice fabrication and will provide a profound impact on the development of new approaches for Au/conducting polymer composite devices. 相似文献
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Xiaofeng Zhang Xiaocui Li Ruchun Li Yang Lu Shuqin Song Yi Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(42)
Developing highly efficient electrocatalysts with earth abundant elements for oxygen evolution reaction (OER) is a promising way to store light or electrical energy in the form of chemical energy. Here, a new type of electrocatalyst with core–shell carbon/NiCo2O4 double microtubes architecture is successfully synthesized through a hydrothermal method combined with the calcination process with wet tissues as the template and carbon resource. The outer NiCo2O4 nanosheet arrays contain abundant defects, which come from reduction of the carbon in wet tissues. This indicates that carbon is a very excellent defect inducer. The inner carbon microtubes can act as the robust structure skeleton and these core–shell double microtubes provide abundant diffusion channels for oxygen and electrolyte, both of which contribute to improving the stability by avoiding damage to the electrode from produced O2 bubbles and the collapse of the outer NiCo2O4 microtubes. Electrochemical results show that the electrode, core–shell carbon/NiCo2O4 double microtubes loaded on carbon cloth, exhibits prominent electrocatalytic activity with an overpotential of only 168 mV at 10 mA cm?2 and a Tafel slope as low as 57.6 mV dec?1 in 1.0 mol L?1 KOH. This new type of electrocatalyst possesses great potential in water electrolyzers and rechargeable metal–air batteries. 相似文献
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Min Eui Lee Seunggon Lee Jaewon Choi Hyoung‐Joon Jin Seungyong Han Young Soo Yun 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(37)
Anode‐free sodium metal batteries (AF‐SMBs) can deliver high energy and enormous power, but their cycle lives are still insufficient for them to be practical as a power source in modern electronic devices and/or grid systems. In this study, a nanohybrid template based on high aspect‐ratio silver nanofibers and nitrogen‐rich carbon thin layers as a core–shell structure is designed to improve the Coulombic efficiency (CE) and cycling performance of AF‐SMBs. The catalytic nanohybrid templates dramatically reduce the voltage overshooting caused by metal nucleation to one‐fifth that of a bare Al foil electrode (≈6 mV vs ≈30 mV), and high average CE values of >99% are achieved over a wide range of current rates from 0.2 to 8 mA cm?2. Moreover, exceptionally long cycle lives for more than 1600 cycles and an additional 1500 cycles are achieved with a highly stable CE of >99.9%. These results show that AF‐SMBs are feasible with the nanohybrid electrode system. 相似文献
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