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Three‐Dimensional Nitrogen‐Doped Hierarchical Porous Carbon as an Electrode for High‐Performance Supercapacitors 下载免费PDF全文
Jing Tang Dr. Tao Wang Dr. Rahul R. Salunkhe Prof. Saad M. Alshehri Dr. Victor Malgras Prof. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17293-17298
A facile and sustainable procedure for the synthesis of nitrogen‐doped hierarchical porous carbons with a three‐dimensional interconnected framework (NHPC‐3D) was developed. The strategy, based on a colloidal crystal‐templating method, utilizes nitrogenous dopamine as the precursor due to its unique properties, including self‐polymerization under mild alkaline conditions, coating onto various surfaces, a high carbonization yield, and well‐preserved nitrogen doping after heat treatment. The obtained NHPC‐3D possesses a high surface area of 1056 m2 g?1, a large pore volume of 2.56 cm3 g?1, and a high nitrogen content of 8.2 wt %. The NHPC‐3D is implemented as the electrode material of a supercapacitor and exhibits a specific capacitance as high as 252 F g?1 at a current density of 2 A g?1. The device also shows a high capacitance retention of 75.7 % at a higher current density of 20 A g?1 in aqueous electrolyte due to a sufficient surface area for charge accommodation, reversible pseudocapacitance, and minimized ion‐transport resistance, as a result of the advantageous interconnected hierarchical porous texture. These results showcase NHPC‐3D as a promising candidate for electrode materials in supercapacitors. 相似文献
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One‐Step Synthesis of Self‐Supported Nickel Phosphide Nanosheet Array Cathodes for Efficient Electrocatalytic Hydrogen Generation 下载免费PDF全文
Dr. Xiaoguang Wang Dr. Yury V. Kolen'ko Dr. Xiao‐Qing Bao Prof. Dr. Kirill Kovnir Dr. Lifeng Liu 《Angewandte Chemie (International ed. in English)》2015,54(28):8188-8192
Nickel phosphide is an emerging low‐cost, earth‐abundant catalyst that can efficiently reduce water to generate hydrogen. However, the synthesis of nickel phosphide catalysts usually involves multiple steps and is laborious. Herein, a convenient and straightforward approach to the synthesis of a three‐dimensional (3D) self‐supported biphasic Ni5P4‐Ni2P nanosheet (NS) array cathode is presented, which is obtained by direct phosphorization of commercially available nickel foam using phosphorus vapor. The synthesized 3D Ni5P4‐Ni2P‐NS array cathode exhibits outstanding electrocatalytic activity and long‐term durability toward the hydrogen evolution reaction (HER) in acidic medium. The fabrication procedure reported here is scalable, showing substantial promise for use in water electrolysis. More importantly, the approach can be readily extended to synthesize other self‐supported transition metal phosphide HER cathodes. 相似文献
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Solution‐Liquid‐Solid Synthesis of Hexagonal Nickel Selenide Nanowire Arrays with a Nonmetal Catalyst 下载免费PDF全文
Dr. Kun Xu Hui Ding Kaicheng Jia Xiuli Lu Pengzuo Chen Tianpei Zhou Han Cheng Si Liu Prof. Changzheng Wu Prof. Yi Xie 《Angewandte Chemie (International ed. in English)》2016,55(5):1710-1713
Inorganic nanowire arrays hold great promise for next‐generation energy storage and conversion devices. Understanding the growth mechanism of nanowire arrays is of considerable interest for expanding the range of applications. Herein, we report the solution‐liquid‐solid (SLS) synthesis of hexagonal nickel selenide nanowires by using a nonmetal molecular crystal (selenium) as catalyst, which successfully brings SLS into the realm of conventional low‐temperature solution synthesis. As a proof‐of‐concept application, the NiSe nanowire array was used as a catalyst for electrochemical water oxidation. This approach offers a new possibility to design arrays of inorganic nanowires. 相似文献
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In Situ Growth of Hierarchical SnO2 Nanosheet Arrays on 3D Macroporous Substrates as High‐Performance Electrodes 下载免费PDF全文
Dr. Xinyu Zhao Dr. Bing Liu Prof. Changwen Hu Prof. Minhua Cao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):467-473
Finding out how to overcome the self‐aggregation of nanostructured electrode materials is a very important issue in lithium‐ion battery technology. Herein, by an in situ construction strategy, hierarchical SnO2 nanosheet architectures have been fabricated on a three‐dimensional macroporous substrate, and thus the aggregation of the SnO2 nanosheets was effectively prevented. The as‐prepared hierarchical SnO2 nanoarchitectures on the nickel foam can be directly used as an integrated anode for lithium‐ion batteries without the addition of other ancillary materials such as carbon black or binder. In view of their apparent advantages, such as high electroactive surface area, ultrathin sheet, robust mechanical strength, shorter ion and electron transport path, and the specific macroporous structure, the hierarchical SnO2 nanosheets exhibit excellent lithium‐storage performance. Our present growth approach offers a new technique for the design and synthesis of metal oxide hierarchical nanoarrays that are promising for electrochemical energy‐storage electrodes without carbon black and binder. 相似文献
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Zhaolin Na Gang Huang Fei Liang Dongming Yin Prof. Limin Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(34):12081-12087
The preparation of novel one‐dimensional core–shell Fe/Fe2O3 nanowires as anodes for high‐performance lithium‐ion batteries (LIBs) is reported. The nanowires are prepared in a facile synthetic process in aqueous solution under ambient conditions with subsequent annealing treatment that could tune the capacity for lithium storage. When this hybrid is used as an anode material for LIBs, the outer Fe2O3 shell can act as an electrochemically active material to store and release lithium ions, whereas the highly conductive and inactive Fe core functions as nothing more than an efficient electrical conducting pathway and a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium ions. The core–shell Fe/Fe2O3 nanowire maintains an excellent reversible capacity of over 767 mA h g?1 at 500 mA g?1 after 200 cycles with a high average Coulombic efficiency of 98.6 %. Even at 2000 mA g?1, a stable capacity as high as 538 mA h g?1 could be obtained. The unique composition and nanostructure of this electrode material contribute to this enhanced electrochemical performance. Due to the ease of large‐scale fabrication and superior electrochemical performance, these hybrid nanowires are promising anode materials for the next generation of high‐performance LIBs. 相似文献
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Bing Ding Dr. Changzhou Yuan Laifa Shen Guiyin Xu Ping Nie Prof. Xiaogang Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):1013-1019
A three‐dimensional (3D) hierarchical carbon–sulfur nanocomposite that is useful as a high‐performance cathode for rechargeable lithium–sulfur batteries is reported. The 3D hierarchically ordered porous carbon (HOPC) with mesoporous walls and interconnected macropores was prepared by in situ self‐assembly of colloidal polymer and silica spheres with sucrose as the carbon source. The obtained porous carbon possesses a large specific surface area and pore volume with narrow mesopore size distribution, and acts as a host and conducting framework to contain highly dispersed elemental sulfur. Electrochemical tests reveal that the HOPC/S nanocomposite with well‐defined nanostructure delivers a high initial specific capacity up to 1193 mAh g?1 and a stable capacity of 884 mAh g?1 after 50 cycles at 0.1 C. In addition, the HOPC/S nanocomposite exhibits high reversible capacity at high rates. The excellent electrochemical performance is attributed exclusively to the beneficial integration of the mesopores for the electrochemical reaction and macropores for ion transport. The mesoporous walls of the HOPC act as solvent‐restricted reactors for the redox reaction of sulfur and aid in suppressing the diffusion of polysulfide species into the electrolyte. The “open” ordered interconnected macropores and windows facilitate transportation of electrolyte and solvated lithium ions during the charge/discharge process. These results show that nanostructured carbon with hierarchical pore distribution could be a promising scaffold for encapsulating sulfur to approach high specific capacity and energy density with long cycling performance. 相似文献
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Weiqiang Zhou Wei Liang Teo Dongdong Wang Gancheng Zuo Deblin Jana Cheng Qian Hou Wang Jiawei Liu Yanli Zhao 《化学:亚洲杂志》2020,15(16):2513-2519
Development of heterogeneous catalysts has attracted increasing attention, owing to their remarkable catalytic performance and recyclability. Herein, we report well‐developed heterogeneous catalysts with a three‐dimensional ordered hierarchical structure, constructed from nickel or cobalt nanoparticles embedded in porous carbon. The obtained catalysts were fully characterized by several techniques. On account of the uniform distribution of metal nanoparticles in the porous carbon matrix and large diffusion channels that allow for effective mass transport, the catalysts exhibited superior catalytic performance for styrene epoxidation reaction. In particular, the catalysts showed good catalytic activity, high selectivity and excellent recyclability toward the styrene epoxidation. Thus, this facile approach developed allows for fabricating advanced heterogeneous catalysts with high catalytic activities for useful practical applications. 相似文献
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Earth‐Abundant Oxygen Evolution Catalysts Coupled onto ZnO Nanowire Arrays for Efficient Photoelectrochemical Water Cleavage 下载免费PDF全文
Chaoran Jiang Dr. Savio J. A. Moniz Dr. Majeda Khraisheh Dr. Junwang Tang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12954-12961
ZnO has long been considered as a model UV‐driven photoanode for photoelectrochemical water splitting, but its performance has been limited by fast charge‐carrier recombination, extremely poor stability in aqueous solution, and slow kinetics of water oxidation. These issues were addressed by applying a strategy of optimization and passivation of hydrothermally grown 1D ZnO nanowire arrays. The length and diameter of bare ZnO nanowires were optimized by varying the growth time and precursor concentration to achieve optimal photoelectrochemical performance. The addition of earth‐abundant cobalt phosphate (Co‐Pi) and nickel borate (Ni‐B) oxygen evolution catalysts onto ZnO nanowires resulted in substantial cathodic shifts in onset potential to as low as about 0.3 V versus the reversible hydrogen electrode (RHE) for Ni‐B/ZnO, for which a maximum photocurrent density of 1.1 mA cm?2 at 0.9 V (vs. RHE) with applied bias photon‐to‐current efficiency of 0.4 % and an unprecedented near‐unity incident photon‐to‐current efficiency at 370 nm. In addition the potential required for saturated photocurrent was dramatically reduced from 1.6 to 0.9 V versus RHE. Furthermore, the stability of these ZnO nanowires was significantly enhanced by using Ni‐B compared to Co‐Pi due to its superior chemical robustness, and it thus has additional functionality as a stable protecting layer on the ZnO surface. These remarkable enhancements in both photocatalytic activity and stability directly address the current severe limitations in the use of ZnO‐based photoelectrodes for water‐splitting applications, and can be applied to other photoanodes for efficient solar‐driven fuel synthesis. 相似文献
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Dan Zhang Dr. Wenping Sun Zhihui Chen Yu Zhang Dr. Wenbin Luo Prof. Yinzhu Jiang Prof. Shi Xue Dou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):18060-18065
Two‐dimensional (2D) nanomaterials are one of the most promising types of candidates for energy‐storage applications due to confined thicknesses and high surface areas, which would play an essential role in enhanced reaction kinetics. Herein, a universal process that can be extended for scale up is developed to synthesise ultrathin cobalt‐/nickel‐based hydroxides and oxides. The sodium and lithium storage capabilities of Co3O4 nanosheets are evaluated in detail. For sodium storage, the Co3O4 nanosheets exhibit excellent rate capability (e.g., 179 mA h g?1 at 7.0 A g?1 and 150 mA h g?1 at 10.0 A g?1) and promising cycling performance (404 mA h g?1 after 100 cycles at 0.1 A g?1). Meanwhile, very impressive lithium storage performance is also achieved, which is maintained at 1029 mA h g?1 after 100 cycles at 0.2 A g?1. NiO and NiCo2O4 nanosheets are also successfully prepared through the same synthetic approach, and both deliver very encouraging lithium storage performances. In addition to rechargeable batteries, 2D cobalt‐/nickel‐based hydroxides and oxides are also anticipated to have great potential applications in supercapacitors, electrocatalysis and other energy‐storage‐/‐conversion‐related fields. 相似文献
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Ultrathin WS2 Nanoflakes as a High‐Performance Electrocatalyst for the Hydrogen Evolution Reaction 下载免费PDF全文
Dr. Liang Cheng Wenjing Huang Qiufang Gong Changhai Liu Prof. Zhuang Liu Prof. Yanguang Li Prof. Hongjie Dai 《Angewandte Chemie (International ed. in English)》2014,53(30):7860-7863
Much has been done to search for highly efficient and inexpensive electrocatalysts for the hydrogen evolution reaction (HER), which is critical to a range of electrochemical and photoelectrochemical processes. A new, high‐temperature solution‐phase method for the synthesis of ultrathin WS2 nanoflakes is now reported. The resulting product possesses monolayer thickness with dimensions in the nanometer range and abundant edges. These favorable structural features render the WS2 nanoflakes highly active and durable catalysts for the HER in acids. The catalyst exhibits a small HER overpotential of approximately 100 mV and a Tafel slope of 48 mV/decade. These ultrathin WS2 nanoflakes represent an attractive alternative to the precious platinum benchmark catalyst and rival MoS2 materials that have recently been heavily scrutinized for the electrocatalytic HER. 相似文献
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An electrochromic device with the as‐obtained nanoporous NiO /ZnO nanoarray as a working electrode was constructed and assembled. The nanoporous NiO/ZnO nanoarray film with a three‐dimensional structure was prepared on indium tin oxide (ITO) glass substrate through a two‐step route that combined chemical bath deposition method with a hydrothermal method. The nanoporous NiO/ZnO nanoarray electrode reveals a noticeable improvement in electrochromism compared with that of nanoporous NiO alone, including higher optical modulation (81 %), higher coloration efficiency (78.5 cm2 C?1), faster response times (2.6 and 9.7 s for coloring and bleaching, respectively), and favorable durability performance. Such enhancements are mainly attributed to the three‐dimensional structures of nanoporous NiO coated on ZnO nanoarray, namely, 1) the uniform hexagonal ZnO nanoarray loads more nanoporous NiO, 2) nanoporous NiO cross‐linked with ZnO nanorods provides a loose interspace morphology, 3) stronger adhesion between ZnO nanorods and ITO covered with ZnO seed, 4) core–shell and cross‐linked structures promote electrolyte infiltration, and 5) appropriate band gaps improve charge transfer. 相似文献
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Dr. Samuel Dessources Dr. Claudia Morais Dr. Têko W. Napporn Prof. K. Boniface Kokoh 《Chemphyschem》2016,17(23):3964-3973
Hydrogen oxidation and evolution reactions (HOR and HER) are studied on PtxNi1?x/C materials synthesized by the bromide anion exchange method. Physicochemical characterization shows that this surfactant‐free method enables the preparation of well‐dispersed and effective catalysts for the processes involved in the anode of H2/O2 fuel cells (HOR) and the cathode of water electrolyzers (HER). The Pt‐based materials are modified with different Ni contents to decrease the amount of costly precious metal in the electrode materials. These modified Pt‐based materials are found to be electroactive for both reactions without additional overpotential. Kinetic parameters such as the Tafel slope, exchange (j0) and kinetic current densities, and the rate‐determining steps of the reaction mechanisms are determined for each Pt–Ni catalyst and compared to those obtained at the Pt/C surface in alkaline medium. The high j0 values that are obtained indicate a probable contribution of the surface structure of the catalysts due to their roughness and the presence of oxygenated Ni species even at low potentials. 相似文献
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Graphitic Carbon Nitride Nanosheet–Carbon Nanotube Three‐Dimensional Porous Composites as High‐Performance Oxygen Evolution Electrocatalysts 下载免费PDF全文
Dr. Tian Yi Ma Prof. Sheng Dai Prof. Mietek Jaroniec Prof. Shi Zhang Qiao 《Angewandte Chemie (International ed. in English)》2014,53(28):7281-7285
A new class of highly efficient oxygen evolution catalysts has been synthesized through the self‐assembly of graphitic carbon nitride nanosheets and carbon nanotubes, driven by π–π stacking and electrostatic interactions. Remarkably, the catalysts exhibit higher catalytic oxygen evolution activity and stronger durability than Ir‐based noble‐metal catalysts and display the best performance among the reported nonmetal catalysts. This good result is attributed to the high nitrogen content and the efficient mass and charge transfer in the porous three‐dimensional nanostructure. 相似文献
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《化学:亚洲杂志》2017,12(22):2967-2972
The design of high‐performance catalysts for hydrogen generation is highly desirable for the upcoming hydrogen economy. Herein, we report the colloidal synthesis of nanocuboid Ni2P by the thermal decomposition of nickel chloride hexahydrate (NiCl2 ⋅ 6 H2O) and trioctylphosphine. The obtained nanocuboid Ni2P was characterized by using powder X‐ray diffraction, transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy. For the first time, the as‐synthesized nanocuboid Ni2P is used as a bifunctional catalyst for hydrogen generation from the hydrolysis of ammonia borane and electrocatalytic hydrogen evolution. Owing to the strong synergistic electronic effect between Ni and P, the as‐synthesized Ni2P exhibits catalytic performance that is superior to its counterpart without P doping. 相似文献
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Three Dimensionally Ordered Mesoporous Carbon as a Stable,High‐Performance Li–O2 Battery Cathode 下载免费PDF全文
Jin Xie Xiahui Yao Qingmei Cheng Ian P. Madden Paul Dornath Chun‐Chih Chang Prof. Dr. Wei Fan Prof. Dr. Dunwei Wang 《Angewandte Chemie (International ed. in English)》2015,54(14):4299-4303
Enabled by the reversible conversion between Li2O2 and O2, Li–O2 batteries promise theoretical gravimetric capacities significantly greater than Li‐ion batteries. The poor cycling performance, however, has greatly hindered the development of this technology. At the heart of the problem is the reactivity exhibited by the carbon cathode support under cell operation conditions. One strategy is to conceal the carbon surface from reactive intermediates. Herein, we show that long cyclability can be achieved on three dimensionally ordered mesoporous (3DOm) carbon by growing a thin layer of FeOx using atomic layer deposition (ALD). 3DOm carbon distinguishes itself from other carbon materials with well‐defined pore structures, providing a unique material to gain insight into processes key to the operations of Li–O2 batteries. When decorated with Pd nanoparticle catalysts, the new cathode exhibits a capacity greater than 6000 mAh gcarbon?1 and cyclability of more than 68 cycles. 相似文献