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111.
Semiconductor and Metallic Core–Shell Nanostructures: Synthesis and Applications in Solar Cells and Catalysis 下载免费PDF全文
Dr. Mee Rahn Kim Dr. Zhenhe Xu Dr. Guozhu Chen Prof. Dr. Dongling Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(36):11256-11275
Nano‐heterostructures have attracted great attention due to their extraordinary properties beyond those of their single‐component counterparts. This review focuses on a specific type of hybrid structures: core–shell structures. In particular, we present and discuss the recent wet‐chemical synthesis approaches for semiconductor and metallic core–shell nanostructures, and their relevant properties and potential applications in photovoltaics and catalysis, respectively. 相似文献
112.
采用B3LYP/DZP++的方法研究了第一水化层作用和连续化处理的水溶剂作用对鸟嘌呤-胞嘧啶(GC)碱基对和腺嘌呤-胸腺嘧啶(AT)碱基对质子转移反应的影响. GC和AT碱基对在连续化水溶剂作用下,均发生单质子转移(SPT1)和分步的双质子转移(DPT),而在第一水化层5 个水分子的作用下(GC·5H2O,AT·5H2O)或同时考虑第一水化层作用和连续化水溶剂作用(GC·5H2O+PCM,AT·5H2O+PCM)时,GC和AT碱基对的质子转移均只得到单质子转移反应(SPT1). 单质子转移过程中的活化能变化情况表明:第一水化层对GC和AT碱基对结构和质子转移影响较大,水环境对碱基对的作用主要发生在第一水化层. 相似文献
113.
Control of the Electronic Ground State on an Electron‐Transfer Copper Site by Second‐Sphere Perturbations 下载免费PDF全文
Marcos N. Morgada Dr. Luciano A. Abriata Ulises Zitare Dr. Damian Alvarez‐Paggi Prof. Daniel H. Murgida Prof. Alejandro J. Vila 《Angewandte Chemie (International ed. in English)》2014,53(24):6188-6192
The CuA center is a dinuclear copper site that serves as an optimized hub for long‐range electron transfer in heme–copper terminal oxidases. Its electronic structure can be described in terms of a σu* ground‐state wavefunction with an alternative, less populated ground state of πu symmetry, which is thermally accessible. It is now shown that second‐sphere mutations in the CuA containing subunit of Thermus thermophilus ba3 oxidase perturb the electronic structure, which leads to a substantial increase in the population of the πu state, as shown by different spectroscopic methods. This perturbation does not affect the redox potential of the metal site, and despite an increase in the reorganization energy, it is not detrimental to the electron‐transfer kinetics. The mutations were achieved by replacing the loops that are involved in protein–protein interactions with cytochrome c, suggesting that transient protein binding could also elicit ground‐state switching in the oxidase, which enables alternative electron‐transfer pathways. 相似文献
114.
分别以硼氨配合物和硼氢化钠为还原剂合成了核壳结构的Cu@CoW三元合金催化剂和非核壳结构的CuCoW三元合金催化剂,25℃下,Cu0.4@Co0.5W0.1三元合金催化剂对于硼氨配合物水解反应的TOF(转换频率)值达到0.369 0 molH2·molcat-1·s-1,明显高于非核壳结构的Cu0.4Co0.5W0.1催化剂,接近Pt、Pd等贵金属的催化活性,反应的活化能为49 kJ·mol-1。与非核壳结构的CuCoW合金相比,核壳结构的Cu@CoW三元合金催化剂的催化性能及稳定性均有明显提高。 相似文献
115.
Yanbin Shen Yahao Li Shengjue Deng Guoxiang Pan Qinqin Xiong Xiaokun Ding Yangfan Lu Qi Liu Xinhui Xia Xiuli Wang Jiangping Tu 《中国化学快报》2020,31(3):846-850
High-perfo rmance anodes of sodium ion batteries(SIBs)largely depends on rational architecture design and binder-free smart hybridization.Herein,we report TiC/C core/shell nanowires arrays prepared by a one-step chemical vapor deposition(CVD)method and apply it as the anode of SIBs for the first time.The conductive TiC core is intimately decorated with carbon shell.The as-obtained TiC/C nanowires are homogeneously grown on the substrate and show core/shell heterostructure and porous architecture with high electronic conductivity and reinforced stability.Owing to these merits,the TiC/C electrode displays good rate performance and outstanding cycling performance with a capacity of 135.3 mAh/g at 0.1 A/g and superior capacity retention of 90.14%after 1000 cycles at 2 A/g.The reported strategy would provide a promising way to construct binder-free arrays electrodes for sodium ion storage. 相似文献
116.
Fei Lv Jianfeng Fan Jiarong Huang Liming Cao Xuesong Yan Ling Ge Saifudin Abubakar Yukun Chen 《先进技术聚合物》2020,31(10):2161-2171
As the most successful commercialized thermoplastic vulcanizates (TPVs), polypropylene (PP)/ethylene propylene rubber (EPDM) TPVs exhibit poor oil resistance. In this work, we prepared PP/EPDM/butadiene acrylonitrile rubber (NBR) ternary TPVs with good oil resistance using core‐shell dynamic vulcanization. According to the theoretical analysis of the spreading coefficient and the transmission electron microscopy results, the rubber phases exhibited a special core‐shell structure, in which the cross‐linkedNBR‐core was encapsulated by the EPDM‐shell. The core‐shell structure effectively improved the interfacial compatibility between PP and NBR phase as the EPDM‐shell could avoid the direct contact of them, thus improving the mechanical properties of the TPVs. For example, the PP/EPDM/NBR (40/30/30) ternary TPV showed enhanced tensile strength of 12.57 MPa, compared with 10.71 MPa of PP/EPDM (40/60) TPV and 11.11 MPa of PP/NBR (40/60) TPV, respectively. Moreover, the oil resistance of the TPVs was also improved. Compared with PP/EPDM TPV, the change rates in mass, volume, tensile strength and elongation at break of PP/EPDM/NBR TPV after oil immersion decreased by 42.18%, 48.69%, 52.68% and 28.77%, respectively. 相似文献
117.
In order to improve the performance of inorganic/organic composites, aluminum trihydroxide (ATH) core composites with a styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (MAH‐g‐SEBS) shell phase, and P‐N flame retardant as a synergistic agent, were prepared through an interface design. The effects of polyethylene glycol (PEG) content on the interfacial interaction, flame retardancy, thermal properties, and mechanical properties of high‐density polyethylene (HDPE)/ATH composites were investigated by small angle X‐ray diffraction, rotational rheometer, limiting oxygen index, thermogravimetric analysis (TGA), and tensile testing. The ATH synergistic effects of P‐N flame‐retardant improved the combustion performance of HDPE/ATH/PEG(3%)/MAH‐g‐SEBS/P‐N (abbreviated as HDPE/MH3/M‐g‐S/P‐N) composite by forming more carbon layer, increased the elongation at break from 21% to 558% compared to HDPE/ATH, and increased the interface thickness from 0.447 to 0.891 nm. SEM results support the compatibility of ATH with HDPE increased and the interfacial effect was enhanced. TGA showed the maximum decomposition temperature of the two stages and the yield of the residue at high temperature increased first and then decreased with the increase of PEG content. Rheological behavior showed the storage modulus, complex viscosity, and the relaxation time initially increased and then decreased with the increase of PEG content indicating PEG, M‐g‐S, and ATH powder gradually formed a partial coating, then a full coating, and finally an over‐coated core‐shell structured model. 相似文献
118.
Jinze Liu Yating Wang Hao Jiang Haibo Jiang Xiaodong Zhou Yuhang Li Chunzhong Li 《化学:亚洲杂志》2020,15(3):425-431
Electrochemical reduction of carbon dioxide (CO2) to CO is regarded as an efficient method to utilize the greenhouse gas CO2, because the CO product can be further converted into high value‐added chemicals via the Fisher–Tropsch process. Among all electrocatalysts used for CO2‐to‐CO reduction, Au‐based catalysts have been demonstrated to possess high selectivity, but their precious price limits their future large‐scale applications. Thus, simultaneously achieving high selectivity and reasonable price is of great importance for the development of Au‐based catalysts. Here, we report Ag@Au core–shell nanowires as electrocatalyst for CO2 reduction, in which a nanometer‐thick Au film is uniformly deposited on the core Ag nanowire. Importantly, the Ag@Au catalyst with a relative low Au content can drive CO generation with nearly 100 % Faraday efficiency in 0.1 m KCl electrolyte at an overpotential of ca. ?1.0 V. This high selectivity of CO2 reduction could be attributed to a suitable adsorption strength for the key intermediate on Au film together with the synergistic effects between the Au shell and Ag core and the strong interaction between CO2 and Cl? ions in the electrolyte, which may further pave the way for the development of high‐efficiency electrocatalysts for CO2 reduction. 相似文献
119.
Starch nanoparticle (SNP)‐based pressure sensitive adhesives (PSAs) with core‐shell particle morphology (starch nanoparticle core/acrylic polymer shell) are produced via seeded, semi‐batch emulsion polymerization at 15 wt% SNP loading (relative to total polymer weight) and 40 wt% latex solids. Crosslinker and chain transfer agent (CTA) are introduced to the acrylic shell polymer formulation at a range of concentrations according to a 32 factorial design to tailor the latex and adhesive properties of SNP‐based latexes. The crosslinker and CTA show no significant effect on polymerization kinetics, particle size, and viscosity. Latex gel content is predicted using an empirical model, which is a function of crosslinker and CTA concentration. Both the gel content and glass transition temperature strongly affect the adhesive properties (tack, peel strength, and shear strength) of the SNP‐based latex films. 3D response surfaces for the adhesive properties are constructed to facilitate the design of SNP‐based PSAs with desired properties. 相似文献
120.
Jooung-Hyun Jo Hyun-Cheol Ko Byeong-Woo Kim Hyun Park In-won Lee Ho-Hwan Chun 《Composite Interfaces》2016,23(8):797-805
AbstractMarine fouling can be a serious problem in the shipping industry, since it increases the surface roughness of the hull and hence its frictional resistance to its movement through water. Antifouling paint can be defined as preventing the attachment of marine organisms onto surfaces. However, the most commonly used antifouling coating which is the tributyltin-based self-polishing copolymer causes the severe pollution of marine environment. Ammonium salt-based paints include tertiary amines as biocides which have effective biocidal and biodegradable properties without accumulation in the sea environment. However, ammonium salt-based coatings were too sensitive to seawater and became swollen. In this study, polyurethane-acrylic copolymers were synthesized by radical polymerization. These hybrid materials were found to form core–shell structures in aqueous media. Synthesis and properties of copolymers were investigated by Fourier transform-infrared spectrometer, proton-nuclear magnetic resonance, transmission electron microscopy, and dynamic light scattering. The polishing rate of self-polishing copolymer was determined from the reduction in dry film thickness after artificial seawater immersion under a dynamic condition. 相似文献