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191.
A novel gold‐catalyzed tandem protocol, initiated by hydride transfer in the presence of catalytic (C6F5)3PAuCl/AgSbF6, for the formation of fused polycyclic ring systems has been achieved. This tandem reaction provides rapid access to various fused polycyclic species in a single chemical operation, leading to stereospecific formation of two carbon–carbon bonds and three rings.  相似文献   
192.
提出了液相剪切剥离蒙脱土(MMT)制备寡层纳米片(MNSs)并将其原位引入PLA基体的方法, 可经简单的刮刀涂覆法(Blade coating)制备MNSs质量分数为2%, 5%和10%的PLA基纳米复合薄膜. 该技术路线赋予了MNSs在PLA基体中充分剥离(片层间距可达3.11 nm)和良好取向排列以及较强的界面相互作用. 这些结构特征使得纳米复合薄膜的结晶度和力学性能得到大幅提升, 同时显著降低了氧气渗透系数. 本文不仅提出了可规模化原位剥离二维纳米片的有效方法, 更为制备高强高阻隔全降解复合材料及其结构-性能关系研究提供了思路.  相似文献   
193.
Currently, the excessive consumption of fossil fuels is accompanied by massive emissions of CO2, leading to severe energy shortages and intensified global warming. It is of great significance to develop and use renewable clean energy while reducing the concentration of CO2 in the atmosphere. Photocatalytic technology is a promising strategy for carbon dioxide conversion. Clearly, the achievement of the above goals largely depends on the design and construction of catalysts. This review is mainly focused on the application of 2D materials for photocatalytic CO2 reduction. The contribution of synthetic strategies to their structure and performance is emphasized. Finally, the current challenges, and prospects of 2D materials for photoreduction of CO2 with high efficiency, even for practical applications are discussed. It is hoped that this review can provide some guidance for the rational design, controllable synthesis of 2D materials, and their application for efficient photocatalytic CO2 reduction.  相似文献   
194.
理解析氧反应(OER)电催化剂活性位点的活性来源是开发高效电催化剂的关键。然而,由于催化剂结构-活性关系的复杂性,发展高效电催化剂仍然是一个至关重要的挑战。本文设计了不同Co-N-C催化剂构型,包括单原子、双原子和团簇,并通过第一性原理计算建立了析氧反应构效关系。结果表明,Co-N4由于金属中心的高配位数和与所有析氧反应中间体的适中吸附能,表现出最佳反应性,过电位为0.37V。双原子和团簇的活性来源于催化剂自身与反应中间体相结合的高度配位结构。此外,本文基于Co-N4构型讨论了影响OER活性的其他因素,其中弱金属-金属相互作用可以通过调节Co-O的反键能级优化含氧中间体的吸附降低反应过电位。随后,根据建立的结构-吸附-活性关系,对火山图进行外推,得到CoNi-type4体系OER的过电位为0.23V。本文研究揭示了Co-N-C催化剂OER活性的起源,建立了基于原子尺度的Co-N-C催化剂的构效关系,有助于理解M-N-C基催化剂的高性能,并促进高效OER催化剂的设计。  相似文献   
195.
Li  Ji  Cui  Xiancai  Lin  Qilang  Lyu  Xiaolin  Wang  Qian  Yu  Yan  Yang  Chengkai 《Journal of Solid State Electrochemistry》2023,27(6):1383-1389
Journal of Solid State Electrochemistry - As people possess more safety conscious, the issue of electrolytes is attracting concern. The gel polymer electrolyte offers high ionic conductivity,...  相似文献   
196.
Mesoscopic perovskite solar cells using stable CH3NH3PbI2Br as a light absorber and low‐cost poly(3‐hexylthiophene) (P3HT) as hole‐transporting layer were fabricated, and a power conversion efficiency of 6.64 % was achieved. The partial substitution of iodine with bromine in the perovskite led to remarkably prolonged charge carrier lifetime. Meanwhile, the replacement of conventional thick spiro‐MeOTAD layer with a thin P3HT layer has significantly reduced the fabrication cost. The solar cells retained their photovoltaic performance well when they were exposed to air without any encapsulation, presenting a favorable stability. The combination of CH3NH3PbI2Br and P3HT may render a practical and cost‐effective solid‐state photovoltaic system. The superior stability of CH3NH3PbI2Br is also promising for other photoconversion applications.  相似文献   
197.
Conventional electronic circuits can perform multi‐level logic operations; however, this capability is rarely realized by biological logic gates. In addition, the question of how to close the gap between biomolecular computation and silicon‐based electrical circuitry is still a key issue in the bioelectronics field. Here we explore a novel split aptamer‐based multi‐level logic gate built from INHIBIT and AND gates that performs a net XOR analysis, with electrochemical signal as output. Based on the aptamer–target interaction and a novel concept of electrochemical rectification, a relayed charge transfer occurs upon target binding between aptamer‐linked redox probes and solution‐phase probes, which amplifies the sensor signal and facilitates a straightforward and reliable diagnosis. This work reveals a new route for the design of bioelectronic logic circuits that can realize multi‐level logic operation, which has the potential to simplify an otherwise complex diagnosis to a “yes” or “no” decision.  相似文献   
198.
In this study, the characterization and photocatalytic activity of TiO2 nanotube arrays prepared by anodization process with starch addition were investigated in detail. The results suggested that the optimum mass fraction of starch added in anodization process was 0.1%, with which TiO2 nanotube arrays owning good tubular structure were synthesized. The tube length and average inner diameter of nanotubes were approximately 4 μm and 30 nm, respectively. Through the characterization of TiO2 nanotube arrays by energy dispersive spectrometer, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier Transform Infrared (FTIR) spectroscopy, it was found that the as‐prepared nanotubes possessed well uniformed and higher photodegradation responsive than the pure TiO2. Moreover, it was expected that the as‐prepared nanotubes exhibited good photocatalytic activity for the degradation of RhB under UV‐light irradiation, which could be ascribed to their good morphology, enhanced UV‐light absorption property and electron transmission ability during the photocatalytic reaction. In addition, the nanotubes were not significantly regenerated during the cycling runs experiment. Overall, this study could provide a principle method to synthesize TiO2 nanotube arrays with enhanced photocatalytic activity by anodization process with starch addition for environmental purification.  相似文献   
199.
以具有高比表面积、分级孔结构和优良导电性的碳纳米笼(CNCs)为载体,制得了粒子尺寸为10~25 nm且高度分散的LiFePO4/CNCs复合物.以LiFePO4/CNCs复合物作为锂离子电池的正极材料,在0.1 C倍率下首次放电比容量达到163 mAh·g-1,15 C和30 C倍率下的放电比容量可达96和75 mAh·g-1;在15 C倍率下循环200圈后,其放电比容量仍保持在92 mAh·g-1,显著优于LiFePO4/CNTs复合物.这些结果表明,LiFePO4/CNCs复合物具有优异的倍率性能和循环稳定性,是一种性能优良的锂离子电池正极材料,其性能源自CNCs载体的高比表面积、分级孔结构和优异导电性以及LiFePO4颗粒的纳米化和高结晶度.  相似文献   
200.
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