排序方式: 共有87条查询结果,搜索用时 15 毫秒
61.
Mengying Le Bingjie Hu Meiying Wu Huazhang Guo Liang Wang 《Molecules (Basel, Switzerland)》2022,27(15)
For the sake of the oxygen reduction reaction (ORR) catalytic performance, carbon dots (CDs) doped with metal atoms have accelerated their local electron flow for the past few years. However, the influence of CDs doped with metal atoms on binding sites and formation mechanisms is still uncertain. Herein, Co,N-doped CDs were facilely prepared by the low-temperature polymerization–solvent extraction strategy from EDTA-Co. The influence of Co doping on the catalytic performance of Co-CDs was explored, mainly in the following aspects: first, the pyridinic N atom content of Co-CDs significantly increased from 4.2 to 11.27 at% compared with the CDs, which indicates that the Co element in the precursor is advantageous in forming more pyridinic-N-active sites for boosting the ORR performance. Second, Co-CDs are uniformly distributed on the surface of carbon black (CB) to form Co-CDs@CB by the facile hydrothermal route, which can expose more active sites than the aggregation status. Third, the highest graphite N content of Co-CDs@CB was found, by limiting the current density of the catalyst towards the ORR. Composite nanomaterials formed by Co and CB are also used as air electrodes to manufacture high-performance zinc–air batteries. The battery has good cycle stability and realizes stable charges and discharges under different current densities. The outstanding catalytic activity of Co-CDs@CB is attributed to the Co,N synergistic effect induced by Co doping, which pioneer a new metal doping mechanism for gaining high-performance electrocatalysts. 相似文献
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通过研究正硅酸乙酯(TEOS)水解的反应动力学,推导出Stber法制备二氧化硅溶胶体系中反应时间与TEOS转化率关系的动力学公式。分析确定了合适的转化率,进而用于计算二氧化硅溶胶的理论最佳反应时间。同时,以正硅酸乙酯为硅源,采用溶胶凝胶法在氨水催化作用下制备了不同配比的二氧化硅溶胶,考察了氨和水的浓度对反应时间的影响,结果表明,两者浓度增大可以有效减少反应时间。通过成膜性检测确定制备过程中的最佳反应时间,并与理论计算得到的最佳反应时间进行比较,结果表明,两者一致,误差控制在5%以内,说明该动力学公式具有很好的适用性。 2012-06-01;修订日期: 相似文献
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Mengying Chen Dongrui Yang Shifan Wu Dr. Jiabei Zhou Prof. Dali Zhou Dr. Can Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(38):9866-9875
One-dimensional materials exhibit fascinating properties in electrocatalytic applications but their fabrication faces the challenge of tedious and complicated operations. We have developed a bottom-up strategy to construct a 1D metal carbide catalyst (Mo2C@NC) consisting of ultrafine Mo2C nanoparticles embedded within nitrogen-doped carbon layers by simply calcining a mixture of ammonium molybdate, urea and melamine. Experimental results and thermodynamic calculations demonstrate that the retainable pyrolysis-generated self-supporting atmosphere plays a crucial role in the crystalline phase and morphology of materials. When functioned as an electrocatalyst for the hydrogen evolution reaction (HER), the achieved Mo2C@NC presents an excellent catalytic activity as well as outstanding stability. This work could shed fresh light onto the facile synthesis of effective HER catalysts with 1D nanostructure. 相似文献
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Liu Liang Wang Mengying Liu Chaobing Yang Zhaojun Chen Xin 《Journal of nanoparticle research》2022,24(9):1-20
Journal of Nanoparticle Research - The management of diabetes, in contrast to the treatment of the disease, is basically aimed at controlling the blood glucose level. Besides the primary changes... 相似文献
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We report the successful realization of a microfluidic chip with switching and corresponding inverting functionalities. The chips are identical logic control components incorporating a type of smart colloid, giant electrorheological fluid (GERF), which possesses reversible characteristics via a liquid-solid phase transition under external electric field. Two pairs of electrodes embedded on the sides of two microfluidic channels serve as signal input and output, respectively. One, located in the GERF micro-channel is used to control the flow status of GERF, while another one in the ither micro-fluidic channel is used to detect the signal generated with a passing-by droplet (defined as a signal droplet). Switching of the GERF from the suspended state (off-state) to the flowing state (on-state) or vice versa in the micro-channel is controlled by the appearance of signal droplets whenever they pass through the detection electrode. The output on-off signals can be easily demonstrated, clearly matching with GERF flow status. Our results show that such a logic switch is also a logic IF gate, while its inverter functions as a NOT gate. 相似文献
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Liqin Yang Zhiju Zhao Jie Hu Huibin Wang Junfang Dong Xiang Wan Zhenyu Cai Mengying Li 《Electroanalysis》2020,32(7):1651-1658
In this work, g‐C3N4, CuO and g‐C3N4/CuO?X (where × can be 3, 6, or 9) were synthesized through hydrothermal and calcination methods and used to fabricate photoelectrochemical (PEC) aptasensor for detection of bisphenol A (BPA). CuO nanoparticles covered with g‐C3N4 were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The aptasensor based on g‐C3N4/CuO‐6 possessed high PEC activity due to its good conductivity and low electron recombination rate. PEC experiments demonstrate that the aptasensor based on g‐C3N4/CuO‐6 exhibits a broad linear range towards BPA from 0.02–10 ng L?1 and 50–1200 ng L?1 and reveals superior stability, selectivity and repeatability. Thus, g‐C3N4/CuO‐6 composite is a promising material for the determination of BPA in PEC field and has commercially viable. 相似文献
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Xiaojie Xu Xufeng Zhou Tianyu Wang Xiang Shi Ya Liu Yong Zuo Limin Xu Mengying Wang Xiaofeng Hu Xinju Yang Jiaxin Chen Xiubo Yang Lin Chen Peining Chen Huisheng Peng 《Angewandte Chemie (International ed. in English)》2020,59(31):12762-12768
Electronic textiles may revolutionize many fields, such as communication, health care and artificial intelligence. To date, unfortunately, computing with them is not yet possible. Memristors are compatible with the interwoven structure and manufacturing process in textiles because of its two‐terminal crossbar configuration. However, it remains a challenge to realize textile memristors owing to the difficulties in designing advanced memristive materials and achieving high‐quality active layers on fiber electrodes. Herein we report a robust textile memristor based on an electrophoretic‐deposited active layer of deoxyribonucleic acid (DNA) on fiber electrodes. The unique architecture and orientation of DNA molecules with the incorporation of Ag nanoparticles offer the best‐in‐class performances, e.g., both ultra‐low operation voltage of 0.3 V and power consumption of 100 pW and high switching speed of 20 ns. Fundamental logic calculations such as implication and NAND are demonstrated as functions of textile chips, and it has been thus integrated with power‐supplying and light emitting modules to demonstrate an all‐fabric information processing system. 相似文献
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Science China Mathematics - We propose a dynamically integrated regression model to predict the price of online auctions, including the final price. Different from existing models, the proposed... 相似文献