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991.
Hang Zhao Ping Zhang Yudong Wang Weiping Huang Shoumin Zhang 《Journal of Sol-Gel Science and Technology》2014,71(3):406-412
A new preparation method for Au/TiO2 nanotubes (NTs) by combing sol–gel with hydrothermal treatment technique was developed. The TiO2 NTs calcined at 300 °C were nearly uniform, and the gold particles were distributed homogeneously. The possible formation mechanism was suggested. The 5 % Au/TiO2 NTs calcined at 300 °C had the best catalytic activity for CO oxidation, and their conversion of CO remained at 100 % during 60 h on stream. This preparation method could improve the thermal stability of Au/TiO2 nanotube catalysts. 相似文献
992.
目的运用火焰原子吸收光谱法测定中药草珊瑚叶中的Fe、Zn、Mg、Ca、Cu 5种金属元素的含量。方法用浓HNO3-HCl O4消解样品,采用标准曲线法测定其5种金属元素含量。结果所测的样品中含有丰富的人体必需微量元素。方法回收率在99.35%-103.30%之间,样品相对偏差小于5%。结论该法简单、准确,结果令人满意。 相似文献
993.
Huijun Yang Zhi Chang Dr. Yu Qiao Han Deng Xiaowei Mu Prof. Ping He Prof. Haoshen Zhou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9463-9467
Rechargeable aqueous zinc batteries (RAZB) have been re-evaluated because of the superiority in addressing safety and cost concerns. Nonetheless, the limited lifespan arising from dendritic electrodeposition of metallic Zn hinders their further development. Herein, a metal–organic framework (MOF) was constructed as front surface layer to maintain a super-saturated electrolyte layer on the Zn anode. Raman spectroscopy indicated that the highly coordinated ion complexes migrating through the MOF channels were different from the solvation structure in bulk electrolyte. Benefiting from the unique super-saturated front surface, symmetric Zn cells survived up to 3000 hours at 0.5 mA cm−2, near 55-times that of bare Zn anodes. Moreover, aqueous MnO2–Zn batteries delivered a reversible capacity of 180.3 mAh g−1 and maintained a high capacity retention of 88.9 % after 600 cycles with MnO2 mass loading up to 4.2 mg cm−2. 相似文献
994.
Dr. Weihui Ou Dr. Binbin Zhou Junda Shen Dr. Tsz Wing Lo Prof. Dangyuan Lei Dr. Shengliang Li Jing Zhong Prof. Yang Yang Li Prof. Jian Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(17):6856-6859
Hot carriers (HCs) and thermal effects, stemming from plasmon decays, are crucial for most plasmonic applications. However, quantifying these two effects remains extremely challenging due to the experimental difficulty in accurately measuring the temperature at reaction sites. Herein, we provide a novel strategy to disentangle HCs from photothermal effects based on the different traits of heat dissipation (long range) and HCs transport (short range), and quantitatively uncover the dominant and potential-dependent role of photothermal effect by investigating the rapid- and slow-response currents in plasmon-mediated electrochemistry at nanostructured Ag electrode. Furthermore, the plasmoelectric surface potential is found to contribute to the rapid-response currents, which is absent in the previous studies. 相似文献
995.
Jian Fang Evan M. Howard Prof. Dr. Matthias Brewer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):12927-12931
Structurally complex diazo-containing scaffolds are formed by conjugate addition to vinyl diazonium salts. The electrophile, a little studied α-diazonium-α,β-unsaturated carbonyl compound, is formed at low temperature under mild conditions by treating β-hydroxy-α-diazo carbonyls with Sc(OTf)3. Conjugate addition occurs selectively at the 3-position of indole to give α-diazo-β-indole carbonyls, and enoxy silanes react to give 2-diazo-1,4-dicarbonyl products. These reactions result in the formation of tertiary and quaternary centers, and give products that would be otherwise difficult to form. Importantly, the diazo functional group is retained within the molecule for future manipulation. Treating an α-diazo ester indole addition product with Rh2(OAc)4 caused a rearrangement to occur to give a 2-(1H-indol-3-yl)-2-enoate. In the case of diazo ketone compounds, this shift occurred spontaneously on prolonged exposure to the Lewis acidic reaction conditions. 相似文献
996.
Luocai Yi Dr. Junxiang Chen Ping Shao Dr. Junheng Huang Xinxin Peng Junwei Li Dr. Genxiang Wang Chi Zhang Prof. Zhenhai Wen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20287-20294
Two-dimensional (2D) monometallic pnictogens (antimony or Sb, and bismuth or Bi) nanosheets demonstrate potential in a variety of fields, including quantum devices, catalysis, biomedicine and energy, because of their unique physical, chemical, electronic and optical properties. However, the development of general and high-efficiency preparative routes toward high-quality pnictogen nanosheets is challenging. A general method involving a molten-salt-assisted aluminothermic reduction process is reported for the synthesis of Sb and Bi nanosheets in high yields (>90 %). Electrocatalytic CO2 reduction was investigated on the Bi nanosheets, and high catalytic selectively to formate was demonstrated with a considerable current density at a low overpotential and an impressive stability. Bi nanosheets continuously convert CO2 into formate in a flow cell operating for one month, with a yield rate of 787.5 mmol cm−2 h−1. Theoretical results suggest that the edge sites of Bi are far more active than the terrace sites. 相似文献
997.
Yi-Fan Wang Yiyu Liang Yan-Fang Wu Jian Yang Xu Zhang Dr. Dandan Cai Dr. Xu Peng Dr. Mohamedally Kurmoo Prof. Dr. Ming-Hua Zeng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13334-13339
The in situ tracking of the pyrolysis of a binary molecular cluster [Zn7(μ3-CH3O)6(L)6][ZnLCl2]2 is presented with one brucite disk and two mononuclear fragments (L=mmimp: 2-methoxy-6-((methylimino)-methyl)phenolate) to porous carbon using TG-MS from 30 to 900 °C. Following up the spilled gas product during the decomposed reaction of zinc cluster along the temperature rising, and in conjunction with XRD, SEM, BET and other materials characterization, where three key steps were observed: 1) cleavage of the bulky external ligand; 2) reduction of ZnO and 3) volatilization of Zn. The real-time-dependent phase-sequential evolution of the remaining products and the processing of pore forming template transformation are proposed simultaneously. The porous carbon structure featuring a uniform nano-sized pore distribution synthesized at 900 °C with the highest surface area of 1644 m2 g−1 and pore volume of 0.926 cm3 g−1 exhibits the best known capacitance of 662 F g−1 at 0.5 A g−1. 相似文献
998.
Yanan Jiang Wenjie Ma Yujuan Qiao Yifei Xue Jiahao Lu Jun Gao Nannan Liu Fei Wu Prof. Ping Yu Prof. Lei Jiang Prof. Lanqun Mao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):12895-12899
Biological ion channels and ion pumps with sub-nanometer sizes modulate ion transport in response to external stimuli. Realizing such functions with sub-nanometer solid-state nanopores has been an important topic with wide practical applications. Herein, we demonstrate a biomimetic photoresponsive ion channel and photodriven ion pump using a porphyrin-based metal–organic framework membrane with pore sizes comparable to hydrated ions. We show that the molecular-size pores enable precise and robust optoelectronic ion transport modulation in a broad range of concentrations, unparalleled with conventional solid-state nanopores. Upon decoration with platinum nanoparticles to form a Schottky barrier photodiode, photovoltage across the membrane is generated with “uphill” ion transport from low concentration to high concentration. These results may spark applications in energy conversion, ion sieving, and artificial photosynthesis. 相似文献
999.
Dr. Ke Li Dr. Jian Yang Prof. Rong Huang Prof. Shaoliang Lin Prof. Jinlou Gu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(33):14228-14232
Ordered mesoporous metal–organic frameworks (mesoMOFs) were constructed with a uniform pore size up to about 10 nm and thick microporous walls, opening up the possibility for the mass diffusion of large-size molecules through crystalline MOFs. The synergistic effects based on triblock copolymer templates and the Hofmeister salting-in anions promote the nucleation of stable MOFs in aqueous phase and the in situ crystallization of MOFs around templates, rendering the generation of a microcrystal with periodically arranged large mesopores. The improved mass transfer benefiting from large-pore channels, together with robust microporous crystalline structure, endows them as an ideal nanoreactor for the highly efficient digestion of various biogenic proteins. This strategy could set a guideline for the rational design of new ordered large-pore mesoMOFs with a variety of compositions and functionalities and pave a way for their potential applications with biomacromolecules. 相似文献
1000.
Prof. Ping Yu Huan Wei Peipei Zhong Yifei Xue Dr. Fei Wu Dr. Yang Liu Prof. Junjie Fei Prof. Lanqun Mao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22841-22847
The development of new principles and techniques with high neuronal compatibility for quantitatively monitoring the dynamics of neurochemicals is essential for deciphering brain chemistry and function but remains a great challenge. We herein report a neuron-compatible method for in vivo neurochemical sensing by powering a single carbon fiber through spontaneous bipolar electrochemistry as a new sensing platform. By using ascorbic acid as a model target to prove the concept, we found that the single-carbon-fiber-powered microsensor exhibited a good response, high stability and, more importantly, excellent neuronal compatibility. The microsensor was also highly compatible with electrophysiological recording, thus enabling the synchronous recording of both chemical and electrical signals. The sensing principle could be developed for in vivo monitoring of various neurochemicals in the future by rationally designing and tuning the electrochemical reactions at the two poles of the carbon fiber. 相似文献