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Research on Chemical Intermediates - Several attempts have been made to obtain aliphatic dicarboxylic diesters from esterification reaction to develop the biomass-derived platform molecules and... 相似文献
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双金属有机骨架及其衍生物一方面具有单金属有机骨架孔道丰富、比表面积大、结构可调、活性位点丰富等特点,另一方面具有双组分与多孔结构之间的协同效应,因而受到了研究人员的密切关注,在储能、催化、分离、传感器、医药、气体存储等领域广泛应用。和单金属MOFs类似,双金属MOFs的导电性不佳、结构易坍塌,这极大地限制了其在电化学储能中的应用。通过对双金属MOFs进行热处理,易得到分布均匀的多孔碳@双金属氧化物/硫化物/磷化物/硒化物等衍生物,不仅保持了独特的多孔结构,而且提高了材料的导电性和结构稳定性,有利于在电化学储能中的应用。因此,本文从双金属MOFs中的主要金属离子入手,综述了双金属MOFs及其衍生物用于超级电容器、锂离子电池、钠离子电池、金属空气电池等电化学储能器件的最新应用进展。在此基础上,总结了双金属MOFs在电化学储能应用中的优势,并对其制备、作用机理和后处理研究提出了建议。 相似文献
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Qun He Daobin Liu Ji Hoon Lee Yumeng Liu Zhenhua Xie Sooyeon Hwang Shyam Kattel Li Song Jingguang G. Chen 《Angewandte Chemie (International ed. in English)》2020,59(8):3033-3037
The electrochemical CO2 reduction reaction (CO2RR) to yield synthesis gas (syngas, CO and H2) has been considered as a promising method to realize the net reduction in CO2 emission. However, it is challenging to balance the CO2RR activity and the CO/H2 ratio. To address this issue, nitrogen‐doped carbon supported single‐atom catalysts are designed as electrocatalysts to produce syngas from CO2RR. While Co and Ni single‐atom catalysts are selective in producing H2 and CO, respectively, electrocatalysts containing both Co and Ni show a high syngas evolution (total current >74 mA cm?2) with CO/H2 ratios (0.23–2.26) that are suitable for typical downstream thermochemical reactions. Density functional theory calculations provide insights into the key intermediates on Co and Ni single‐atom configurations for the H2 and CO evolution. The results present a useful case on how non‐precious transition metal species can maintain high CO2RR activity with tunable CO/H2 ratios. 相似文献
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Yumeng Xi Trevor W. Butcher Jing Zhang John F. Hartwig 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(2):786-790
We report the regioselective and enantioselective formal hydroamination of unsymmetrical internal alkenes catalyzed by a copper catalyst ligated by DTBM‐SEGPHOS. The regioselectivity of the reaction is controlled by the electronic effects of ether, ester, and sulfonamide groups in the homoallylic position. The observed selectivity underscores the influence of inductive effects of remote substituents on the selectivity of catalytic processes occurring at hydrocarbyl groups, and the method provides direct access to various 1,3‐aminoalcohol derivatives with high enantioselectivity. 相似文献
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Ke D Wang X Yang Q Niu Y Chai S Chen Z An X Shen W 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14112-14117
The interaction between dodecyltrimethylammonium bromide (DTAB) and curcumin has been studied in pH 5.0 sodium phosphate buffer using absorption and fluorescence measurements. With increasing DTAB concentration (C(DTAB)) from 0 to 20 mM, the absorption peak of curcumin at 430 nm, corresponding to the conjugated structure of curcumin, first weakens gradually into a shoulder but increases back into one peak with much higher absorption intensity. On the contrary, as C(DTAB) increases, the initial small absorption shoulder of curcumin at 355 nm, corresponding to the feruloyl unit of curcumin, first increases gradually into a clear peak but decreases back into one shoulder until almost disappeared finally. By remaining at nearly the same wavelength, the fluorescence of curcumin first decreases at C(DTAB) lower than 5 mM and then increases gradually up to C(DTAB) = 10 mM, which is followed by sharp increases of fluorescence intensity with marked blue-shifts at higher C(DTAB). The values of anisotropy and microviscosity of curcumin obtained from the fluorescence polarization technique also showed pronounced changes at different surfactant concentrations. The interaction mechanisms of DTAB with curcumin have been presented at low, intermediate, and high surfactant concentrations, which is relating to interaction forces, surfactant aggregations, as well as structural alterations of curcumin. 相似文献
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Ying Han Yumeng Fei Mingxin Wang Yingang Xue Hui Chen Yuxuan Liu 《Molecules (Basel, Switzerland)》2021,26(14)
Bisphenol Z (BPZ), bisphenol S (BPS), bisphenol C (BPC), and bisphenol F (BPF) had been widely used as alternatives to bisphenol A (BPA), but the toxicity data of these bisphenol analogues were very limited. In this study, the joint toxicity of BPZ, BPS, BPC, and BPF to zebrafish (Danio rerio) was investigated. The median half lethal concentrations (LC50) of BPZ, BPS, BPC, and BPF to zebrafish for 96 h were 6.9 × 105 µM, 3.9 × 107 µM, 7.1 × 105 µM, and1.6 × 106 µM, respectively. The joint toxicity effect of BPF–BPC (7.7 × 105–3.4 × 105µM) and BPZ–BPC (3.4 × 105–3.5 × 105µM) with the same toxic ratio showed a synergistic effect, which may be attributed to enzyme inhibition or induction theory. While the toxicity effect of the other two bisphenol analogue combined groups and multi-joint pairs showed an antagonistic effect due to the competition site, other causes need to be further explored. Meanwhile, the expression levels of the estrogen receptor genes (ERα, ERβ1) and antioxidant enzyme genes (SOD, CAT, GPX) were analyzed using a quantitative real-time polymerase chain reaction in zebrafish exposure to LC50 of BPZ, BPS, BPC, and BPF collected at 24, 48, 72, and 96 h. Relative expression of CAT, GPX, and ERβ1 mRNA declined significantly compared to the blank control, which might be a major cause of oxidant injury of antioxidant systems and the disruption of the endocrine systems in zebrafish. 相似文献
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A novel ZnCo2O4/Bi2O3 heterojunction photocatalyst was prepared via balling method. The enhanced photocatalytic activity is mainly attributed to the broad photoabsorption and low recombination rate of photogenerated electron-hole pairs, which is driven by the photogenerated potential difference formed at the ZnCo2O4/Bi2O3 heterojunction interface. 相似文献