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941.
942.
Jialei Du Prof. Zuofeng Chen Dr. Shengrong Ye Prof. Benjamin J. Wiley Prof. Thomas J. Meyer 《Angewandte Chemie (International ed. in English)》2015,54(7):2073-2078
Copper metal is in theory a viable oxidative electrocatalyst based on surface oxidation to CuIII and/or CuIV, but its use in water oxidation has been impeded by anodic corrosion. The in situ formation of an efficient interfacial oxygen‐evolving Cu catalyst from CuII in concentrated carbonate solutions is presented. The catalyst necessitates use of dissolved CuII and accesses the higher oxidation states prior to decompostion to form an active surface film, which is limited by solution conditions. This observation and restriction led to the exploration of ways to use surface‐protected Cu metal as a robust electrocatalyst for water oxidation. Formation of a compact film of CuO on Cu surface prevents anodic corrosion and results in sustained catalytic water oxidation. The Cu/CuO surface stabilization was also applied to Cu nanowire films, which are transparent and flexible electrocatalysts for water oxidation and are an attractive alternative to ITO‐supported catalysts for photoelectrochemical applications. 相似文献
943.
Direct Insight into the Three‐Dimensional Internal Morphology of Solid–Liquid–Vapor Interfaces at Microscale 下载免费PDF全文
Dr. Shuai Yang Jiexing Du Dr. Moyuan Cao Dr. Xi Yao Dr. Jie Ju Dr. Xu Jin Prof. Bin Su Prof. Kesong Liu Prof. Lei Jiang 《Angewandte Chemie (International ed. in English)》2015,54(16):4792-4795
Solid–liquid–vapor interfaces dominated by the three‐phase contact line, usually performing as the active center in reactions, are important in biological and industrial processes. In this contribution, we provide direct three‐dimensional (3D) experimental evidence for the inside morphology of interfaces with either Cassie or Wenzel states at micron level using X‐ray micro‐computed tomography, which allows us to accurately “see inside” the morphological structures and quantitatively visualize their internal 3D fine structures and phases in intact samples. Furthermore, the in‐depth measurements revealed that the liquid randomly and partly located on the top of protrusions on the natural and artificial superhydrophobic surfaces in Cassie regime, resulting from thermodynamically optimal minimization of the surface energy. These new findings are useful for the optimization of classical wetting theories and models, which should promote the surface scientific and technological developments. 相似文献
944.
Direct Conversion of Bulk Metals to Size‐Tailored,Monodisperse Spherical Non‐Coinage‐Metal Nanocrystals 下载免费PDF全文
Rui‐Chun Luo Chao Li Prof. Xi‐Wen Du Prof. Jing Yang 《Angewandte Chemie (International ed. in English)》2015,54(16):4787-4791
Monodisperse non‐noble metal nanocrystals (NCs) that are highly uniform in shapes and particle size are much desired in various advanced applications, and are commonly prepared by either thermal decomposition or reduction, where reactive organometallic precursors or/and strong reducing agents are mandatory; however, these are usually toxic, costly, or suffer a lack of availability. Bulk Group 12 metals can now be converted into ligand‐protected, highly crystalline, monodisperse spherical metal NCs with precisely controlled sizes without using any precursors and reducers. The method is based on low‐power NIR‐laser‐induced size‐selective layer‐by‐layer surface vaporization. The monodisperse Cd NCs show pronounced deep‐UV (DUV) localized surface plasmon resonance making them highly competitive DUV‐plasmonic materials. This approach will promote appreciably the emergence of a wide range of monodisperse technically important non‐coinage metal NCs with compelling functionalities. 相似文献
945.
Teng‐Shuo Zhang Rui Du Yan‐Yin Zhao Jia‐Dan Xue Hui‐Gang Wang Xuming Zheng 《Journal of Raman spectroscopy : JRS》2016,47(3):299-309
The B‐band resonance Raman spectra of 2(1H)‐pyridinone (NHP) in water and acetonitrile were obtained, and their intensity patterns were found to be significantly different. To explore the underlying excited state tautomeric reaction mechanisms of NHP in water and acetonitrile, the vibrational analysis was carried out for NHP, 2(1D)‐pyridinone (NDP), NHP–(H2O)n (n = 1, 2) clusters, and NDP–(D2O)n (n = 1, 2) clusters on the basis of the FT‐Raman experiments, the B3LYP/6‐311++G(d,p) computations using PCM solvent model, and the normal mode analysis. Good agreements between experimental and theoretically predicted frequencies and intensities in different surrounding environments enabled reliable assignments of Raman bands in both the FT‐Raman and the resonance Raman spectra. The results indicated that most of the B‐band resonance Raman spectra in H2O was assignable to the fundamental, overtones, and combination bands of about ten vibration modes of ring‐type NHP–(H2O)2 cluster, while most of the B‐band resonance Raman spectra in CH3CN was assigned to the fundamental, overtones, and combination bands of about eight vibration modes of linear‐type NHP–CH3CN. The solvent effect of the excited state enol‐keto tautomeric reaction mechanisms was explored on the basis of the significant difference in the short‐time structural dynamics of NHP in H2O and CH3CN. The inter‐molecular and intra‐molecular ESPT reaction mechanisms were proposed respectively to explain the Franck–Condon region structural dynamics of NHP in H2O and CH3CN.Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
946.
947.
Fuyou Du Lin Sun Xian Zhen Honggang Nie Yanjie Zheng Guihua Ruan Jianping Li 《Analytical and bioanalytical chemistry》2015,407(20):6071-6079
High-internal-phase-emulsion polymers (polyHIPEs) show great promise as solid-phase-extraction (SPE) materials because of the tremendous porosity and highly interconnected framework afforded by the high-internal-phase-emulsion (HIPE) technique. In this work, polyHIPE monolithic columns as novel SPE materials were prepared and applied to trace enrichment of cytokinins (CKs) from complex plant samples. The polyHIPE monoliths were synthesized via the in-situ polymerization of the continuous phase of a HIPE containing styrene (STY) and divinylbenzene (DVB) in a stainless column, and revealed highly efficient and selective enrichment ability for aromatic compounds. Under the optimized experimental conditions, a method using a monolithic polyHIPE column combined with liquid chromatography–electrospray tandem mass spectrometry (LC–MS–MS) was developed for the simultaneous extraction and sensitive determination of trans-zeatin (tZ), meta-topolin (mT), kinetin (K), and kinetin riboside (KR). The proposed method had good linearity, with correlation coefficients (R 2) from 0.9957 to 0.9984, and low detection limits (LODs, S/N?=?3) in the range 2.4–47 pg mL?1 for the four CKs. The method was successfully applied to the determination of CKs in real plant samples, and obtained good recoveries ranging from 68.8 % to 103.0 % and relative standard deviations (RSDs) lower than 16 %. 相似文献
948.
949.
950.
Conjugated microporous polymers (CMPs) have recently received extensive attention in oil/organic solvent-water separation field as a kind of ideal porous absorbents with tunable porosity, large surface areas, and super-hydrophobicity. However, reports on the application of CMPs in adsorption of hydrophilic contaminants from water are very few. In this work, we studied the adsorption of metronidazole (MNZ), a polar antibiotic, by two kinds of CMPs. The adsorption characteristics of MNZ by the CMPs, including adsorption kinetics, mechanism, and isotherm parameters were calculated. The adsorption kinetics of MNZ was well expressed by the pseudo-second-order model, and the adsorption process was found to be mainly controlled by film diffusion. The adsorption isotherm data agreed well with the Langmuir isotherm model, and the values of free energy E indicated that the adsorption nature of MNZ on the CMPs was physisorption. Increasing dispersion degree of the CMPs in MNZ solution resulted in greater adsorption. This work may provide fundamental guidance for the removal of antibiotics by CMPs. 相似文献