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31.
Didjay F. Bruggeman Tijmen M. A. Bakker Dr. Simon Mathew Prof. Dr. Joost N. H. Reek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(1):218-221
This work reports a dye-sensitized photoelectrochemical cell (DSPEC) that couples redox-mediated light-driven oxidative organic transformations to reductive hydrogen (H2) formation. The DSPEC photoanode consists of a mesoporous anatase TiO2 film on FTO (fluorine-doped tin oxide), sensitized with the thienopyrroledione-based dye AP11 , while H2 was formed at a FTO-Pt cathode. Irradiation of the dye-sensitized photoanode transforms 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) to the oxidized TEMPO (TEMPO+), which acts as a chemical oxidant for the conversion of benzyl alcohol. The TEMPO0/+ couple, previously used as redox mediator in DSSC, mediates efficient electron transfer from the organic substrate to the photo-oxidized dye. A DSPEC photoreactor was designed that allows in situ monitoring the reaction progress by infrared spectroscopy and gas chromatography. Sustained light-driven oxidation of benzyl alcohol to benzaldehyde within the DSPEC photoreactor, using of TEMPO as mediator, demonstrated the efficiency of the device, with a photocurrent of 0.4 mA cm−2, approaching quantitative Faradaic efficiency and exhibiting excellent device stability. 相似文献
32.
Thermal activation of molecularly-wired gold nanoparticles on a substrate as catalyst 总被引:5,自引:0,他引:5
Luo J Jones VW Maye MM Han L Kariuki NN Zhong CJ 《Journal of the American Chemical Society》2002,124(47):13988-13989
The ability to prepare nanostructured metal catalysts requires the ability to control size and interparticle spatial and surface access properties. In this work, we report novel findings of an atomic force microscopic investigation of a controlled thermal activation strategy of gold catalysts nanostructured via molecular wiring or linking on a substrate surface. Gold nanocrystals of approximately 2 nm diameter capped by decanethiolate and wired by 1,9-nonanedithiolate on mica substrates were studied as a model system. By manipulating the activation temperature (200-250 degrees C), the capping/wiring molecules can be removed to produce controllable particle size and interparticle spatial morphology. The electrocatalytic activity of the activated nanostructures toward methanol oxidation, which is of fundamental importance to fuel cell catalysis, has been demonstrated. The novelty of the findings is the viability of a thermal activation strategy of core-shell nanostructured catalysts based on molecularly predefined interparticle spatial properties on a substrate, which upon further investigation may form the basis for spatially controllable nanostructured catalysts. 相似文献
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34.
A Novel Bismuth‐Based Metal–Organic Framework for High Volumetric Methane and Carbon Dioxide Adsorption 下载免费PDF全文
Mathew Savage Dr. Sihai Yang Dr. Mikhail Suyetin Prof. Dr. Elena Bichoutskaia Dr. William Lewis Prof. Dr. Alexander J. Blake Sarah A. Barnett Prof. Dr. Martin Schröder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(26):8024-8029
Solvothermal reaction of H4L (L=biphenyl‐3,3′,5,5′‐tetracarboxylate) and Bi(NO3)3 ? (H2O)5 in a mixture of DMF/MeCN/H2O in the presence of piperazine and nitric acid at 100 °C for 10 h affords the solvated metal–organic polymer [Bi2(L)1.5(H2O)2] ? (DMF)3.5 ? (H2O)3 (NOTT‐220‐solv). A single crystal X‐ray structure determination confirms that it crystallises in space group P2/c and has a neutral and non‐interpenetrated structure comprising binuclear {Bi2} centres bridged by tetracarboxylate ligands. NOTT‐220‐solv shows a 3,6‐connected network having a framework topology with a {4 ? 62}2{42 ? 65 ? 88}{62 ? 8} point symbol. The desolvated material NOTT‐220a shows exceptionally high adsorption uptakes for CH4 and CO2 on a volumetric basis at moderate pressures and temperatures with a CO2 uptake of 553 g L?1 (20 bar, 293 K) with a saturation uptake of 688 g L?1 (1 bar, 195 K). The corresponding CH4 uptake was measured as 165 V(STP)/V (20 bar, 293 K) and 189 V(STP/V) (35 bar, 293 K) with a maximum CH4 uptake for NOTT‐220a recorded at 20 bar and 195 K to be 287 V(STP)/V, while H2 uptake of NOTT‐220a at 20 bar, 77 K is 42 g L?1. These gas uptakes have been modelled by grand canonical Monte Carlo (GCMC) and density functional theory (DFT) calculations, which confirm the experimental data and give insights into the nature of the binding sites of CH4 and CO2 in this porous hybrid material. 相似文献
35.
Satheesh Chandran M Temina Mary Robert Sunitha K Dona Mathew C. P. Reghunadhan Nair 《先进技术聚合物》2014,25(8):881-890
This paper outlines the synthesis and characterization of O‐allyl aralkyl phenolic (O‐allyl Xylok, OAX) resins having low melt viscosity and its Alder‐ene blends with 2, 2′‐bis 4‐[(4′‐maleimido phenoxy) phenyl] propane. The blends manifested a three‐stage curing pattern that converged to a two‐stage pattern on enhancing the maleimide content. The polymerization kinetics of typical allyl and maleimide rich resin systems showed apparent activation energy increasing and pre‐exponential factor decreasing from ene to the Diels–Alder step. Increased allyl content improved mechanical and impact properties of the composites at ambient temperature, although it diminished the retention of interlaminar shear strength at elevated temperature. Increased maleimide content of the resin was conducive for the higher rigidity for the composite and its retention at elevated temperature. A substantial increase in Tg (from 153°C to 280°C) and thermal stability was observed with an increase in maleimide content. High allyl content resulted in improved mechanical properties thanks to better resin–reinforcement interaction as revealed from morphological analysis. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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37.
The cycloalkanones (1a-lf) have been converted into their corresponding cycloalkane carboxylates (2a-2f) by a lead (IV) acetate promoted rearrangement in presence of perchloric acid in triethyl orthoformate. 相似文献
38.
Spectral measures provide invariants for braided subfactors via fusion modules. In this paper we study joint spectral measures associated to the rank two Lie group G 2, including the McKay graphs for the irreducible representations of G 2 and its maximal torus, and fusion modules associated to all known G 2 modular invariants. 相似文献
39.
Beena Mathew P. M. Madhusudanan V. N. Rajasekharan Pillai 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1781-1800
Abstract Amino groups were incorporated into polyacrylamides with 2?20 mol% of crosslinking agents by transamidation with ethylenediamine. Divinylbenzene, N,Nv′-methylene-bis-acrylamide, and tetraethyleneglycol diacrylate were used as the crosslinking agents. The complexation of these resins, which contain ligand functions in different macromolecular structural environments, was investigated with Cu(II) ions. The Cu(II) uptake of these different resins was correlated with the molecular character and degree of crosslinking in the polymer matrix. The time course and kinetics of complexation depend on the nature of the crosslinking agent in the polymer matrix. The swelling behavior of the uncomplexed and complexed resins, structural characteristics, and thermal decomposition behavior were followed by IR, EPR, and thermal analysis. The swelling characteristics of the complexed resins are lower than those of the uncomplexed resins. Complexation resulted in shifting of the IR absorptions. The EPR parameters depend on the nature of crosslinking and are in agreement with the distorted tetragonal geometry of the Cu(II) complexes. The thermal decomposition behavior also depends on the nature and the degree of crosslinking in the polymer matrix. 相似文献
40.
This paper describes a simple method for the synthesis of water-soluble, silver nanoparticle-encapsulated β-cyclodextrin by phase transfer of silver nanoparticles from organic to aqueous phase using β-cyclodextrin as a capping agent. β-Cyclodextrin–silver nanoparticle inclusion complex was purified, characterised by spectroscopic and microscopic analyses and tested in vitro against Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens, Escherichia coli and Klebsiella pneumoniae. The silver nanoparticle-encapsulated β-cyclodextrin inclusion complex displayed considerable antimicrobial activity and stability. 相似文献