Faraday Discussions of The Chemical Society最新文献_第9页

Ion transport in polymer electrolytes 聚合物电解质中的离子传输

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898800055

G. G. Cameron, M. Ingram, J. Harvie

引用次数: 28

Charge transfer in conducting polymers. Striving toward intrinsic properties 导电聚合物中的电荷转移。追求内在属性

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898800203

A. Heeger

{"title":"Charge transfer in conducting polymers. Striving toward intrinsic properties","authors":"A. Heeger","doi":"10.1039/DC9898800203","DOIUrl":"https://doi.org/10.1039/DC9898800203","url":null,"abstract":"A principal goal of the field of conducting polymers is to strive for advances in materials quality that will enable the exploration of the intrinsic electrical properties. In this context, we summarize the requirements for achieving high performance conducting polymers with electrical conductivities greater than that of copper. To avoid localization onto one-dimensioal polymer chains (with bandwidth 4t0), interchain charge transfer (t3d) is required. For crystalline materials in which the chains have precise phase order, the mean distance along the chain between defects must be L/acrystalline≫t0/t3d. In the case where there is good chain extension and good chain alignment, but when that alignment is nematic (i.e. with random interchain phase along the chain), the criterion is more severe: L/anematic≫(t0/t3d)2. When the appropriate inequality is satisfied the transport is that of an anisotropic three-dimensional metal, and the conductivity will increase in proportion to the mean distance between chain interruptions, cross-links, sp3 defects etc. If the mean defect scattering time, τdef=(L/vF), becomes sufficiently long that phonon scattering limits the mean free path, then the conductivity takes on a metallic temperature dependence, and the system is in the clean and intrinsic transport limit.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"17 1","pages":"203-211"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88648010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 57

Acid–base and oxidation catalysis on heteropolysalts with surface acid layers 表面有酸层的杂多盐的酸碱和氧化催化

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898700173

K. Bruckman, J. Haber, E. Serwicka

引用次数: 36

Ion transport in pyrrole-based polymer films 吡咯基聚合物薄膜中的离子输运

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898800165

Huanyu Mao, J. Ochmańska, C. Paulse, P. Pickup

{"title":"Ion transport in pyrrole-based polymer films","authors":"Huanyu Mao, J. Ochmańska, C. Paulse, P. Pickup","doi":"10.1039/DC9898800165","DOIUrl":"https://doi.org/10.1039/DC9898800165","url":null,"abstract":"Ionic resistivities and counterion diffusion coefficients for polypyrrole, poly-[1-methyl-3-(pyrrol-1-ylmethyl)pyridinium](poly-MPMP+) and pyrrolex-[Ru(2,2′-bipyridine)2(3-(pyrrol-1-ylmethyl) pyridine)Cl]+ copolymer films have been obtained by chronoamperometry using the single-pore model. For poly-MPMP+ both the electronic resistivity and the ionic resistivity can be simultaneously determined. Finite-difference simulations have been used to confirm the validity of the equations used and to extend the applicability of the model.Counterion diffusion coefficients in polypyrrole and poly-MPMP+ have also been determined by rotating-disc voltammetry and d.c. conductivity measurements. Where possible the results have been confirmed by the use of two independent methods. Diffusion coefficients for I–, Cl–, ClO4– and Fe(CN)64– in the above polymers in water and/or acetonitrile are compared and discussed. It is concluded that: (a) polypyrrole and poly-MPMP+ are solvated and swollen to a much greater extent in water than in acetonitrile, (b) permanent cationic sites increase the permeability of polypyrrole in water but not in acetonitrile and (c) the permeability of polypyrrole in acetonitrile can be increased by the incorporation of bulky metal complexes.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"48 1","pages":"165-176"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85077259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 36

Transport and kinetics in multicomponent chemically modified electrodes 多组分化学修饰电极的输运和动力学

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898800139

M. Lyons, D. McCormack, Orla Smyth, P. Bartlett

引用次数: 18

Copper–zinc oxide catalysts. Activity in relation to precursor structure and morphology 铜氧化锌催化剂。与前体结构和形态有关的活性

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898700107

D. Waller, D. Stirling, F. Stone, M. S. Spencer

引用次数: 109

Nature of active species of (VO)2P2O7 for selective oxidation of n-butane to maleic anhydride (VO)2P2O7选择性氧化正丁烷制马来酸酐的活性物质性质

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898700215

G. Centi, F. Trifiró, G. Busca, J. Ebner, J. Gleaves

引用次数: 60

Mechanistic relationships in the activation of methane and the conversion of methanol on heteropoly oxometallates 甲烷活化与甲醇在异多金属氧酸盐上转化的机理关系

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898700023

Shamsuddin Ahmed, S. Kasztelan, J. Moffat

{"title":"Mechanistic relationships in the activation of methane and the conversion of methanol on heteropoly oxometallates","authors":"Shamsuddin Ahmed, S. Kasztelan, J. Moffat","doi":"10.1039/DC9898700023","DOIUrl":"https://doi.org/10.1039/DC9898700023","url":null,"abstract":"Heteropoly oxometallates have been employed in the heterogeneous catalysis of the conversion of methanol to hydrocarbons and the partial oxidation of methane. In the former process methanol is first protonated at Bronsted-acid sites, but at higher temperatures the heteropoly anions are partially methylated subsequent to scission of the C—O bonds in protonated methanol. With silica-supported 12-molybdophosphoric acid the exchange of the protons by cations effectively poisons the catalyst for the conversion of methane. Introduction of a chloro-additive to the feedstream in the latter process produces changes in the conversion and selectivity which are markedly different for the molybdenum- and tungsten-containing catalysts. With the former the conversion of methane is increased while the selectivity to partial oxidation products is decreased. With the latter the former comments are also applicable but selectivities to methyl chloride reach as high as 90 mol %. The results from cation exchange and the addition of a chloro-additive are interpreted and a mechanism with common features is proposed for the methanol and methane conversion processes.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"166 1","pages":"23-32"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77291950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Carbon monoxide hydrogenation selectivity of catalysts derived from ruthenium clusters on acidic pillared clay and basic layered double-hydroxide supports 酸性柱状粘土和碱性层状双氢氧化物载体上钌团簇催化剂的一氧化碳加氢选择性

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898700227

T. Pinnavaia, M. Rameswaran, E. Dimotakis, E. Giannelis, E. Rightor

{"title":"Carbon monoxide hydrogenation selectivity of catalysts derived from ruthenium clusters on acidic pillared clay and basic layered double-hydroxide supports","authors":"T. Pinnavaia, M. Rameswaran, E. Dimotakis, E. Giannelis, E. Rightor","doi":"10.1039/DC9898700227","DOIUrl":"https://doi.org/10.1039/DC9898700227","url":null,"abstract":"Acidic pillared clays, e.g. alumina pillared montmorillonite (APM), and basic layered double hydroxides, e.g. hydrotalcite (HT), provide well defined surface environments for dispersing metal-cluster carbonyl complexes. In the present work, FTIR spectroscopic studies have been used to elucidate the surface organometallic chemistry of Ru3(CO)12 on APM and HT. For APM as the support, cluster binding occurs initially by protonation to form H Ru3(CO)12+ cations on the intracrystalline gallery surfaces of the clay. Further reaction results in the grafting of mononuclear sites of the type [Ru(CO)x(OAl)2]n(x= 2, 3) to the pillar surfaces. The reaction of Ru3(CO)12 with HT affords chemisorbed H Ru3(CO)11– anions which can be tranformed to surface-bound [Ru(CO)x(OM)2]n(M = Al, Mg) complexes analogous to the grafted species on APM. The reduction of the grafted complex on both supports results in active ruthenium catalysts for CO hydrogenation. Ru-APM exhibits very high selectivity for isomerized hydrocarbons (branched alkanes and internal alkenes). The isomerized products arise from the unique texture and bifunctional nature of Ru-APM; the clay-embedded ruthenium catalyses Fischer–Tropsch chain propagation, and the intracrystalline Bronsted acidity of the clay host catalyses alkene rearrangements through carbenium-ion mechanisms. In contrast, the Ru-HT system gives very different product distributions containing a high fraction of oxygenates, specifically methanol and lesser amounts of C2–C4 alcohols. The high alcohol selectivity, which is atypical for CO hydrogenation over Ru, is ascribed in part to the inhibition of CO dissociation on the metal particles by decoraments provided by the highly basic support.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"167 1","pages":"227-237"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87939578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Reactivity of CO on stepped and non-stepped surfaces of transition metals 过渡金属阶梯和非阶梯表面上CO的反应性

Faraday Discussions of The Chemical Society Pub Date : 1989-01-01 DOI: 10.1039/DC9898700263

D. A. Koster, A. Jansen, V. Santen, J. Geerlings

引用次数: 23