检索结果-南通市图书馆

Cotton pads-derived carbon materials/reduced graphene oxide modified with polypyrrole for electrode of supercapacitors

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第7期94卷 41-53页

作者： Ofelia MArias-Pinedo Elvis OLopez Ivonne EMonje RSoria-Martinez Antony Bazan-Aguilar Clemente Alfredo Luyo Caycho Gabriel Angel Planes Angelica Maria Baena-Moncada Laboratorio de Investigacion de Electroquimica Aplicada Facultad de Ciencias de la Universidad Nacional de IngenieriaAv.Tupac Amaru 210RimacLimaPeru department of Experimental Low Energy Physics Brazilian Center for Research in Physics(CBPF)Rio de Janeiro22290-180Brazi Universidad Tecnologica del Peri Av.Arequipa 26515046 LimaPeru Centeror theevelopmentof Adanced Materials and Nanotechlogy Universidad NacionaldeIngeneria33LimaP departamento de quimica Universidad Nacional de Rio CuartoInstituto de Investigaciones en Tecnologias Energeticas y Materiales Avanzados(IITEMA)Ruta Nac.36Km 601(X5804BYA)RioCuartoCordobaArgentina

This study investigates the influence of electropolymerization conditions on the deposition of polypyrrole(PPy)onto cotton-derived carbon fiber(CF)modified with reduced graphene oxide(rGO)for supercapacitors applications using an experimental/theorical *** surface modification of CF by rGO and/or by PPy electrodeposited at 10,25 and 50 mV s^(-1) was thoroughly examined physicochemical and *** electrodes comprising CF-rGo-PPy,synthesized via electropolymerization at 25 mV s^(-1),demonstrated a remarkable increase in capacitance,showcasing~742 F g^(-1) compared to 153 F g^(-1) for ***,N_(2)-surface area,XPS,and TD-DFT approach revealed that the higher capacitance observed in CF-rGo-PPy electrodes underscores the influence of morphology and charged nitrogen species on the electrochemical performance of these modified ***,this electrode material achieves a specific capacitance retention of~96%of their initial capacitance after 10000 cycles at 0.5 A g^(-1) measured in a two-electrodes cell *** work also discusses the influence of the scan rate used for pyrrole electropolymerization on the pseudocapacitance contribution of PPy and its possible effect on the porosity of the *** results highlight the importance of appropriate electropolymerization conditions that allow obtaining the synergistic effect between CF,rGO and PPy.

关键词： Supercapacitors Cotton pads-derived carbon fibers rGO PPy TD-DFT

Biomass valorization via electrocatalytic carbon–carbon bond cleavage

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第4期91卷 542-578页

作者： Keping Wang Zhenyan Guo Min Zhou Ying Yang Lanyun Li Hu Li Rafael Luque Shunmugavel Saravanamurugan National Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide&Agricultural BioengineeringMinistry of EducationState-Local Joint Laboratory for Comprehensive Utilization of BiomassCenter for R&D of Fine ChemicalsGuizhou UniversityGuiyang 550025GuizhouChina departamento de quimica Organica Universidad de CordobaCampus de RabanalesEdificio Marie Curie(C-3)Ctra Nnal IVKm.396E-14014 CordobaSpain Laboratory of Bioproduct Chemistry Centre of Innovative and Applied Bioprocessing(CIAB)Mohali 140306PunjabIndia

Renewable electrocatalytic upgrading of biomass feedstocks into valuable chemicals is one of the promising strategies to relieve the pressure of traditional energy-based *** electrocatalytic carbon–carbon bond cleavage of high selectivity,various functionalized molecules,such as organic acids,amides,esters,and nitriles,have great potential to be accessed from ***,it has merely received finite concerns and interests in the *** review first showcases the research progress on the electrocatalytic conversion of lipid/sugar-and lignin-derived molecules(e.g.,glycerol,mesoerythritol,xylose,glucose,1-phenylethanol,and cyclohexanol)into organic acids via specific carbon–carbon bond scission processes,with focus on disclosing reaction mechanisms,recognizing actual active species,and collecting feasible modification *** the guidance of further extensive studies on biomass valorization,organic transformations via a variety of reactions,including decarboxylation,ring-opening,rearrangement,reductive hydrogenation,and carboxylation,are also disclosed for the construction of similar carbon skeletons/*** remaining challenges,prospective applications,and future objectives in terms of biomass conversion are also *** review is expected to provide references to develop renewed electrocatalytic carbon–carbon bond cleavage transformation paths/strategies for biomass upgrading.

关键词： Electrocatalysis Biomass conversion Carbon-carbon bond cleavage Organic acids

Solid-state synthesis of LnOCl/Ln_2O_3(Ln=Eu, Nd) by using chitosan and PS-co-P4VP as polymeric supports

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2018年第12期36卷 1326-1332页

作者： C.Diaz D.Carrillo R.de la Campa A.Presa Soto M.L.Valenzuela departamento de quimica Facultad de Quimica Universidad de Chile departamento de quimica Organica e Inorganica (IUQOEM) Facultad de Quimica Universidad de Oviedo Universidad Autonoma de Chile Facultad de Ingenieria Instituto de Ciendas Quimicas Aplicadas Inorganic Chemistry and Molecular Material Center

A series of lanthanide materials of type LnOCl or Ln2O3(Ln = Eu, Nd) were successfully prepared via a convenient and straightforward two-step procedure. Firstly, and by using chitosan and PS-co-P4 VP as polymeric supports, macromolecular complexes of type chitosan ·LnCl3and PS-co-P4 VP·LnCl3 were prepared. These macro molecular complexes were treated in solid state at 800 ℃ under air, leading to the corresponding LnOCl or Ln2O3materials(Ln = Eu, Nd) with moderate to good yields. The nature of the asprepared lanthanide materials(LnOCl and/or Ln2O3) is strongly influenced by the polymeric template(i.e.,chitosan or PS-co-P4 VP), the lanthanide salt precursor, and the polymer/lanthanide molar ratio. Thus, when chitosan · EuCl3and PS-co-P4 VP·EuCl3are used as macromolecular precursors, a mixture of crystalline phases of both EuOCl and Eu2O3are obtained. However, when chitosan· NdCl3and PS-co-P4 VP· NdCl3are used, a sole pure crystalline phase of NdOCl is obtained. The nano structured lanthanide materials were characterized by means of XRD(X-ray diffraction of powder), SEM, EDS, TEM, and HRTEM. The luminescent spectra of the asprepared EuOCI/Eu2O3mixture materials show an emission pattern whose intensity is strongly influenced by the nature of the polymeric precursor, as well as on the metal/polymer molar ratios.

关键词： EuOCl/Eu_2O_3 NdOCl Solventless method Luminescence Lanthanides Rare earths

Production of carbonaceous material from avocado peel for its application as alternative adsorbent for dyes removal

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2016年第4期24卷 521-528页

作者： Carolyn Palma Lucia Lloret Antonio Puen Maira Tobar Elsa Contreras departamento de Ingenieria quimica Ambiental Universidad Tecnica Federico Santa Mafia Vicunia Mackenna 3939 Santiago Chile departamento de Ingenieria quimica Universidad de Santiago de Chile Alameda 3363 Santiago Chile

Adsorption processes have received special attention for contaminants removal thanks to their capability to gen- erate effluents with high quality as well as their simple design. In the current work, the agro-waste residue avo- cado peel is proposed to be used as alternative to conventional activated carbons whose use is sometimes restricted to high costs, upgraded by their exhausting after long term operations. The carbonization procedure was optimized and analyzed through factorial design and response surface methodology by evaluating temper- ature （400-900 ℃） and time （30-90 min） effects： optimal conditions were found at 900℃ and 65 min, gener- ating an adsorbent with 87.52 m2.g 1 of BET surface area, a mesopore volume of 74% and a zero point charge at 8.6. The feasibility of the carbonaceous material was proved for the removal of a variety of dyes by investigating substrate （10-50 mg.L 1） and solid （0.5-20 g.L-1） concentration effects and statistical significance： complete removal of Naphthol Blue Black and Reactive Black 5 was reached under optimal conditions （10 mg.L 1 and 20g.L 1 of dye and solid, respectively）, while Basic Blue 41 was eliminated by using 13.4 g. L- 1 of the adsorbent. Overall, dyes removal by adsorption on carbonized avocado peel is presented as a promising technology due to the low cost and easy availability of the precursor, as well as the straightforward generation, the satisfactory char- acteristics and the proved adsorption capacity of the adsorbent.

关键词： Avocado peelCarbonizationOptimizationAdsorptionDyes

Hadron resonances as rovibrational states

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2021年第8期45卷 99-104页

作者： Douglas L.Bernardo Cristiano C.Bastos Antonio C.Pavao departamento de quimica Fundamental Universidade Federal de PernambucoRecife50740-540Brazil departamento de quimica Universidade Federal Rural de PernambucoRecife52171-900Brazil

A rovibrational model,including anharmonic,centrifugal,and Coriolis corrections,is used to calculate π,K,N,and ∑ orbital and radial *** four orbital excitations of the n meson correspond to the/?(1235),ti2(1670),63(2030),and π4(2250)*** first four radial excitations correspond to the π(1300),π(1800),π(2070),and 7t(2360)*** orbital excitations of the K meson are interpreted as the K_(1)(1270),K_(2)(1770),K_(3)(2320),and K_(4)(2500)resonances;its radial excitations correspond to the K(1460)and K(1830)*** N orbital excitations are identified with the N(1520),N(1680),N(2190),N(2220),and N(2600)*** first four radial excitations of the N family correspond to the N(1440),N(1880),N(2100),and N(2300)*** orbital excitations of the ∑ baryon are associated with the ∑(1670),∑(1915),∑(2100),and ∑(2250)resonances,whereas its radial excitations are identified with the ∑(1660),∑(1770),and ∑(1880)*** proposed rovibrational model calculations show a good agreement with the corresponding experimental values and allow for the prediction of hadron resonances,thereby proving to be useful for the interpretation of excited hadron spectra.

关键词： excited hadron spectrum orbital and radial resonances rovibrational states

Molecular modeling of the octacoordinated tetracarbonato-Nd(III), [Nd(CO_3)_4]^(5-), complex and its nonacoordinated fluoro- and aquo-adducts

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2010年第6期28卷 847-853页

作者： S. P. Sinha Alfredo M. Simas Gustavo L. C. Moura Scientific Research & development departamento de quimica Fundamental CCEN Universidade Federal de Pernambuco

Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)***2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(CO3)4·F2]7-and [Nd(CO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.

关键词： lanthanides theoretical molecular models octacoordination carbonato complexes adducts MOPAC SPARKLE rare earths

Quantitative Electrophilicity Measures

在线全文

学校读者我要写书评

暂无评论

物理化学学报 2018年第6期34卷 662-674页

作者： GONZáLEZ Marco Martínez CáRdeNAS Carlos RODRíGUEZ Juan I. LIU Shubin HEIDAR-ZAdeH Farnaz MIRANDA-QUINTANA Ramón Alain AYERS Paul W. Laboratory of Computational and Theoretical Chemistry Faculty of Chemistry University of Havana Havana 10400 Cuba. departamento de quimica and Centro de Quimica Universidade de Coimbra 3004-535 Coimbra Portugal. departamento de Fisica Fac

Quantitative correlation of several theoretical electrophilicity measures over different families of organic compounds are examined relative to the experimental values of Mayr et ***,the ability to predict these values accurately will help to elucidate the reactivity and selectivity trends observed in charge-transfer reactions.A crucial advantage of this theoretical approach is that itprovides this information without the need of experiments,which are often demanding and ***,two different types of electrophilicity measures were ***,models derived from conceptual density functional theory(c-DFT),including Parr's original proposal and further generalizations of this index,are *** instance,the approaches of Gázquez et *** Chamorro et *** considered,whereby it is possible to distinguish between processes in which a molecule gains or loses ***,we also explored two novel electrophilicity *** one hand,the potential of environmental perturbations to affect electron incorporation into a system is analyzed in terms of recent developments in *** studies highlight the importance of considering the molecular surroundings when a consistent description of chemical reactivity is *** the other hand,we test a new definition of electrophilicity that is free from inconsistencies(so-called thermodynamic electrophilicity).This approach is based on Parr's pioneering insights,though it corrects issues present in the standard working expression for the calculation of ***,we use machine-learning tools(i.e.,symbolic regression) to identify the models that best fit the experimental *** this way,the best possible description of the electrophilicity values in terms of different electronic structure quantities is ***,this straightforward approach enables one to obtain good correlations between the theoretical and experimental quantities by using the simple,yet p

关键词： Electrophilicity Conceptual density functional theory Symbolic regression Genetic programming Grammatical evolution

Reactivity of Indoles through the Eyes of a Charge-Transfer Partitioning Analysis

在线全文

学校读者我要写书评

暂无评论

物理化学学报 2018年第6期34卷 692-698页

作者： OROZCO-VALENCIA Ulises GáZQUEZ José L. VELA Alberto departamento de quimica Centro de Investigacion y de Estudios Avanzados Av. Instituto Politecnico Nacional 2508 Colonia San Pedro Zacatenco Ciudad de Mexico 07360 Mexico. departamento de quimica Universidad Autonoma Metropolitana-Iztapalapa

A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert *** and Robert ***,which introduces two charge transfer channels(one for accepting electrons(electrophilic) and another for donating(nucleophilic)),is applied to the reaction of a set of indoles with 4,*** global analysis indicates that the prevalent electron transfer mechanism in the reaction is a nucleophilic one on the indoles,i.e.,the indoles under consideration transfer electrons to 4,*** the reactivity descriptorswith exchange-correlation functionals including exact exchange(global hybrids) yields slightly better correlations than those obtained with generalized gradient-approximated functionals;however,the trends are *** the trend obtained with the number of electrons donated by the indoles,and predicted by the partitioning model,with that observed experimentally based on the measured rate constants,we propose that the number of electrons transferred through this channel can be used as a nucleophilicity scale to order the reactivity of indoles towards 4,*** approach to obtain reactivity scales has the advantage of depending on the intrinsic properties of the two reacting species;therefore,it opens the possibility that the same group of molecules may show different reactivity trends depending on the species with which they are *** local model allows systematic incorporation of the reactive atoms based on the their decreasing condensed Fukui functions,and the correlations obtained by increasing the number of reactive atoms participating in the local analysis of the transferred nucleophilic charge improve,reaching an optimal correlation,which in the present case indicates keeping three atoms from the indoles and two from 4,*** atoms selected by this procedure provide valuable information about the local reactivity of the indoles.W

关键词： Chemical reactivity Conceptual DFT Charge transfer Nucleophilicity Indoles Transition state prediction

Manifestation of external field effect in time-resolved photo-dissociation dynamics of LiF

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2013年第7期22卷 140-147页

作者：孟庆田 A. J. C. Varandas department of Physics Institute of Physics and ElectronicsShandong Normal University departamento de quimica Universidade de Coimbra

The photo-dissociation dynamics of LiF is investigated with newly constructed accurate ab initio potential energy curves （PECs） using the time-dependent quantum wave packet method. The oscillations and decay of the wave packet on the adiabats as a function of time are given, which can be compared with the femtosecond transition-state （FTS） spectroscopy. The photo-absorption spectra and the kinetic-energy distribution of the dissociation fragments, which can exhibit the vibration-level structure and the dispersion of the wave packet, respectively, are also obtained. The investigation shows a blue shift of the band center for the photo-absorption spectrum and multiple peaks in the kinetic-energy spectrum with increasing laser intensity, which can be attributed to external field effects. By analyzing the oscillations of the wave packet evolving on the upper adiabat, an approximate inversion scheme is devised to roughly deduce its shape.

关键词： photo-dissociation dynamics time-dependent wave packet method photo-absorption spectra external field effect