检索结果-南通市图书馆

“Buckets effect”in the kinetics of electrocatalytic reactions

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第2期89卷 388-396,I0010页

作者： Haowen Cui Yan-Xia Chen hefei national laboratory for physical sciences at microscale Department of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic *** results demonstrate a rectangular hyperbolic relationship,i.e.,the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant *** consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution,which determines the upper limit of ORR kinetics.A model of effective concentration is further proposed for rectangular hyperbolic relationships:when the reactant concentration is high enough to reach a critical saturation concentration,the effective reactant concentration will become a constant *** could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the *** study provides new insights into the kinetics of electrocatalytic reactions,and it is important for the proper evaluation of catalyst activity and the study of structureperformance relationships.

关键词： Oxygen reduction reaction Kinetics Zero order Rectangular hyperbolic relationship pH effect

Deciphering the linear relationship in the activity of the oxygen reduction reaction on Pt electrodes:A decisive role of adsorbates

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第7期94卷 70-77页

作者： Haowen Cui Yan-Xia Chen hefei national Research Center for physical sciences at microscale and department of chemical physics University of Science and Technology of ChinaHefei 230026AnhuiChina

Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ***,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)*** results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the *** finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR *** support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine *** further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR *** study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.

关键词： Oxygen reduction reaction Activity Adsorbate Equilibrium potential Pt(111)

Dynamic kinetic stereodivergent transformations of propargylic ammonium salts via dual nickel and copper catalysis

在线全文

学校读者我要写书评

暂无评论

Chinese chemical Letters 2024年第8期35卷 265-269页

作者： Ruilong Geng Lingzi Peng Chang Guo hefei national laboratory for physical sciences at the microscale and department of Chemistry University of Science and Technology of ChinaHefei 230026China

The dynamic kinetic asymmetric transformation of racemic propargylic ammonium salts with prochiral aldimine esters through a stereodivergent propargylation is catalyzed by dual nickel and copper ***,a diverse range of optically activeα-quaternary amino esters were produced via C-N bond cleavage with high reaction efficiency and stereoselectivity(up to>99%ee).By selection of the appropriate pair-wise combination of catalyst configurational isomers,all four possible stereoisomers of the corresponding propargylation products are obtained in high yields with excellent regio-,diastereo-,and enantioselectiv-ities.

关键词： Stereodivergent propargylation Dual catalysis C-N bond cleavage Azaomethine ylides Internal propargylic ammonium salts Excellent stereoselectivity

Surface evolution of thermoelectric material KCu_(4)Se_(3) explored by scanning tunneling microscopy

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2024年第8期33卷 422-427页

作者：夏玉敏马妮蔡德胜刘宇舟谷易通于淦霍思宇庞文慧肖翀秦胜勇 International Center for Quantum Design of Functional Materials(ICQD) Hefei National Laboratory for Physical Sciences at Microscale(HFNL)University of Science and Technology of ChinaHefei 230026China CAS Key laboratory of Strong Coupled Quantum Matter physics Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China hefei national laboratory for physical sciences at the microscale University of Science and Technology of ChinaHefei 230026China Institute of Energy Hefei Comprehensive National Science CenterHefei 230031China Dalian national laboratory for Clean Energy Chinese Academy of Sciences(CAS)Dalian 116023China hefei national laboratory University of Science and Technology of ChinaHefei 230088China

Novel two-dimensional thermoelectric materials have attracted significant attention in the field of thermoelectric due to their low lattice thermal conductivity.A comprehensive understanding of their microscopic structures is crucial for driving further the optimization of materials properties and developing novel functional ***,by using in situ scanning tunneling microscopy,we report the atomic layer evolution and surface reconstruction on the cleaved thermoelectric material KCu_(4)Se_(3) for the first *** clearly revealed each atomic layer,including the naturally cleaved K atomic layer,the intermediate Se^(2-)atomic layer,and the Se^(-)atomic layer that emerges in the thermodynamic-stable *** from the maj ority of studies that predominantly concentrate on macroscopic measurements of the charge transport,our results reveal the coexistence of potassium disorder and complex reconstructed patterns of selenium,which potentially influences charge carrier and lattice *** results provide direct insight into the surface microstructures and evolution of KCu_(4)Se_(3),and shed useful light on designing functional materials with superior performance.

关键词： thermoelectric KCu_(4)Se_(3) scanning tunneling microscopy(STM) evolution

Synthesis of hierarchically porous carbon materials by zinc salts-assisted carbonization of biomass and organic solid wastes

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第1期84卷 45-52页

作者： Le-Le Zhang Lei Tong Yanwei Ding Wanqun Zhang Hai-Wei Liang hefei national Research Center for physical sciences at the microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei230026China

Hierarchically porous carbons(HPCs)with multimodal pores have attracted considerable attention due to their unique physical and chemical properties and various application potentials in heterogeneous catalysis,environmental treatment,and energy storage and ***,we report a general and simple zinc salts-assisted method for the synthesis of HPCs with varied porosity and chemical func-tionalities by the direct carbonization of diverse biomass and *** the carbonization,zinc salts are thermally decomposed into nanoparticles that serve as in-situ templates to introduce nanopores in *** prepared HPCs exhibit high specific surface areas(up to 2432 m2 g-1),large pore volumes(up to 4.30 cm^(3)g^(-1)),and broad pore size ***,the zinc salts can be recovered and recycled,supporting the sustainable production of HPCs on large *** prepared HPCs-supported catalysts with atomically dispersed metal sites exhibit promising electrocatalytic performance for the oxygen reduction reaction.

关键词： Hierarchical porous carbon Zinc salts Biomass Wastes Electrocatalysis

Room-temperature ferrimagnetism and size-modulated electronic structures in two-dimensional cluster-based metal-organic frameworks

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

Science China Chemistry 2024年第4期67卷 1334-1340页

作者： Jing Cheng Xingxing Li Jinlong Yang Key laboratory of Precision and Intelligent Chemistry University of Science and Technology of ChinaHefei 230026China department of chemical physics University of Science and Technology of ChinaHefei 230026China hefei national Research Center for physical sciences at the microscale University of Science and Technology of ChinaHefei 230026China hefei national laboratory University of Science and Technology of ChinaHefei 230088China

Cluster-assembled materials have attracted particular attention for their complex hierarchical structures and unique ***,the majority of cluster-based assemblies developed so far are either non-magnetic or only exhibit magnetic ordering with a relatively low Curie temperature,limiting their applications in ***,two-dimensional(2D)cluster-assembled materials with room-temperature magnetism remain highly *** this purpose,based on first principles calculations,we design a series of thermodynamically stable 2D cluster-based metal-organic frameworks(MOFs)Fe_(n)-(pyz)(n=1-6)by utilizing Fenmetal clusters as nodes and nitrogen-containing pyrazine ligands as organic *** 2D cluster-based MOFs exhibit robust ferrimagnetic ordering due to the strong d-p direct exchange interaction between d-electron spin of Fe_(n)(n=1-6)clusters and charge transfer-induced p-electron spin of pyrazine *** particular,the ferrimagnetic Curie temperatures are well above room temperature(up to 836 K).Additionally,altering the size of Fe_(n)clusters in Fe_(n)-(pyz)(n=1-6)MOFs results in diverse functional spintronic properties,including bipolar magnetic semiconductors,half semiconductors and Dirac half ***,these 2D assembled MOFs possess sizable magnetic anisotropy energies,up to 9.16 me V per formula.

关键词： metal-organic framework two-dimensional material half metal bipolar magnetic semiconductor magnet

Computational design of bimetallic Tm_(2)@g-C_(9)N_(4)electrocatalysts for enhanced CO reduction toward C_(2)products

在线全文

学校读者我要写书评

暂无评论

Chinese chemical Letters 2024年第7期35卷 484-490页

作者： Jiajun Wang Guolin Yi Shengling Guo Jianing Wang Shujuan Li Ke Xu Weiyi Wang Shulai Lei Tianjin Key laboratory of Structure and Performance for Functional Molecules College of ChemistryTianjin Normal UniversityTianjin 300387China department of chemical physics&hefei national laboratory for physical sciences at microscale University of Science and Technology of ChinaHefei 230026China Hubei Key laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and ScienceXiangyang 441053China Hubei Longzhong laboratory Xiangyang 441053China

Electrochemical CO reduction(ECOR)as a potential strategy for producing valuable chemicals and fuels has captured substantial ***,the currently available electrocatalysts suffer from poor selectivity and low Faradaic efficiency,limiting their industrial ***,we systematically investigate the potential of homonuclear bimetallic electrocatalysts,Tm_(2)@C_(9)N_(4)(TM=Fe,Co,Ni,and Cu),for the ECOR through extensive density functional theory *** findings suggest that all four proposed monolayers exhibit exceptional stability,making them highly suitable for experimental synthesis and practical ***,these transition-metal dual atoms anchored on C_(9)N_(4)monolayers show great potential in facilitating the production of high-value C_(2)products,such as C_(2)H_(5)OH and C_(2)H_(4),due to the significantly low limiting potentials(-0.06~-0.46 V)and small kinetic energy barriers(0.54–1.08 eV)for the CO coupling ***,with the exception of Ni_(2)@C_(9)N_(4),these bimetallic catalysts demonstrate the impressive suppression of the competitive hydrogen evolution reaction(HER),leading to a high selectivity for C_(2)products in *** predictions would accelerate the development of high-performance C_(9)N_(4)-based dual-atom catalysts for the ECOR.

关键词： C_(9)N_(4)monolayer Double-atom catalysts CO electroreduction Multi-carbon products Density functional theory

Alloy strategy to synthesize Pt-early transition metal oxide interfacial catalysts

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 3390-3397页

作者： Shi-Long Xu Hang Nan Wanqun Zhang Yue Lin Sheng-Qi Chu Hai-Wei Liang hefei national Research Center for physical sciences at the microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei 230026China School of Materials and chemical Engineering Anhui Jianzhu UniversityHefei 230601China Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China

Metal oxide supported metal catalysts show promising catalytic performance in many industry-relevant ***,the enhancement of performance is often limited by the insufficient metal/metal oxide *** this work,we demonstrate a general synthesis of Pt-early transition metal oxide(Pt-MO_(x),M=Ti,Zr,V,and Y)catalysts with rich interfacial sites,which is based on the air-induced surface segregation and oxidation of M in the supported Pt-M alloy *** characterizations verify the dynamic structural response of Pt-M alloy catalysts to air and the formation of Pt-MO_(x) catalysts with abundant interfacial *** prepared Pt-TiO_(x) interfacial catalysts exhibit improved performance in hydrogenation reactions of benzaldehyde,nitrobenzene,styrene,and furfural,as a result of the heterolytic dissociation of H_(2) at Pt-metal oxide interfacial sites.

关键词： Pt-early transition metal oxide interfacial catalyst alloy oxidation strategy interfacial sites hydrogenation reactions heterolytic dissociation

Preparing cyclic polymers at high concentrations via self-folding cyclization technique by adjusting the contents of hydrophilic units in linear precursors

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

Chinese chemical Letters 2024年第2期35卷 283-288页

作者： Hao Zha Zuowei Wang Chao Liu Chunyan Hong department of Polymer Science and Engineering University of Science and Technology of ChinaHefei 230026China hefei national laboratory for physical sciences at the microscale University of Science and Technology of ChinaHefei 230026China

Cyclic polymers are a class of polymers that feature endless topology,and the synthesis of cyclic polymers has attracted the attention of many ***,cyclic polymers were efficiently constructed by self-folding cyclization technique at high *** poly((oligo(ethylene glycol)acrylate)-co-(dodecyl acrylate))(P(OEGA-co-DDA))precursors with different ratios of hydrophilic and hydrophobic moieties were synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization using a bifunctional chain transfer agent with two anthryl end *** amphiphilic linear precursors underwent the self-folding process to generate polymeric nanoparticles in *** irradiating the aqueous solution of the nanoparticles with 365 nm UV light,cyclic polymers were synthesized successfully via coupling of anthryl *** effects of the ratios of hydrophilic and hydrophobic moieties in linear P(OEGA-co-DDA)copolymers and polymer concentration on the purity of the obtained cyclic polymers were explored in detail via ^(1)H nuclear magnetic resonance(^(1)H NMR),dynamic light scattering(DLS),UV‒visible(vis)analysis,three-detection size exclusion chromatography(TD-SEC)and transmission electron microscopy(TEM).It was found that by adjusting the content of the hydrophilic segments in linear precursors,single chain polymeric nanoparticles(SCPNs)can be generated at high polymer ***,cyclic polymers with high purity can be constructed *** method overcomes the limitation of traditional ring-closure method,which is typically conducted in highly dilute conditions,providing an efficient method for the scalable preparation of cyclic polymers.

关键词： Cyclic polymers Self-folding cyclization technique Single chain polymeric nanoparticles RAFT polymerization Direct visualization