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Tuning Order-Disorder Phase Transition through Regulating the Substituent Group of Anion

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Chinese Journal of chemistry 2017年第6期35卷 957-963页

作者： Dong Li Lihong Chen Haixia Zhao Lasheng Long Lansun zheng state key laboratory of physical chemistry of solid surfaces and department of chemistry College of Chemistry and Chemieal Engineering Xiamen University Xiamen Fujian 361005 China

The structural phase transition compound {[（CH3）2CHCH2]2NH2}·[Cf3COO] （1） has been synthesized based on the diisobutylamine and trifluoroacetic acid. The DSC data reveal that 1 undergoes a phase transition at 277 K （Tc）. When one chlorine atom replaces one fluorine atom on trifluoroacetate anion, three order-disorder phase transitions at 251 K （Ti）, 282 K （T2） and 290 K could be achieved owing to a stepwise release of rotation motions of the anion and cation in {[（CH3）2CHCH2]2NH2}·[Cf2C[COO] （2）. Based on the variable temperature crystal structures, the phase transition in compound 1 is triggered by the rotation of three fluorine atoms on the trifluoroacetate anion synchronized with the motions of the methyl groups on the diisobutylammonium cation. However, in compound 2, the phase transitions can be realized by a sequence of motions of both the anion and cation. Besides, the dielectric- temperature dependences were investigated in order to prove this regulation process. All of this investigation will be beneficial to design and synthesis of the novel phase transition materials and molecular dielectric materials on pur- pose.

关键词： phase transition dielectric materials order-disorder phase transition structural phase transition

Surfactant dependent evolution of Au-Pd alloy nanocrystals from trisoctahedron to excavated rhombic dodecahedron and multipod： a matter of crystal growth kinetics

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Science Bulletin 2017年第20期62卷 1359-1364页

作者： Qiaoli Chen Guifen Du Yongdi Dong Zhenming Cao Zhaoxiong Xie Lansun zheng state key laboratory of physical chemistry of solid surfaces Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen University Xiamen 361005 China

In wet chemical syntheses of noble metal nanocrystals,surfactants play crucial roles in regulating their *** date,more attention has been paid to the effect of the surfactant on the surface energy of crystal facets,while less attention has been paid to its effect on the growth *** this paper,using the growth of Au-Pd alloy nanocrystals as an example,we demonstrate that different concentration of surfactant hexadecyltrimethyl ammonium chloride(CTAC)may cause the different packing density of CTA+bilayers on different sites(face,edge or vertex)of crystallite surface,which would change the crystal growth kinetics and result in preferential crystal growth along the edge or vertex of *** unique shape evolution from trisoctahedron to excavated rhombic dodecahedron and multipod structure for Au-Pd alloy nanocrystals was successfully achieved by simply adjusting the concentration of *** results help to understand the effect of surfactants on the shape evolution of nanocrystals and open up avenues to the rational synthesis of nanocrystals with the thermodynamically unfavorable morphologies.

关键词： Au-Pd alloy Morphology Nanocrystal Surfactant

Studies of surface processes of electrocatalytic reduction of CO_(2) on Pt(210), Pt(310) and Pt(510)

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Science China chemistry 2007年第5期50卷 593-598页

作者： fAN ChunJie fAN YouJun ZHEN ChunHua zheng QingWei SUN ShiGang state key laboratory of physical chemistry of solid surfaces Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Surface processes of CO_(2)reduction on Pt(210),Pt(310),and Pt(510)electrodes were studied by cyclic *** surface structures of these platinum single crystal electrodes were obtained by various treatment *** experimental results illustrated that the electrocatalytic activity of Pt single crystal electrodes towards CO_(2)reduction is decreased in an order of Pt(210)>Pt(310)>Pt(510),i.e.,with the decrease of(110)step density on well-defined *** the surfaces were reconstructed due to oxygen adsorption,the catalytic activity of all the three electrodes has been enhanced to a cer-tain *** the activity order remains unchanged,the electrocatalytic activity has been en-hanced more significantly as the density of(110)step sites is more intensive on the Pt single crystal *** has revealed that the more open the surface structure is,the more active the Pt single crystal electrode will be,and the easier for the electrode to be transformed into a surface structure that exhib-its higher activity under external ***,the relatively ordered surfaces of Pt single crystal electrode are comparatively stable under the same external *** present study has gained knowledge on the interaction between CO_(2)and Pt single crystal electrode surfaces at a micro-scopic level,and thrown new insight into understanding the surface processes of electrocatalytic re-duction of CO_(2).

关键词： Pt single crystal electrode stepped surface CO_(2)electro-catalyticreduction surface processes

Catalysis under shell： Improved CO oxidation reaction confined in Pt@h-BN core-shell nanoreactors

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Nano Research 2017年第4期10卷 1403-1412页

作者： Mengmeng Sun Qiang fu Lijun Gao Yanping zheng Yangyang Li Mingshu Chen Xinhe Bao state key laboratory of Catalysis iChEM Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China department of Chemical Physics University of Science and Technology of China Hefei230026 China state key laboratory of physical chemistry of solid surfaces Department of Chemistry Xiamen University Xiamen 361005 China

Core-shell nanostructures consisting of active metal cores and protective shells often exhibit enhanced catalytic performance, in which reactants can access a small part of the core surfaces through the pores in the shells. In this study, we show that Pt nanoparticles （NPs） can be embedded into few-layer hexagonal boron nitride （h-BN） overlayers, forming Pt@h-BN core-shell nanocatalysts. The h-BN shells not only protect the Pt NPs under harsh conditions but also allow gaseous molecules such as CO and 02 to access a large part of the Pt surfaces through a facile intercalation process. As a result, the Pt@h-BN nanostructures act as nanoreactors, and CO oxidation reactions with improved activity, selectivity, and stability occur at the core-shell interfaces. The confinement effect exerted by the h-BN shells promotes the Pt-catalyzed reactions. Our work suggests that two-dimensional shells can function as robust but flexible covers on nanocatalyst surfaces and tune the surface reactivity.

关键词： core-shell CO oxidation Pt hexagonal boron nitride nanoreactor

Synthesis and Structure of O-Ethyl S-Hydrogen Isoquinolin-1-ylcarbonothioimidate

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Chinese Journal of Structural chemistry 2006年第5期25卷 604-608页

作者： YU Yun LIN Li-Rong YOU Jun HUANG Rong-Bin zheng Lan-Sun department of chemistry Longyan College Longyan Fujian 364000 China department of chemistry Xiamen University Xiamen 361005 China state key laboratory for physical chemistry of solid surfaces Xiamen University Xiamen 361005 China

O-Ethyl S-hydrogen isoquinolin-l-ylcarbonothioimidate was synthesized and its structure was characterized by IR, MS, ^1H NMR, elemental analysis and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 10.9471（19）, b = 9.3968（17）, c = 10.6125（19） A, β = 100.761 （3）°, V = 1072.5（3） A^3, Z = 4, Dc = 1.439 g/cm^3, f（000） = 488 and μ = 0.279 mm^-1. A total of 7763 reflections were collected, of which 2090 were unique. The structure was refined to the final R = 0.0322 and wR = 0.0882 for 2016 observed reflections with Ⅰ 〉 2σ（Ⅰ）. The crystal structure shows that there are intramolecular N-H…S hydrogen bonds and π-π stacking interactions between adjacent molecules.

关键词： O-ethyl S-hydrogen isoquinolin-1-ylcarbonothioimidate synthesis crystal structure

Spontaneous resolution and absolute chiral induction of 3d-4f heterometal-organic frameworks from achiral precursors

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Science China chemistry 2021年第10期64卷 1698-1702页

作者： Manting Chen Zuochang Chen Huijun Chen Lu Xu Xiangjian Kong Lasheng Long Lansun zheng Collaborative Innovation Center of chemistry for Energy Materials State Key Laboratory for Physical Chemistry of Solid SurfacesDepartment of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

The asymmetric assembly and spontaneous resolution of chiral heterometal-organic frameworks from achiral precursors remain a great challenge. Herein, we report the formation and spontaneous resolution of three-dimensional(3 D) chiral 3 d-4 f heterometal-organic frameworks from achiral ligands in the presence of lactic acid enantiomers as chiral inducers. In the absence of a chiral inducer, the reactants randomly generated both enantiopure crystals in equal measure. However, enantiopure lactic acid induced asymmetric resolution to achieve single chiral crystallization. DfT theoretical calculations showed that the absolute chiral resolution of the enantiomers is due to the difference in the interactions between the two enantiomeric Λ/Δ-[fe L_(3)]^(3-)units and the chiral inducer.

关键词： chirality spontaneous resolution chirality induction heterometal-organic framework achiral precursors

Cross-linkable fullerene interfacial contacts for enhancing humidity stability of inverted perovskite solar cells

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Rare Metals 2021年第7期40卷 1691-1697页

作者： Ming-Wei An Zhou Xing Bao-Shan Wu fang-fang Xie Shan-Yu zheng Lin-Long Deng Xu Wang Bin-Wen Chen Da-Qin Yun Su-Yuan Xie Rong-Bin Huang Lan-Sun zheng state key laboratory for physical chemistry of solid surfaces iChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China College of Energy Xiamen UniversityXiamen 361005China

In situ cross-linking encapsulation has been demonstrated to be an efficient strategy for enhancing the humidity stability of perovskite solar cells(PSCs).In this study,a novel cross-linkable fullerene derivative,namely1-(p-benzoate-(p-methylvinylbenzene)-indolino[2,3][60]fullerene(fPPS),was readily synthesized from commercially available building blocks in two *** fPPS was employed as an interfacial modifier on perovskite surfaces in inverted planar p-i-n *** to the fast interfacial charge extraction and efficient trap passivation,PSCs based on the cross-linked fPPS(C-fPPS)exhibited excellent *** PSCs had a top-performing power conversion efficiency(PCE)of 17.82%with negligible hysteresis,compared to the control devices without C-PffS(16.99%).Moreover,the strong water resistance of the C-fPPS interfacial layer distinctly enhances the ambient stability of PSC devices,exhibiting a t80(the time required to reach 80%of the initial PCE)of 300 h under high-humidity *** significantly surpasses the control devices,whose t80 was only 130 *** results demonstrate that cross-linkable fullerene derivatives can be promising interfacial materials for designing high-efficiency,hysteresis-free,air-stable PSCs.

关键词： Perovskite solar cells Cross-linkable fullerene fullerene interlayer Power conversion efficiency Humidity stability

PtCu subnanoclusters epitaxial on octahedral PtCu/Pt skin matrix as ultrahigh stable cathode electrocatalysts for room-temperature hydrogen fuel cells

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Nano Research 2023年第2期16卷 2252-2258页

作者： fengling Zhao Lirong zheng Qiang Yuan Qinghua Zhang Tian Sheng Xiaotong Yang Lin Gu Xun Wang state-Local Joint laboratory for Comprehensive Utilization of Biomass Center for R&D of Fine ChemicalsCollege of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China Beijing Synchrotron Radiation facility Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China key Lab of Organic Optoelectronics&Molecular Engineering Tsinghua UniversityBeijing 100084China College of chemistry and Materials Science Anhui Normal UniversityWuhu 241000China Chinese Academy of Sciences and Beijing National laboratory for Condensed Matter Physics Beijing 100190China

Achieving stable surface structures of metal catalysts is an extreme challenge for obtaining long-term durability and meeting industrial application *** report a new class of metal catalyst,Pt-rich PtCu heteroatom subnanoclusters epitaxially grown on an octahedral PtCu alloy/Pt skin matrix(PtCu1.60),for the oxygen reduction reaction(ORR)in an acid *** PtCu1.60/C exhibits an 8.9-fold enhanced mass activity(1.42 A·mgPt^(−1))over that of commercial Pt/C(0.16 A·mgPt^(−1)).The PtCu1.60/C exhibits 140,000 cycles durability without activity decline and surface PtCu cluster stability owing to unique structure derived from the matrix and epitaxial growth pattern,which effectively prevents the agglomeration of clusters and loss of near-surface active *** characterization and theoretical calculations confirm that Pt-rich PtCu clusters favor ORR activity and thermodynamic *** room-temperature polymer electrolyte membrane fuel cells,the PtCu1.60/C shows enhanced performance and delivers a power density of 154.1/318.8 mW·cm^(−2)and 100 h/50 h durability without current density decay in an air/O_(2)feedstock.

关键词： epitaxial growth core–shell nanostructure PtCu alloy oxygen reduction reaction hydrogen fuel cells

Magnetoelectric effect generated through electron transfer from organic radical to metal ion

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National Science Review 2023年第4期10卷 133-141页

作者： Xiaolin Liu Qiang Liu Haixia Zhao Guilin Zhuang Yanping Ren Tao Liu Lasheng Long Lansun zheng Collaborative Innovation Center of chemistry for Energy Materials State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University state key laboratory of fine Chemicals Dalian University of Technology College of Chemical Engineering Zhejiang University of Technology

Magnetoelectric(ME) materials induced by electron transfer are extremely rare. Electron transfer in these materials invariably occurs between the metal ions. In contrast, ME properties induced by electron transfer from an organic radical to a metal ion have never been observed. Here, we report the ME coupling effect in a mononuclear molecule-based compound [(CH3)3NCH2CH2Br][fe(Cl2An)2(H2O)2](1)[Cl2An = chloranilate,(CH3)3NCH2CH2Br+=(2-bromoethyl)trimethylammonium]. Investigation of the mechanism revealed that the ME coupling effect is realized through electron transfer from the Cl2An to the fe ion. Measurement of the magnetodielectric(MD) coefficient of 1 indicated a positive MD of up to ～12% at 103.0Hz and 370 K, which is very different from that of ME materials with conventional electron transfer for which the MD is generally negative. Thus, the current work not only presents a novel ME coupling mechanism, but also opens a new route to the synthesis of ME coupling materials.

关键词： molecular ferroelectric electron transfer radical magnetoelectric effect