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Controlled synthesis and magnetic properties of Fe_3O_4 walnut spherical particles and octahedral microcrystals

Science china(Technological Sciences) 2008年第11期51卷 1911-1920页

作者： JIAO Hua1,2 & YANG HeQing1 1 Key Laboratory of Macromolecular Science of Shaanxi Province, School of chemistry and Materials Science, Shaanxi Normal university, Xi’an 710062, china 2.department of chemistry and chemical engineering, weinan teachers university, wei nan 71.000, china Key Laboratory of Macromolecular Science of Shaanxi Province School of Chemistry and Materials Science Shaanxi Normal University Xi’an 710062 China department of chemistry and chemical engineering Weinan Teachers University Wei nan 714000 China

Magnetite Fe3O4 walnut spherical particles and octahedral microcrystals were suc- cessfully synthesized from K4 [Fe (CN) 6], K3 [Fe (CN) 6] and NaOH reagents via a simple hydrothermal process. And the uniform morphology of octahedral micro- crystals was obtained in the presence of ethylene glycol. The morphology and structure of products were characterized by powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the Fe3O4 walnut spherical particles and octahedral microcrystals were single crystals with the face-center cubic structure and with size distributions from 2.2 to 8.6 μm and 1.6 to 12.5 μm, respectively. Their magnetic properties were detected by a vibrating sample magnetometer at room temperature. The walnut spherical parti- cles exhibited a ferromagnetic behavior with the coercive force (Hc), saturation magnetization (Ms) and remanent magnetization (Mr) being 150.57 Oe, 97.634 and 12.05 emu/g, respectively. For the octahedral microcrystals they were 75.28 Oe, 101.90 and 6.69 emu/g, respectively. Different sizes of walnut spherical particles were controlled synthesized through adjusting the NaOH concentration. It was found that ethylene glycol molecules have a significant effect on the formation of Fe3O4 octahedra. A possible mechanism was also proposed to account for the growth of these Fe3O4 products

关键词： a hydrothermal route Fe3O4 walnut spherical particles octahedral microcrystals magnetic property

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

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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

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Spectrophotometric Investigation of Cadmium Complex Solutionwith m-Bromobenzenediazoaminoazobenzene

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Chinese chemical Letters 1999年第11期10卷 957-960页

作者： Hong Wen GAO Lei WANG Hao YE(School of chemistry and chemical engineering, Anhui university, Hefei 230039)(department of chemistry, Huaibei Coal teachers College, Huaibei 235000) Anhui Univ Sch Chem & Chem Engn Hefei 230039 Peoples R China Huaibei Coal teachers Coll Dept Chem Huaibei 235000 Peoples R China

The synthesis of a new ligand, m-bromobenzenediazoaminoazobenzene (m-BBDA) was carried out. The reaction between m-BBDA and cadmium(II) was sensitive at pH over 12 and in the presence of emulsifier OP. Because of the high interference of excess of ligand beta-correction theory was applied instead of the single wavelength method. This study gave the simple determination of the complex ratio, real molar absorptivity (epsilon) and step or cumulative stability constant (K).

关键词： beta-correction principle cadmium complex m-bromobenzenediazoaminoazobenzene

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Structural transformation from Waugh-type to Keggin-type polyoxomolybdate-based crystalline material for photo/electrocatalysis

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Rare Metals 2024年第5期43卷 2241-2250页

作者： Pei-Sen Wang Zi-Tong Wang Ya-Ya Tan Peng Chen Xue-Cheng Zhang Lu-nan Zhang Yong-Ge wei Lu-Bin Ni School of chemistry and chemical engineering Yangzhou UniversityYangzhou 225002China Key Lab of Organic Optoelectronics and Molecular engineering of Ministry of Education Department of ChemistryTsinghua UniversityBeijing 100084China State Key Laboratory of Natural and Biomimetic Drugs Peking UniversityBeijing100191China

An inorganicDorganic hybrid crystalline material(SiMo_(12)O_(40))[Cu(2,2'-bipy)_(2)]_(2)·2H_(2)O(Complex 1,2,2'-bipy=2,2'-bipyridine)was synthesized for the first time by using 2,2'-bipy and transition metal copper to convert Waugh-type polyoxometalate[MnMo_(9)O_(3)_(2)]_(6-)into a Keggin polyoxometalate structure[SiMo_(12)O_(40)]^(4-)under hydrothermal conditions in glass *** crystal tests and a series of characterizations were carried out on Complex *** structure of Complex 1 is composed of[SiMo_(12)O_(40)]^(4-)and[Cu^(Ⅱ)(2,2'-bipy)_(2)]^(2+).The five-coordinated Cu is connected to two 2,2'-bipy through CuDN bonds,forming an approximately square ***,Complex 1 exhibited good photocatalytic performance for methylene blue degradation and electrocatalytic nitrite reduction properties simultaneously.

关键词： Polyoxometalates Inorganic-organic hybrid materials Photocatalytic Electrocatalytic

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Internal noise stochastic resonance in CO oxidation on nm-sized palladium particles

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Science china chemistry 2005年第5期48卷 395-401页

作者： GONG Yubing1,2, HOU Zhonghuai1 & XIN Houwen1 1. department of chemical Physics, university of Science and Technology of china, Hefei 230026, china 2. department of Physics, Yantai teachers university, Yantai 264025, china 1. department of chemical Physics University of Science and Technology of China 230026 Hefei China 2. department of Physics Yantai Teachers University 264025 Yantai China

Based on a stochastic mesoscopic model, the influence of internal noise on the oscillatory kinetics of the catalytic oxidation of CO on nm-sized palladium particles is studied, using the chemical Langevin equations, Poisson approximation algorithm, and exact stochastic simulation algorithm. The reaction rate oscillations are of stochastic nature due to considerable internal noise in such mesoscopic systems. It is found that the performance of the stochastic oscillations undergoes a maximum with the variation of internal noise level for a given CO partial pressure, which demonstrates the occurrence of internal noise stochastic resonance. This phe-nomenon implies that optimal internal noise would favor the reaction rate oscillation of CO oxi-dation on nm particles. Such a phenomenon is robust to the change of external parameters, such as CO pressures.

关键词： nanometer-sized palladium particles, surface catalytic CO oxidation, internal noise, stochastic resonance, chemical Langevin equation.

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Stochastic resonance in surface catalytic oxidation of carbon monoxide induced by colored noise

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Science china chemistry 2004年第2期47卷 106-112页

The dynamical behavior of surface catalytic oxidation reaction of Pt(110)/CO+O2 modulated by colored noise, under the condition of specific temperature, has been investigated when the partial pressure of CO gas is near the supercritical Hopf bifurcation point. By computer simulation the oscillation and stochastic resonance induced by colored noise are observed. The influences of the intensity and correlation time of colored noise on stochastic resonance are discussed. The range of sensitivity of the system to the environmental fluctuation is analyzed.

关键词： colored noise, stochastic resonance, surface catalytic reaction of Pt(110)/CO+O2, supercritical Hopf bifurcation, signal-to-noise ratio (SNR).

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Structure of the Manganese (V) Complex-Mn·3/2(μ-DHBQ)·4H_2O·2Cl

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Chinese chemical Letters 2000年第7期11卷 645-648页

作者： Yi Xiang CHENG Mao Lin HU Ji Xin YUAN Yun Chu WANG(department of chemistry & chemical engineering, Southeast university, nanjing 210096 department of chemistry, Wenzhou teachers College, Wenzhou 325003) Dept. of Chem. and Chem. engineering Southeast University Nanjing 210096 China department of chemistry Wenzhou Teachers College Wenzhou 325003 China

The novel complex of Mn(V): Mn·3/2(μ -DHBQ)·4H2O·2Cl (where, H2DHBQ =2,5-dihydroxyl- 1,4-benzoquinone) was synthesized and its crystal structure has been determined by X-ray diffraction. The complex belongs to trigonal system with space group P3(# 147), a= 1 .415(2)nm, c=0.6552(4) nm, V=1 .1371(7) nm-3, Z=2, Dx=1.183 g/cm3, μ=7.37 cm-1, F(000)=408.00,R=0.041, Rw=0.046.

关键词： Manganese (V) crystal structure bridging ligand 2,5-dihydroxyl-1,4-benzoquinone

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ZnGa_(2)S_(4):an infrared nonlinear optical material with large second-harmonic generation response and wide band gap

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Rare Metals 2024年第1期43卷 395-401页

作者： Chen-Yang Zhang Xiao-nan Niu Yan-Feng wei Shu-Xing Zhou Da-Qing Yang Ying Wang Jian Wang Bing-Bing Zhang College of chemistry and Materials Science Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of EducationState Key Laboratory of New Pharmaceutical Preparations and ExcipientsHebei UniversityBaoding 071002China Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and ScienceXiangyang 441053China Hubei Longzhong Laboratory Xiangyang 441000China department of chemistry and Biochemistry Wichita State UniversityKansas 67260USA

High-performance nonlinear optical(NLO)crystals are crucial devices to convert wavelength of solid-state *** play an indispensable role in the research of infrared NLO *** this work,ternary chalcogenide ZnGa_(2)S_(4) ... 详细信息

关键词： optical nonlinear harmonic

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Pictet-Spengler condensation reactions catalyzed by a recyclable H^+-montmorillonite as a heterogeneous BrΦnsted acid

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Science china chemistry 2010年第3期53卷 561-567页

作者： WANG YuFeng,SONG ZhanBo,CHEN ChunXia & PENG JinSong department of chemistry and chemical engineering,College of Science,Northeast Forestry university,Harbin 150040,china 1. department of chemistry and chemical engineering College of Science Northeast Forestry University Harbin 150040 China

Catalytic performance of different cation-exchanged montmorillonite clays has been investigated in the Pictet-Spengler C-C bond forming reaction.H+-Montmorillonite was found to be a very efficient and reusable catalyst for the endo cyclization of β-phenylethylamine derivatives with aldehydes under solvent-free *** addition,an aqueous condensation version for the synthesis of tetrahydro-β-carbolines using the H+-montmorillonite catalyst has been *** these environmentally friendly processes,the use of organic solvents was avoided and the catalyst was recycled with maintenance of high catalytic activity.

关键词： heterogeneous catalysis catalyst recycling mesoporous materials green synthesis

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Ab initio theoretical studies on N_(28),B_4N_(24),B_(12)N_(16), and B_(16)N_(12) with T_d symmetry

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Chinese Journal of chemistry 1996年第6期14卷 490-496页

作者： JIANG, Xin-Tian HU, Xu-Guang LI, Qian-Shu department of chemistry, Shaanxi teachers university, Xi’an, Shanxi 710062, china Institute of Theoretical chemistry, National Laboratory of Theoretical and Computational chemistry, Jilinuniversity, Changchun, Jilin 130023, chinaSchool of chemical engineering and Materials Science, Beijing Institute of Technology, Beijing 100081,china department of chemistry Shaanxi Teachers University Xi'an Shanxi 710062 China Institute of Theoretical chemistry National Laboratory of Theoretical and Computational Chemistry Jilin University Changchun Jilin 130023 China School of chemical engineering and Materials Science Beijing Institute of Technology Beijing 100081 China

Structures, energies and vibrational frequencies have been calculated for hollow cage clusters N28, B4N24, B12N16, and B16N12 with Td symmetry using ab initio quantum mechanical methods at the RHF/3-21G level. Each species is predicted to be both chemically and kinetically stable. Skeletal polyhedrons of all considered boron nitride hollow cage clusters are constructed from 5- and 6-membered rings.

关键词： Nitrogen cluster boron nitride cluster ab initio molecular orbital theory fullerene

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