金属有机骨架（MOFs）/纤维材料用于电阻式气体传感器的研究进展

总结了将MOFs材料与金属氧化物、纺织品以及碳基导电纤维材料相结合,并在电阻式气体传感器领域的研究与应用。其中金属氧化物结合MOFs过程中,MOFs主要有两个作用:一是作为分散剂提高金属氧化物的分散性;二是利用MOFs本身具有较大的比表面积和大量的活性位点,来提高材料对于气体分子的吸附量和选择性。当纺织品与MOFs结合的过程中,由于纺织品的导电性相对较差,所以需要结合一些导电性及气体选择性较好的MOFs来作为传感器。碳基导电纤维一般具有较好的机械性能和导电性能,因此将其与MOFs材料复合后用于柔性电阻气体传感器具有一定的优势。      

Enhanced photocatalytic performance of SrTiO_3 powder induced by europium dopants

In this work,Eu~(3+)doped SrTiO_3 powders were synthesized by sol-gel method and the influences of Eu~(3+)dopants on the crystalline structure,micro structure mo rphology,electronic band-gap and photocatalytic performance for degradation of o rganic pollutant were investigated in detail.Research results reveal that the incorporated Eu3+ions in SrTiO_3 lattice are preferable to substitute the Sr~(2+)-Ti4+ions pair by two Eu3+ions.The presence of Eu3+ions plays a significant role for the microstructure morphology of the S rTiO_3 powders,leading to the formation of smaller size nanoparticles with a higher specific surface area.The light absorption capability of the resulting materials is improved owing to the narrowing of the band-gap induced by Eu3+dopants.As a result,the enhanced photocatalytic activity application for photodegradation of Rhodamine B solution is demonstrated for the SrTiO_3 powders doped with Eu3+ions.     

Novel luminescent europium-centered hybrid material covalently grafted with organically modified titania via 2-substituted imidazophenanthroline for fluorescence sensing

By employing a rational approach,we prepared a novel kind of luminescent europium-centered hybrid material named Eu(tta)_3NCP-TiO_2.The resulting material was characterized by FT-IR spectra,SEM,X-ray diffraction,thermogravimetric analysis,and photoluminescence spectra.The hybrid material features the combined advantages of the europium complex and the titania host,exhibiting not only good thermostability,but also long luminescence lifetime.Owing to the excellent luminescence of this material,the application in detecting organic small molecule solvents and metal ions was explored systematically.Significantly,Eu(tta)_3 NCP-TiO_2 exhibits superior detection for nitrobenzene molecule and Cu~(2+) ion in DMF(N,N-dimethylformamide) medium.Furthermore,the limit of detection(LOD) of Eu(tta)_3 NCP-TiO_2 for nitrobenzene and Cu~(2+) ion can be counted as 5.593× 10~(-5) and 9.566 ×10~(-5) mol/L,respectively.The results demonstrate that Eu(tta)_3 NCP-TiO_2 can serve as an efficient fluorescence probe for the detection of sensing of nitrobenzene and Cu~(2+) ion.     

Self-luminescence and color-tunable emission in KYb_3F_(10) matrix under different excited sources

A self-luminescence KYb_3 F_(10) material was obtained via a mild hydrothermal method.Its structure,morphology and the corresponding luminescence properties were studied.There is a self-luminesce nce based on the effective recombination of electron and hole on surface defects or electronic centers in KYb_3 F_(10).The pH values have significant impact on crystallinity and self-luminescent intensity of target products.With the introduction of Tb~(3+)and Eu~(3+)into KYb_3 F_(10) matrix,a series of color-tunable emission can be achieved.Simultaneously,Tb3+and Eu3+can also affect the self-luminescent intensity of host slightly.Although there is no obvious energy transfer between host and activators,Tb3+has a distinct sensitive effect on Eu3+ascribed to the energy transfer between Tb3+and Eu3+.In addition,the thermal stability was carefully investigated,which demonstrate the materials can be as a candidate in fluorescent lamps and displays.     

Photoluminescence properties of dinuclear lanthanide complexes in visible and near-infrared region

Several dinuclear lanthanide complexes of Ln2(HTH)6TPPHZ (Ln=Eu, Sm, Er, Nd, Yb, Ho; TPPHZ=Tetrapyrido (3,2-a:2',3'-c:3',2"-h:2"',3'"-j) phenazine; HTH=4,5,5,6,6,6-heptafluroro-1-(2-thienyl)hexane-1,3-dione were synthesized and their photoluminescence properties were investigated. After ligand-mediated excitation, all the complexes showed the characteristic luminescence of the corresponding Ln(III) ions in the visible and NIR regions attributed to energy transfer from the ligands to the metal center. For Eu...     

Photoluminescence properties and thermal stability of Eu~(3+)-activated La_7Ta_3W_4O_(30) red-emitting phosphors for near-UV-excited w-LEDs

Novel trivalent europium(Eu~(3+))-activated La_7 Ta_3 W_4 O_(30):xEu~(3+)(x=0.5 mol%-40 mol%) red-emitting phosphors were synthesized by means of a high-temperature solid-state reaction.The structure,morphology,photoluminescence,thermal-stability properties,lifetime,and color-rendering of the prepared phosphors were investigated in detail.The La_7 Ta_3 W_4 O_(30):Eu~(3+) phosphors show five emission peaks under near-ultraviolet(n-UV) at 397 nm,and these peaks are ascribed to the transitions of ~5 D_0-~7 F_j(j=0,1,2,3 and 4) by Eu~(3+) ions.The optimal doping concentration of Eu~(3+) is 20 mol%,and the critical distance of the energy transfer between the Eu3+ions was calculated to be 1.768 nm.The quenching temperature(T_(0.5)) of La_7 Ta_3 W_4 O_(30):20 mol%Eu~(3+) is about 440 K.The quantum yield(QY) was measured to be 85.85%.The fabricated white-light-emitting diodes(w-LEDs) possess high color-rendering index(R_a) of 90,and high correlated color temperature(CCT) of 5810 K,respectively.The Commission Internationale de L'Eclairage(CIE) coordinates are(0.311,0.322).Therefore,the prepared phosphor has a promising application for w-LEDs.     

Use of Immobilized Bentonite in Removal of Heavy Metals from Wastewater

Bentonite is known to adsorb toxic metal ions from aqueous solutions. In this study bentonite was immobilized in a polymer matrix of polysulfone in the form of spherical beads to remove cadmium and copper ions. For this purpose a bead-producing unit was fabricated. The procedure for making beads is described. The beads exhibited a porous surface and surface area of up to 20 m2∕g. 99.4% of beads were retained on a sieve size of 1.18 mm and were finer than 2.36 mm. Batch adsorption data was adequately described by the Freundlich isotherm model. The beads were able to remove more than 99% of copper and cadmium ions in the column mode. These beads can find application as filter media in the removal of toxic heavy metal ions from aqueous solutions.     

Luminescent and thermometric properties of dual emitting Eu~(2+)/Sm~(3+) co-doped Sr_4La(PO_4)_3O phosphor based on energy transfer

Eu²⁺/Sm³⁺co-doped dual-emitting Sr₄La(PO₄)₃O phosphors were synthesized through a convenient high temperature solid state reaction in reductive atmosphere.The structure,luminescence,energy transfer and temperature-dependent luminescence properties of Eu²⁺/Sm³⁺co-doped Sr₄La(PO₄)₃O phosphors were researched and analyzed in detail.The blue emission of Eu²⁺and the red emission of Sm³⁺can work together as FIR signals.Based on the different response characteristics of these two ion emissions to temperature,Sr₄La(PO₄)₃O:Eu²⁺/Sm^(³⁺)phosphor achieves the relative sensitivity of0.48384%/K and a wide range of temperature measurements from room temperature to 573 K.The results reveal that the Sr₄La(PO₄)₃O:Eu²⁺/Sm³⁺phosphor has application prospect in the field of high temperature optical thermometry.The energy transfer mechanism is proved to be the dipole-dipole interaction between Eu²⁺and Sm³⁺ions.     

Effect of trivalent rare earth ions doping on the fluorescence properties of electron trapping materials SrS：Eu~（2＋）

Trivalent rare-earth ions (La3+,Pr3+,Nd3+,Sm3+,Gd3+,Tb3+,Dy3+,Ho3+,Er3+,Tm3+,and Yb3+) were investigated as the codoped auxiliary sensitizer for the electron trapping materials SrS:Eu2+ in order to enhance the fluorescence properties.It was found that Sm3+ and Tb3+ had the best photoluminescence stimulated luminescence (PSL) effect among the selected trivalent rare-earth ions.All the SrS:Eu2+ samples doped by different trivalent rare-earth ions could be stimulated by 980 nm laser after being exposed to the conventional sunlight,and they emitted PSL with the peak located at 615 nm.The result also indicated that some co-doped rare earth ions could increase fluorescence intensities of the traditional electron trapping materials SrS:Eu2+.     

Synthesis and characterization of CaAl_xO_y:Eu²⁺ phosphors prepared using solution-combustion method

Europium-doped calcium aluminate(CaAlxOy:Eu2+) phosphors were obtained at low temperatures(500 oC) by the solution-combustion of corresponding metal nitrate-urea solution mixtures.The particle size and morphology and the structural and luminescent properties of the as-synthesized phosphors were examined by means of scanning electron microscopy(SEM),X-ray diffraction(XRD),Auger spectroscopy,transmission electron spectroscopy(TEM) and photoluminescence(PL).It was found that the Ca:Al molar ratios showed greatly influence not only on the particle size and morphology,but also on their PL spectra and structure.With the Ca:Al molar ratios increasing from 6:100 to 26:100,the structure of as-synthesized phosphor changed from CaAl12O19 to monoclinic CaAl2O4 and the dominant emitting light from red to blue,implying that the oxidation state of doped europium ions changed from trivalent to divalent due to the structure variation of host lattice.A blue phosphor with almost pure phase can be easily prepared by solution combustion method with suitable Ca:Al molar ratio.     

Study on Anticoagulation Factor I from Agkistrodon Acutus Venom by Rare Earth Ion Probes

Ｓｎａｋｅｖｅｎｏｍｓｃｏｎｔａｉｎｃｏｍｐｌｅｘｐｒｏｔｅｉｎｓｗｈｉｃｈｐｏｓｓｅｓｓｖａｒｉｏｕｓｂｉｏｌｏｇｉｃａｌａｃｔｉｖｉｔｉｅｓ ,ｉｎ ｃｌｕｄｉｎｇａｃｌａｓｓｔｈａｔａｆｆｅｃｔｓｃｏａｇｕｌａｔｉｏｎｓｙｓｔｅｍｗｉｔｈｃｏａｇｕｌａｎｔｏｒａｎｔｉｃｏａｇｕｌａｎｔａｃｔｉｖｉｔｉｅｓ .Ａｎａｎｔｉｃｏａｇｕｌａｎｔｆａｃｔｏｒ (ＡＣＦ)ｗａｓｐｒｅｖｉｏｕｓｌｙｉｓｏ ｌａｔｅｄｆｒｏｍｔｈｅｖｅｎｏｍｏｆＡｇｋｉｓｔｒｏｄｏｎａｃｕｔｕｓｆｒｏｍｓｏｕｔｈｅｒｎＡｎｈｕ…     

石墨烯复合材料用于气敏传感器的研究进展

石墨烯(Graphene)自发现以来,凭借其出色的二维蜂窝的网状平面结构获得了良好的导电性、导热性,运用领域越来越广泛,也为各方面的科研提供了一系列创新思路。总结了石墨烯在气敏传感器领域的创新思路以及目前的发展概述和未来的展望。石墨烯独特的蜂窝网状结构对气体具有良好的吸附能力和在简单条件下的脱附能力,并且良好的导电能力使得待测气体在接触石墨烯表面时会发生电子交换改变石墨烯的电阻,而石墨烯为基的气敏传感材料正可以利用这个细小的变化来测量待测气体的浓度。为提高石墨烯的气敏特性,目前研究大多在石墨烯表面通过掺杂其他金属离子或者金属氧化物,以及有机高分子材料来提高石墨烯复合气敏材料的气敏特性。     

金属-有机框架材料ZIF-8的合成机理研究

金属-有机框架材料是将过渡金属离子与有机配体通过自组装而形成的网络状拓扑结构晶体,沸石咪唑酯框架材料是金属-有机框架材料的一个分支。本研究采用溶剂热法制备ZIF-8晶体,揭示主要影响因素对ZIF-8晶体形貌、大小的影响规律及合成过程机理,确定的最佳合成条件为:硝酸锌为锌源,2-甲基咪唑为有机配体,DMF为有机溶剂,金属离子与有机配体的摩尔比为3:2,合成温度为120℃,反应时间为10 h,并用X-射线衍射、扫描电子显微镜、红外光谱衍射、热重分析等对ZIF-8晶体表征。     

Luminescence properties of YAl3(BO3)4 phosphors doped with Eu3+ ions

YAl3(BO3)4: Eu3+ phosphors were prepared by the conventional solid state reaction. The phase structure and morphology were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). Doping YAl3(BO3)4: Eu3+ phosphors with concentration of Eu3+ ions of 0, 2, 5, 8 and 10 mol% were studied and their luminescent properties at room temperature were discussed. The excitation spectrum of Y0.95Eu0.05Al3(BO3)4 was composed of a broad band centered at about 252 nm and a group of lines in the longer wavelength re-gion. In the emission spectra, the peak wavelength was about 614 nm under a 252 nm UV excitation. The optimal doping concentration of Eu<3+ ions in YAl3(BO3)4: Eu3+ phosphors was 8 mol%.     

Influence of treatment with aminoglutethimide on plasma and red-blood-cell glutathione status in breast cancer patients

Using the method of differential scanning calorimetry, the DNA helix-coil transition was studied in solutions (10(-3) M Na+, 10(-3) M tris HCl, pH 7.0) containing divalent copper ions at relative metal ion concentrations (Mt2+/PDNA) ranging from 0.2 to 20. Dependences of the melting temperature and enthalpy on relative ion concentration were determined. An aggregation of Cu(2+) + DNA complexes in the range of average ion concentration was established. It is shown that the melting enthalpy of "units" increases with copper ion concentration. The data obtained were compared with values determined by UV-spectroscopy. Association constants for Cu2+ binding to DNA were defined by the ligand theory.     

Solvent extraction-separation of La(III), Eu(III) and Er(III) ions from aqueous chloride medium using carbamoyl-carboxylic acid extractants

N,N-dibutyldiglycol amic acid(HLI) and N,N-dioctyldiglycol amic acid(HLII) were synthesized and characterized by conventional spectroscopic methods. These molecules were examined as extractants for extraction-separation of La(III), Eu(III) and Er(III), as representative ions of light, middle and heavy rare earths, from aqueous chloride solutions. The analysis of the extraction equilibria revealed that the extracted species of lanthanum and europium ions by both of the extractants had a 1:3 metal to ligand ratio. It was suggested that erbium ions were extracted into the organic phase via the formation of Er(LI or II)2Cl complexes. The effect of the organic diluents on the extraction-separation efficiency of the studied rare earths by HLI and HLII was investigated by comparing the results obtained in dichloromethane and carbon tetrachloride. Regardless to the diluent used, the order of selectivity presented by the investigated extractants was Er(III)Eu(III)La(III). It is noteworthy that, a significant enhancement in separation of the studied rare earths by the extractants was achieved in their competitive extraction experiments with respect to that obtained in single component extraction experiments. Applicability of the extractants for the removal of rare earth ions from spent Ni-MH batteries was tested by removal of La(III), Eu(III) and Er(III) ions from simulated leach solution of such batteries.     

Energy transfer from Tb³⁺ to Eu³⁺ in zinc lead borate glass

In order to sensitize the luminescence of Eu3+ ions in heavy metal glass,zinc lead borate glass samples containing various concentrations of Eu3+ and Tb3+ ions were prepared to study the Tb3+ to Eu3+ non-radiative energy transfer phenomena.Energy level structures of Tb3+ and Eu3+ ions were plotted to show the excitation and energy transfer routes.Efficient energy transfer from Tb3+ to Eu3+ was observed and studied qualitatively in terms of doping concentrations.The sensitization turned out to be less effective than expected.Further studies to characterize the oxidation of Tb3+ into tetravalent state and to examine the mechanism of energy transfer are proposed.     

Synthesis, Characterization and Fluorescence of Phenylcarboxymethyl Sulfoxide Complexes with Lanthanide Nitrates

Ｒａｒｅｅａｒｔｈｃｏｍｐｌｅｘｅｓｗｉｔｈｓｕｌｆｏｘｉｄｅａｎｄａｒｏｍａｔｉｃｃａｒｂｏｘｙｌａｃｉｄｈａｖｅｂｅｅｎｗｉｄｅｌｙｓｔｕｄ ｉｅｄ[1～ 3 ] .Ｉｔｉｓｐｒｏｖｅｄｔｈａｔｔｈｅｙｂｏｔｈｈａｖｅｂｅｔ ｔｅｒｆｌｕｏｒｅｓｃｅｎｃｅｃｈａｒａｃｔｅｒ .Ｈｏｗｅｖｅｒｔｈｅａｒｏ ｍａｔｉｃｃａｒｂｏｘｙｌｏｆｒａｒｅｅａｒｔｈｃｏｍｐｌｅｘｅｓｈａｖｅｖｅｒｙｈｉｇｈｆｌｕｏｒｅｓｃｅｎｃｅｅｍｉｓｓｉｏｎｉｎｔｅｎｓｉｔｙａｎｄｓｔａｂｉｌｉｔｙ ,ｂｕｔｓｏｌｕｂｉｌｉｔｙｉ…     

Luminescence of Eu(MBA)_2NO_3Phen Complexes

ＬｕｍｉｎｅｓｃｅｎｃｅｏｆＥｕ（ＭＢＡ）_２ＮＯ_３ＰｈｅｎＣｏｍｐｌｅｘｅｓＪｉｎＬｉｎ－ｐｅｉ（金林培）；ＴｏｎｇＪｉｎ－Ｑｉａｎｇ（童金强）；ＷａｎｇＭｉｎｇ－Ｚｈａｏ（王明昭）；（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＢｅｉｊｉｎｇＮｏ...     

Photoluminescence properties of LaF3：Eu^3＋ nanoparticles prepared by refluxing method

The europium-doped LaF3 nanoparticles were prepared by refluxing method in glycerol/water mixture and characterized with X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), UV-vis diffuse reflectance spectrum, and photoluminescence spectra. The results of XRD indicated that the obtained LaF3: Eu3+ nanoparticles were well crystallized with a hexagonal structure. The FE-SEM image illustrated that the LaF3: Eu3+ nanoparticles were spherical with an average size around 30 nm. Under irradiation of UV light, the emission spectrum of LaF3: Eu3+ nanoparticles exhibited the characteristic line emissions arising from the 5D0→7FJ (J=1, 2, 3, 4) transitions of the Eu3+ ions, with the dominating emission centered at 590 nm. In addition, the emissions from the 5D1 level could be clearly observed due to the low phonon energies (-350 cm-1) of LaF3 matrix. The optimum doping concentration for LaF3: Eu3+ nanoparticles was determined to be 20mol.%.