Preparation and catalytic performance of Fe-SBA-15 and FeO x /SBA-15 for toluene combustion

High-surface-area and well-ordered mesopor- ous Fe-incorporated SBA-15 （xFe-SBA-15） and SBA-15- supported FeOx （yFeOx/SBA-15） with the Fe surface den- sity between 0.09 to 1.11 Fe-atom/nm2 have been prepared using the one-step synthesis and incipient wetness impregnation methods, respectively. Physicochemical properties of these materials were characterized by means of numerous techniques, and their catalytic activities for the combustion of toluene were evaluated. It is found that the xFe-SBA-15 and yFeOx/SBA-15 samples possessed rod- or chain-like morphologies. The Fe species were of high dispersion when the Fe surface density was lower than 0.76 Fe-atom/nm2 in xFe-SBA-15 and 0.64 Fe-atom/nm2 in yFeOx/SBA-15. At a similar Fe surface density and space velocity, the xFe-SBA-15 catalysts showed better activity than the yFeOJSBA-15 catalysts, in which the xFe-SBA- 15 catalyst with Fe surface density 0.59 Fe-atom/nm2 performed the best. It is concluded that the good perfor- mance of the xFe-SBA-15 sample with Fe surface density 0.59 Fe-atom/nm2 was associated with its large surface area, high Fe species dispersion, and good low-temperature reducibility.     

介孔分子筛SBA-15的功能化改性及酶固定化研究

介孔材料具有均匀可调的孔道、较大的孔容和很大的比表面积,是固定化酶的重要载体。其中,介孔分子筛SBA-15上含有大量具有化学活性的自由硅羟基,可以通过化学修饰引入功能化基团来改善SBA-15的表面微环境及其与生物酶分子的亲合作用,实现生物酶和载体材料的共价结合,进而提高固定化生物酶的催化活性,具有很高的实用价值,得到了长足发展。此文综述了近年来介孔分子筛SBA-15的功能化改性及其酶固定化的研究进展,着重介绍了-NH2和-COOH功能化SBA-15在固定化生物酶上的研究现状,并展望了其发展前景。     

SnO_2-SBA-15介孔分子筛的制备与表征

首先以P123、正硅酸乙酯为原料合成了SBA-15介孔分子筛,然后利用氯化亚锡的水解反应在SBA-15介孔分子筛表面及孔道内部沉积纳米SnO_2,对其进一步功能化,成功制备出了SnO_2-SBA-15介孔分子筛.采用多晶X射线衍射(XRD)、傅里叶变换红外光谱分析、同步热分析、氮气吸脱附等技术手段对材料的结构组成进行了表征,结果表明纳米二氧化锡成功负载到了SBA-15介孔分子筛表面和孔道内部.     

Crystalline mesoporous metal oxide

Since the discovery of many types of mesoporous silicas, such as SBA-15, KIT-6, FDU-12 and SBA-16, porous crystalline transition metal oxides, such as Cr2O3, Co3O4, In2O3, NiO, CeO2, WO3, Fe2O3 and MnO2, have been synthesized using the mesoporous silicas as hard templates. Several synthetic methods have been developed. These new porous materials have high potential applications in catalysis, Li-ion rechargeable batteries and gas sensors. This article gives a brief review of the research of porous crystals of metal oxides in the last four years.     

WO3-ZrO2/SBA-15的制备及其可见光催化分析

通过溶胶凝胶法,分别制备了不同负载量的WO_3/SBA-15和WO_3-ZrO_2/SBA-15介孔材料,利用XRD、BET和TEM等表征手段对其进行表征,并对其光降解染料罗丹明B的活性进行比对研究分析。结果表明:Wx/SBA-15(x=20,30,40,50)和W_(40)Zry/SBA-15(y=3,5,7,9)均能在可见光下光降解罗丹明B,光催化活性W_(40)/SBA-15W_(50)/SBA-15W_(30)/SBA-15W_(20)/SBA-15;引入ZrO_2后,光催化活性W_(40)Zr_5/SBA-15W_(40)Zr_9/SBA-15W_(40)Zr_7/SBA-15W_(40)Zr_3/SBA-15。其中,W_(40)/SBA-15和W_(40)Zr_5/SBA-15的光降解效率最高,分别为73.4%和86.6%,ZrO_2的引入提高了光降解效率;同时,WO_3/SBA-15和WO_3-ZrO_2/SBA-15也具有很好的循环价值,可多次使用。     

Fabrication of copper nanorods by low-temperature metal organic chemical vapor deposition

Copper nanorods have been synthe-sized in mesoporous SBA-15 by a low-temperature metal organic chemical vapor deposition (MOCVD) employing copper (II) acetylacetonate, Cu(acac)2, and hydrogen as a precursor and reactant gas, re- spectively. The hydrogen plays an important role in chemical reduction of oganometallic precursor which enhances mass transfer in the interior of the SBA-15 porous substrate. Such copper nanostructures are of great potentials in the semiconductor due to their unusual optical, magnetic and electronic properties. In addition, it has been found that chemically modi- fying the substrate surface by carbon deposition is crucial to such synthesis of copper nanostructures in the interior of the SBA-15, which is able to change the surface properties of SBA-15 from hydrophilic to hydrophobic to promote the adsorption of organic cupric precursor. It has also been found that the copper nanoparticles deposited on the external sur- face are almost eliminated and the copper nanorods are more distinct while the product was treated with ammonia. This approach could be achieved under a mild condition: a low temperature (400℃) and vac-uum (2 kPa) which is extremely milder than the con- ventional method. It actually sounds as a foundation which is the first time to synthesize a copper nanorod at a mild condition of a low reaction temperature and pressure.     

Preparation and characterization of a novel composite microporous polymer electrolyte for Li-ion batteries

A novel composite microporous polymer electrolyte composed of poly（vinylidene fluoride-co-hexafluoropropylene） （PVdF-HFP） and mesoporous SBA-15 was prepared. The composite solid polymer electrolyte （CSPE） exhibits ionic conductivity as high as 0.30 mS·cm^-1 with a composition of SBA-15 ： PVdF-HFP=3 ： 8 at room temperature. Infrared transmission spectroscopic results suggested that the mechanism of micropore formation is similar to that of the phase inversion. X-ray diffraction （XRD） results demonstrated that the addition of SBA-15 inhibits the crystallization of PVdF-HFP, while the SBA-15 preserves well its ordered mesoporous structure during the course of preparation. The Li/CSPE/MCF of half-cell was assembled, and it showed a good electrochemical and cyclability performance during charge-discharge cycles.     

铁掺杂TiO_2-SBA-15催化剂制备及光催化降解甲基橙研究

采用溶胶-凝胶法,将TiO_2负载到介孔分子筛SBA-15上,再通过FeCl3浸渍的方法,将不同量的铁掺杂到TiO_2-SBA-15上.通过FT-IR、XRD、N2吸附-脱附和TEM等手段对铁掺杂TiO_2-SBA-15催化剂进行表征.结果表明:负载TiO_2后的SBA-15依然为高度有序的二维六方结构,比表面积略有减小,说明SBA-15的孔道结构有利于TiO_2的分散.掺铁后的TiO_2-SBA-15的结构改变不大,且TiO_2晶形仍为锐钛矿型.最后以光催化降解甲基橙探究不同铁掺杂量的TiO_2-SBA-15催化活性.结果表明:铁离子掺杂量为0.035%(质量分数),紫外光照射200min时,甲基橙降解率达最高值98.2%.     

新型介孔钒氧化物催化剂上丙烷高选择性氧化脱氢制丙烯研究

采用醇溶液浸渍法制备了介孔SBA-15、介孔MCM-41及无定形SiO2三种不同氧化硅载体担载的系列钒氧化物催化剂．活性测试结果表明,SBA-15为载体的钒氧化物催化剂具有优良的丙烷氧化脱氢反应性能．BET、SEM/TEM、UV-Vis DRS,TPR,UV Raman和程序升温吡啶-FTIR结果表明：介孔SBA-15载体较大的比表面积及孔径、对钒氧物种较高的分散能力以及催化剂表面仅存在少量的弱酸性位等特点有利于丙烷的活化及产物丙烯的脱附,使得催化剂在丙烷氧化脱氢反应中显示出高活性和高选择性．     

On-line catalytic upgrading of biomass fast pyrolysis products

Pyrolysis-gas chromatography/mass spectrometry （Py-GC/MS） was employed to achieve fast pyrolysis of biomass and on-line analysis of the pyrolysis vapors. Four biomass materials （poplar wood, fir wood, cotton straw and rice husk） were pyrolyzed to reveal the difference among their products. Moreover, catalytic cracking of the pyrolysis vapors from cotton straw was performed by using five catalysts, including two microporous zeolites （HZSM-5 and HY） and three mesoporous catalysts （ZrO2＆TiO2, SBA-15 and AI/SBA-15）. The results showed that the distribution of the pyrolytic products from the four materials differed a little from each other, while catalytic cracking could significantly alter the pyrolytic products. Those important primary pyrolytic products such as levoglucosan, hydroxyacetaldehyde and 1-hydroxy-2-propanone were decreased greatly after catalysis. The two microporous zeolites were ef- fective to generate high yields of hydrocarbons, while the three mesoporous materials favored the formation of furan, furfural and other furan compounds, as well as acetic acid.     

磷酸化处理对蚕蛹多肽结合钙能力的影响

为探索磷酸化处理对多肽结合钙能力的促进作用,以蚕蛹多肽为研究对象,采用不同种类和添加量的磷酸化试剂对其进行磷酸化改性,再与CaCl₂反应制备蚕蛹多肽结合钙复合物,并对样品进行钙和磷含量测定、磷酸化位点检测、红外光谱分析和扫描电镜分析。研究结果表明:Na₃PO₄、NaH₂PO4、(NaPO₃)₆ 3种试剂可与蚕蛹多肽发生磷酸化反应,改性后蚕蛹多肽结合钙含量可从145.12mg/g提高至202.32mg/g ;不同种类磷酸化试剂处理对多肽的结合钙能力无显著性差异,但磷酸化程度对肽结合钙能力有较大影响;多肽结合钙复合物中钙含量随磷酸化试剂的增加先升高后下降,当采用质量分数为0.50%的NaH₂PO₄时,改性后蚕蛹多肽结合钙含量达到最大值。红外光谱和磷酸化位点检测表明:NaH₂PO₄处理可使蚕蛹酶解产物中的17种肽段被磷酸化,增加磷酸化位点22个;肽段主要通过与丝氨酸和苏氨酸上的—OH反应接入磷酸基团。研究表明,磷酸化改性方法可显著提高多肽结合钙能力,希望为高效的补钙制品开发提供新的思路和方法。     

磁性FeNi合金/石墨化介孔碳纳米复合材料的合成及其在染料吸附中的应用

以介孔SBA-15为模板,金属硝酸盐作为磁性FeNi合金纳米颗粒前驱物,采用纳米铸造法合成出一系列磁性FeNi合金/石墨化介孔碳纳米复合材料.利用X射线衍射仪(XRD)、N₂吸附-脱附仪(BET)、电感耦合等离子体质谱仪、透射电子显微镜(TEM)、振动样品磁强计(VSM)和热重分析仪(TG)等对合成物进行表征.结果发现,试验得到的纳米复合材料具有一致的介孔结构,高含量的磁性FeNi合金纳米晶体(尺寸大约是3~6 nm)均匀分散在石墨介孔碳模型的壁上,此介孔材料具有高的比表面积(360.3~431.9 m²·g^-1),大孔体积(0.558~0.718 cm³·g^-1)和高饱和磁化强度(18.2~42.1 emu·g^-1).基于以上特性,研究了材料对于水中染料的吸附性能.结果发现,当染料浓度为50 mg·L^-1时,材料对其去除率接近100%,同时在外加磁场存在时,悬浮液可以很好地实现固液分离.因此,磁性FeNi合金/石墨化介孔碳纳米复合材料在去除废水中的染料方面可以作为高效和可循环使用的吸附剂.     

Antilocalization sensing of interactions between two-dimensional electrons and surface species

We apply antilocalization measurements to experimentally study the interactions and exchange between InAs surface accumulation electrons and local magnetic moments of the rare earth ions Sm3?,Gd3?,Ho3?,and Dy3?,of the transition metal ions Ni2?,Co2?,and Fe3?,and of Fe3O4nanoparticles and Fe3?-phthalocyanine deposited on the surface.The influence of the deposited species on the surface electrons is observed through the changes in the spin–orbit scattering and magnetic spin-flip scattering rates,which carry information about magnetic interactions.Experiments indicate a temperature-dependent magnetic spin-flip scattering for Ho3?,Dy3?,Ni2?,and Co2?.Concerning the spin–orbit scattering rate,we observe an increase,except for the cases of Ni2?,Fe3?,Fe3O4nanoparticles and Fe3?-phthalocyanine.We also observe an increase in SO scattering in another system where we study the interactions of Au nanoparticles and ferromagnetic Co0.6Fe0.4nanopillars and an In0.53Ga0.47As quantum well.Experimental results are analyzed and compared to theoretical models.Our method provides a controlled way to probe the quantum properties of two-dimensional electron systems,either on the surface of InAs or in a quantum well.     

李政, 宋益善, 左思语,刘超,马晨晨

氨基酸分子首次用以制备构筑稀土介孔发光材料.L-丝氨酸通过分子修饰得到新配体2-烟酰氨基-3-羟基丙酸(L),并进一步引入MCM-41介孔基质中,最后和稀土Tb3+离子复合得发光介孔材料Tb-L-MCM-41.通过核磁共振、紫外、XRD、氮吸附和荧光光谱等对配体和杂化材料的结构和性质进行了表征.结果表明,配体L很好的引入到MCM-41介孔基质中,Tb-L-MCM-41介孔材料呈现L的特征紫外吸收.同时,稀土配合物的引入占据了MCM41基质的部分孔道,使其比表面和孔体积都有所降度.Tb-L-MCM-41呈现稀土Tb3+离子的特征光.     

SBA-15基功能材料吸附应用研究进展

介孔SBA-15分子筛因具有较大的孔径、较高的比表面积和较厚的孔壁,在催化、吸附、分离、药物控释以及化学传感等领域得到广泛的应用。介绍了介孔分子筛的发展过程,并着重就SBA-15基功能材料在吸附应用方面的研究状况进行概述,最后展望了SBA-15功能材料未来的发展方向与应用前景。     

Synthesis of mesoporous polymeric carbon nitride exhibiting enhanced and durable visible light photocatalytic performance

A thiourea precursor was employed to synthesize mesoporous carbon nitride(C3 N4) by a thermal polycondensation process with high surface area SiO2 and nanosphere SiO2 as two types of hard templates. The resultant mesoporous C3 N4 samples have high surface areas(105–112 m2/g) and mesopores with narrow sizes distribution(9.3 nm). Photocatalytic performance was evaluated by removal of NO in air under visible light irradiation. The results showed that mesoporous C3 N4 samples exhibited significantly improved photocatalytic activity in comparison with bulk C3 N4, which also exceeded that of N-doped TiO2 and C-doped TiO2. The activity enhancement can be ascribed to the synergistic effects of large surface area and pore volume, enhanced light-harvesting ability, increased redox potential, and reduced recombination of charge carriers. In addition to the high activity, the mesoporous C3 N4 samples also showed high photochemical stability. The mesoporous C3 N4 photocatalysts with enhanced and durable activity could provide a new efficient material for environmental pollution control.     

Grafting of thermoresponsive polymer from the surfaceof functionalized multiwalled carbon nanotubes via atom transfer radical polymerization

Multiwalled carbon nanotubes were oxidized with concentrated HNO3 and H2SO4 to introduce carboxylic groups onto carbon nanotubes surfaces. The oxidized carbon nanotubes were reacted subsequently with thionyl chloride and 2-Hydroxylethyl-2＇-bromoisobutyrate, producing MWNT-based macroinitiators, MWNT-Br, for the atom transfer radical polymerization of （N-isopropylacrylamide）. FTIR, XPS, ^1H NMR, Raman and TGA were used to characterize the resulting products and to determine the content of the water-soluble poly （N-isopropylacrylamide） chains in the product. The MWNTs grafted with PNIPAM chains have good solubility in distilled water; THF and CHCl3. TEM images of the samples provide direct evidence for the formation of a nanostructure that MWNTs coated with polymer layer. The produced MWNT-g-PNIPAM has a PNIPAM shell, which is very sensitive to the change of temperature. This method would open a door for the fabrication of novel functional carbon nanotube-based nanomaterials or nanodevices with designable structure and tailor-made properties.     

Solution chemistry of carbonate minerals and its effects on the flotation of hematite with sodium oleate

The effects of carbonate minerals (dolomite and siderite) on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared (FTIR) spectroscopic studies, and X-ray photoelectron spectroscopy (XPS) analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations (Ca2+ and Mg2+) and CO₃2- ions dissolved from dolomite depressed hematite flotation, whereas only the CO₃2- ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca2+, Mg2+, and CO₃2- (HCO₃-) could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.     

化肥厂高浓度氨氮废水的处理和回用

在实验室规模研究了通过生成鸟粪石（磷酸铵镁, MAP）去除氨氮工艺条件的影响. 加入磷酸和MgO产生MAP沉淀, pH值对其影响很大, pH值为9.0时氨氮去除效果最好. PO₄^3-, Mg²⁺, NH₄⁺的摩尔比为1 ∶1.5 ∶1时, 氨氮去除率较大并且可较好地回收氨生成鸟粪石. 此外, 物料的加入次序严重影响氨氮的去除. 两步沉淀工艺氨氮去除率达99.1%, 氨回收率为80.1%.     

碳纳米管表面的氨基化修饰及其聚脲基纳米复合材料的制备和力学性能研究

设计了一种碳纳米管表面氨基化修饰及其聚脲基纳米复合材料的分子设计和制备方法。首先，通过混酸氧化处理得到羟基化碳纳米管；其次，以原位聚合法，通过聚丙烯酸中羧基和碳纳米管表面羟基的酯化反应，将聚丙烯酸接枝到碳纳米管表面；最后，通过接枝聚丙烯酸和端氨基聚醚D-400的酰胺化反应，在碳纳米管表面实现氨基官能化修饰。将氨基修饰的碳纳米管均匀分散在端氨基聚醚固化剂混合物中，进而与端异氰酸根预聚物组分反应得到碳纳米管/聚脲基纳米复合材料。经测试可知，氨基化碳纳米管质量分数为0.7%时，在聚脲基体中分散比较均匀，且聚脲的拉伸强度比原始碳纳米管修饰的聚脲增加了40%。