ZnFe_2O_4/ZnO气相法催化合成烷基吡嗪

改进的柠檬酸络合法制备了ZnFe2O4/ZnO催化剂,并用于乙二胺和2,3-丁二醇环化脱氢制备烷基吡嗪。用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)对催化剂进行了表征。考察了Zn/Fe摩尔比、反应温度、载气空速对2,3-丁二醇转化率和烷基吡嗪选择性的影响。结果表明,在n(Zn)∶n(Fe)=2∶1、反应温度380℃、原料液流速0.02 mL/min、载气空速1 440 h-1时,2,3-丁二醇的转化率为93.38%,烷基吡嗪的收率为85.47%,其中,2,3-二甲基吡嗪的收率为22.16%、2-甲基吡嗪的收率为63.31%。     

管状TiO2/层状ZnFe2O4复合材料的制备及其可见光催化性能

采用溶剂热-共沉淀两步法制备了管状TiO2/层状ZnFe2O4复合材料,采用X射线衍射(XRD)、透射电镜(TEM)和振动样品磁强计(VSM)等对其晶体结构、微观形貌和磁性能等进行表征,并以罗丹明B(RhB)和亚甲基蓝(MB)为目标降解物测试了样品的光催化性能.结果表明:TiO2为介孔中空管状结构,ZnFe2O4为疏松...     

模板剂-水热法合成纳米ZnFe2O4-TiO2光催化剂

研究了以多孔陶粒浮球为载体,采用模板剂-水热法制备了纳米ZnFe2O4／TiO2复合光催化剂膜。主要研究了ZnFe2O4的掺杂对TiO2晶相结构、烧结温度、吸光性能及其光催化活性的影响和模板剂PEO20PPO70PEO20即P123的添加对ZnFe2O4／TiO2复合光催化剂膜性能的影响。采用XRD、UV—Vis吸光光谱、SEM和EDS等对ZnFe2O4／TiO2复合光催化剂膜的性能进行了表征。研究结果表明,适量掺杂ZnFe2O4,可以使TiO2成为催化活性较好的锐钛矿相;适量的添加模板剂P123可以提高TiO2的比表面积,P123与TiO2的摩尔比为0．02：1时催化效果最好,这时ZnFe2O4/TiO2光催化剂对甲基橙脱色率在40min时可以达剑80％以上。     

催化氨氧化2-甲基吡嗪合成2-氰基吡嗪的研究

实验采用自制的Sb2O3-V2O5-TiO2/SiO2型催化剂,研究了以2-甲基吡嗪为原料氨氧化催化合成2-氰基吡嗪的工艺条件,通过对反应温度、液时空速、氨气流率、空气流率等影响因素的考察,确定了适合该催化剂的工艺条件:催化剂装量19mL,进料液时空速0.79h-1,n(2-MP)∶n(NH3)∶n(Air)为1∶5.9∶36,温度370°C。2-甲基吡嗪的转化率达到90%以上,选择性达到70%以上,产品收率达到60%以上。并对其反应原理及工业化问题进行了初步的探讨。     

氨氧化催化合成氰基吡嗪的研究

研究2-甲基吡嗪氨氧化催化合成2-氰基吡嗪的催化反应机理后,可知2-甲基吡嗪是通过一系列的脱氢、氧化生成甲醛吡嗪和羧酸吡嗪然后氰化生成产物的,因此优良的催化剂必须由活性及数目合适的脱氢、供[O]及氰化中心组成.分析了各种氨氧化催化剂后,研制了Sb2O3-V2O5-TiO2/SiO2型催化剂,通过实验分别考察反应温度,进料空速,原料配比的影响.确认在空速0.3h-1,反应温度380℃,配料比为2-甲基吡嗪：氧气：氨气=1：8.5：3（摩尔比）时,2-甲基吡嗪的转化率为70%以上,2-氰基吡嗪的收率为55%以上.与同类催化剂相比,具有反应温度低,空速大等优点,更适合工业化;同时也验证了催化反应机理的合理性.     

玻璃基片上ZnFe2O4薄膜光催化降解性能的研究

采用旋转镀膜法在玻璃表面制备了ZnFe2O4薄膜，通过改变ZnFe2O4的浓度、烧成温度及薄膜层数，研究了ZnFe2O4薄膜的均匀性及对甲基橙的光催化降解性能。结果表明，ZnFe2O4薄膜均匀性好，对甲基橙有较高的分解效果。     

中空ZnFe2O4微球的合成及其电化学性能

以Zn(Ac)2×4H2O和FeCl3×6H2O为主要原料,采用一步水热法合成了中空结构的ZnFe2O4微球,对其物相、形貌和组成进行了分析. 结果表明,中空ZnFe2O4粒径微球约300 nm,壳厚约25 nm. 以其为锂离子电池负极材料,100 mA/g电流密度下,首次放电容量为1524 mA×h/g, 50次充放电循环后容量约为826 mA×h/g,呈现出优异的循环性能.     

5-甲基吡嗪-2-羧酸的合成

以异丙醇胺为原料,经环合制得2,5-二甲基吡嗪,再以醋酸钴、醋酸锰作催化剂,溴化钾作助催化剂下催化氧化制得标题化合物,总收率68％.     

吡嗪-2,3-二羧酸的合成新工艺

介绍了以二氨基马来腈和乙二醛为原料,经环化合成2,3-二氰基吡嗪,再经水解生成吡嗪-2,3-二羧酸的反应过程,全程反应条件温和,产品总收率高于65%。     

ZnFe2O4高温煤气脱硫剂的再生

在热天平上对自制的ZnFe2O4脱硫剂进行了再生工艺研究，考察了再生温度、O2浓度对ZnFe2O4脱硫剂再生性能的影响；进行了多次硫化、再生循环实验，并与加入玻璃粉的样品进行了比较。结果表明，700℃下氧含量2.0%(vol)时再生可以获得良好的再生率和二次硫化反应活性；玻璃粉的少量加入，会改善脱硫剂长期使用的稳定性，但反应活性有所下降。     

影响纳米ZnFe2O4光电催化用薄膜的因素

本文采用sol-gel法在导电玻璃上制备了纳米铁酸锌薄膜光催化剂,用差热膨胀仪对干凝胶粉的加热过程进行了分析,采用XRD、SEM等手段对制备薄膜的结构性能进行表征.结果表明：制备的纳米铁酸锌薄膜颗粒粒度均匀,平均粒径为40 nm左右.     

纳米锌铁氧体研究现状及发展前景

简要介绍了纳米锌铁氧体（ZnFe2O4）的研究现状。详细分析了目前国内外纳米锌铁氧体的主要制备方法及研究进展,比较了各种制备方法的优缺点。结合相关行业的发展,指出纳米锌铁氧体今后的研究方向及发展前景。     

玻璃表面上掺杂ZnFe2O4的TiO2薄膜光催化性能的研究

采用溶胶－凝胶法在玻璃表面制备了掺杂ZnFe2O4的TiO2薄膜，通过改变ZnFe2O4的掺杂量和薄膜的热处理温度，研究了ZnFe2O4对TiO2薄膜光催化性能的影响。利用紫外光谱、SEM、XRD等测试手段指出了在TiO2薄膜中掺杂ZnFe2O4后，能较大幅度地提高TiO2薄膜的光催化活性。     

Preparation,structural, and electrical studies of polyaniline/ZnFe2O4 nanocomposites

Polyaniline/ZnFe₂O₄ nanocomposites were synthesized by a simple and inexpensive one‐step in situ polymerization method in the presence of ZnFe₂O₄ nanoparticles. The structural, morphological, and electrical properties of the samples were characterized by wide angle X‐ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). WAXD and SEM revealed the formation of polyaniline/ZnFe₂O₄ nanocomposites. Infrared spectroscopy indicated that there was some interaction between the ZnFe₂O₄ nanoparticles and polyaniline. The dc electrical conductivity measurements were carried in the temperature range of 80 to 300 K. With increase in the doping concentration of ZnFe₂O₄, the conductivity of the nanocomposites found to be decreasing from 5.15 to 0.92 Scm⁻¹ and the temperature dependent resistivity follows ln ρ(T) ∼ T^−1/2 behavior. The nanocomposites (80 wt % of ZnFe₂O₄) show a more negative magnetoresistance compared with that of pure polyaniline (PANI). These results suggest that the interaction between the polymer matrix PANI and zinc nanoparticles take place in these nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

纳米固体超强酸SO2-4/CoFe2O4催化合成棕榈酸异辛酯的研究

利用硝酸铁和硝酸钴为原料制备了纳米固体超强酸SO24-/CoFe2O4催化剂.透射电镜(TEM)测最结果表明,自制催化剂颗粒粒径在20～50 nm.实验探讨了硫酸铵浸渍浓度、催化剂焙烧温度、焙烧时间对催化剂催化活性的影响;并以纳米固体超强酸SO2-4/CoFe2O4为催化剂,研究了棕榈酸与异辛醇合成棕榈酸异辛酯过程中影响酯化率的主要因素.实验确定的最优合成条件是:醇酸物质的量比2.0:1,催化剂质量分数(占反应物总质量的分数)0.50%,反应时间3.0 h,并添加了带水剂,在此条件下反应的酯化率可达97.4%.     

Fabrication and photocatalytic properties of novel ZnO/ZnAl2O4 nanocomposite with ZnAl2O4 dispersed inside ZnO network

Novel ZnO/ZnAl₂O₄ nanocomposites with ZnAl₂O₄ nanoparticles homogeneously dispersed inside a network of ZnO are fabricated by thermal treatment of a single‐source precursor of ZnAl‐layered double hydroxides (ZnAl‐LDHs) at 800°C. The effects of the Zn/Al molar ratio of the LDH precursors on the structure, composition, morphology, textural as well as UV‐absorbing properties and photocatalytic activities of the nanocomposites are investigated in detail. The results show that the ZnO/ZnAl₂O₄ nanocomposites derived from the ZnAl‐LDHs precursors have superior photocatalytic performances to either single phase ZnO or similar ZnO/ZnAl₂O₄ samples fabricated by chemical coprecipitation or physical mixing method. The heterojunction nanostructure and the strong coupling between the ZnO and ZnAl₂O₄ phase derived from ZnAl‐LDHs precursors are proposed to contribute the efficient spatial separation between the photo‐generated electrons and holes, which can concomitantly improve the photocatalytic activities. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

软模板水热法制备空心ZnFe2O4及吸波性能

以六水合氯化铁和氯化锌为原料,聚乙二醇4000为表面活性剂,采用软模板水热法一步合成了具有空心结构的ZnFe2O4纳米颗粒。采用XRD、XPS、FE-SEM和TEM对样品的物相和形貌进行了表征,通过振动样品磁强计（VSM）和矢量网络分析仪测试了样品的静磁性能和电磁参数,并模拟计算了样品的反射损耗,考察了其吸波性能。结果表明：所制备的ZnFe2O4粒径约为100 nm,分散均匀,具有明显的空心结构。吸波性能优异。当样品的匹配厚度为2.7 mm时,在12.41GHz处获得最小的反射损耗（-42.18dB）;而当匹配厚度为3.0mm时,样品的有效吸收带宽（反射损耗≤-10dB,即吸收率为90%）最宽,为2.60GHz（10.60~13.20GHz）。     

Synthesis of hierarchical dendritic micro–nano structure ZnFe_2O_4 and photocatalytic activities for water splitting

Hierarchical dendritic micro–nano structure Zn Fe_2O_4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electron microscopy were used to characterize the crystal structure, size and morphology. The results show that the sample(S-2) is composed of pure ZnFe_2O_4 when the molar ratio of Zn~(2+)/Fe~(2+)in the electrolyte is 0.35. Decreasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-1) is composed of ZnFe_2O_4 and α-Fe_2O_3, whereas increasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-3) is composed of ZnFe_2O_4 and Zn O. The lattice parameters of ZnFe_2O_4 are influenced by the molar ratio of Zn~(2+)/Fe: Zn at excess decreases the cell volume whereas Fe at excess increases the cell volume of Zn Fe_2O_4. All the samples have the dendritic structure, of which S-2 has micron-sized lush branches with nano-sized leaves. UV–Vis diffuse reflectance spectra were acquired by a spectrophotometer. The absorption edges gradually blue shift with the increase of the molar ratio of Zn~(2+)/Fe~(2+). Photocatalytic activities for water splitting were investigated under Xe light irradiation in an aqueous olution containing 0.1 mol·L~(-1)Na_2S/0.02 mol·L~(-1)Na_2SO_3 in a glass reactor. The relatively highest photocatalytic activity with 1.41 μmol·h-1· 0.02 g~(-1)was achieved by pure ZnFe_2O_4sample(S-2). The photocatalytic activity of the mixture phase of Zn Fe_2O_4 and α-Fe_2O_3(S-1) is better than ZnF e_2O_4 and ZnO(S-3).