Tunable Synthesis of Core-shell α-Fe2O3/TiO2 Composite Nanoparticles and Their Visible-light Photocatalytic Activity

Uniform α-Fe₂O₃/amorphous TiO₂ core-shell nanocomposites were prepared via a hydrolysis method and α-Fe₂O₃/anatase TiO₂ core-shell nanocomposites were obtained via a post-calcination process. The structure and morphology of the products were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and scanning electron microscopy. Amorphous TiO₂ nanoparticles with diameters of ten to several tens nanometer were formed on the surface of α-Fe₂O₃ nanoparticles and the coverage density of the secondary TiO₂ nanoparticles in the composite can be controlled by varying the concentration of Ti(BuO)₄ in the ethanol solution. The visible-light photocatalytic properties of different products towards Rhodamine B(RhB) were investigated. The results show that the α-Fe₂O₃/amorphous TiO₂ exhibits a good photocatalytic property owing to the extension of the light response range to visible light and the efficient separation of photogenerated electrons and holes between α-Fe₂O₃ and amorphous TiO₂.     

Shape Controlled Preparation,Characterization and Gas Sensitivities of Shuttle-like Cr-doped α-Fe2O3 Nanoparticles

α-Fe2O3 nanoparticles doped with various mol% Cr3+ have been synthesized by a forced hydrolysis route, and were characterized by XRD, SEM, XPS and ICP techniques. The particles reserve shuttle-like shape in the presence of Cr3+ ions. The crystallite sizes of Fe2O3 become smaller with the increased Cr3+ concentration in solution. The responses of Cr doped α-Fe2O3 sensors were studied towards reducing gases such as ethanol, methanol, acetone, gasoline and n-hexane. Gas sensors based on these materials have higher sensitivities and rapid response/recovery time to alcohol than to hydrocarbon.     

α-Fe_2O_3 immobilized benzimidazolium tribromide as novel magnetically retrievable catalyst for one-pot synthesis of highly functionalized piperidines

Nanostructured α-Fe_2O_3 were prepared by precipitation followed by calcination method.Cetyltrimethylammonium bromide(CTAB) was used as surfactant.The nano α-Fe_2O_3 was then silanized with(3-chloropropyl)-triethoxysilane(CPTES) by room temperature mixing of α-Fe_2O_3 and CPTES to produce silane coated α-Fe_2O_3(ClPr-Si@Fe_2O_3).As-synthesized ClPr-Si@Fe_2O_3 was functionalized via covalent grafting of benzimidazole to produce 3-(l-benzimidazole)Pr-Si@Fe_2O_3.This was further reacted with bromine to afford α-Fe_2O_3 immobilized benzimidazolium tribromide(α-Fe_2O_3-BIM tribromide).This ionic liquid(IL)α-Fe_2O_3 BIM tribromide was characterized by FT-IR,XRD,TEM,SEM,TGA,VSM,EDX and BET analysis.The as-synthesized IL tribromide was used as catalyst for one-pot synthesis of highly substituted piperidines.The method is greener in terms of solvent selection,recovery of the catalyst and efficiency.     

γ-Fe2O3纳米粉的低热固相制备及其电磁损耗特性(英)

The Fe(OH)₃ precursor was prepared by solid -state reaction with Fe(NO₃)₃·9H₂O, NaOH and dispersed poly-ethylene glycol at low heating temperature(25 ℃). Synthesis of iron oxide (γ-Fe₂O₃) nanoparticle was achieved by thermal decomposition of Fe(OH)₃·xH₂O precursor. The nanoparticle was characterized by TG-DTA, X-ray diffra-ction, TEM etc. The results showed that the nanoparticle was composed of γ-Fe₂O₃ and was a better absorber for electromagnetic wave within the low frequency band.     

γ-Fe2O3纳米纤维的丙酮敏感特性

采用静电纺丝法制备了PVP/FeC₆H₅O₇复合纳米纤维, 并将复合纤维在500 ℃高温烧结3 h, X射线衍射分析(XRD)表明, 烧结后的产物为正尖晶石结构的γ-Fe₂O₃晶体. 扫描电子显微镜(SEM)观测结果表明, 制得了直径均匀、 连续的复合纳米纤维, 其平均直径约为1000 nm; 烧结后的γ-Fe₂O₃纳米纤维保持了其连续性, 但纤维发生了收缩, 直径较烧结前小, 平均约为600 nm. 比表面积分析表明, γ-Fe₂O₃纳米纤维比表面积为57.18 m²/g. 气敏性能测试结果表明, 230 ℃为γ-Fe₂O₃纳米纤维检测丙酮气体的最佳工作温度. 在此温度下, γ-Fe₂O₃纳米纤维对丙酮气体表现出高响应度[S=6.9, c(Acetone)=7.88×10⁴ mg/m³]和线性度(7.88×10²~1.58×10⁵ mg/m³浓度范围内). 同时, γ-Fe₂O₃纳米纤维气体传感器件还表现出良好的长期稳定性.     

微乳液反应法制备α-Fe2O3超细粒子的研究

铁氧化物胶体微粒的制备具有重要的意义，因为这些氧化物不仅具有理论研究价值，而且在催化、防腐、颜料以及磁记录材料等研究领域都有广泛的应用．Matijevic’和Schemer山最初用三价铁盐的升温强迫水解法制备出多种形状的。－Fe。03和个FeOOH均匀胶体微粒．其后，我们和张玉亭等在无防尘设备的简化实验条件下，按照修改后的实验手续也成功地获得了均匀球状。一饱0。、驷0。等胶体粒子K司，并对制备条件作了进一步研究则．但这些方法所能得到的最小粒子直径约为50urn．考虑到微乳液体系具有分散相液滴极其微小而且又很均匀的特点，本文…     

Phase equilibria in the system NiO-V2O5-Fe2O3 in subsolidus area

Reactivity of FeVO₄ towards Ni₂V₂O₇ and Ni₃V₂O₈ in the solid state was investigated. On the base of XRD and DTA results, phase diagrams in subsolidus area of the FeVO₄-Ni₂V₂O₇ and FeVO₄-Ni₃V₂O₈ intersections of the ternary system NiO-V₂O₅-Fe₂O₃ have been worked out and the phase diagram of this ternary system in subsolidus area in the whole component concentration range has been verified. This revised version was published online in July 2006 with corrections to the Cover Date.     

2-Hydroxymalonitrile-A Useful Reagent for One-step Synthesis of α-Hydroxy Esters

An efficient one-pot synthesis of α-hydroxy esters by employing the useful reagent 2-hydroxymalononitrile reacting with an aldehyde or ketone in just one step has been reported.     

氧化共沉淀法制备纳米级掺锑α—Fe2O3气敏陶瓷粉料

氧化共沉淀法制备纳米级掺锑α┐Ｆｅ２Ｏ３气敏陶瓷粉料王忠春＊＊刘尔生陈耐生＊黄金陵（福州大学化学系福州３５０００２）关键词α－Ｆｅ２Ｏ３陶瓷，锑掺杂气敏材料，纳米材料１９９６－１０－０５收稿，１９９７－０４－２２修回福建省科委资助项目＊＊现在上海硅酸...     

纳米α-Fe2O3/(IPDI-HTPB)复合粒子的制备及其催化性能研究

为改善纳米α-Fe₂O₃在复合推进剂中的分散性，提高其催化性能，选择推进剂的配方组分固化剂异氟尔酮二异氰酸酯（IPDI）为嫁接桥梁，将端羟基聚丁二烯（HTPB）接枝在纳米α-Fe₂O₃粒子的表面，制得纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子.首先研究了IPDI与HTPB反应动力学，优化制备条件；然后采用X射线衍射仪（XRD）、透射电子显微镜（TEM）、傅里叶变换红外光谱仪（FTIR）和热重分析（TGA）等手段对复合粒子的结构进行表征，采用DTA对比了复合前后纳米α-Fe₂O₃粒子对高氯酸铵（AP）热分解的催化性能的影响.结果表明，依靠IPDI的偶联作用，可将HTPB接枝在纳米α-Fe₂O₃的表面，包覆层厚度约为5 nm，改性后的纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子的分散性大幅提高，纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子对AP的热分解的催化性能也明显优于纯纳米α-Fe₂O₃粒子.     

水热合成制备Al掺杂α-MnO2纳米管及其超级电容器电化学性能

通过水热法制备了未掺杂α-MnO₂和Al 掺杂α-MnO₂, 对产物的形貌、结构和电化学性能进行了研究. 扫描电镜(SEM)和高分辨透射电镜(HRTEM)观察表明制备产物呈纳米管形态. 紫外-可见光谱分析计算了产物的能带间隙: 随着Al 的掺杂, α-MnO₂的能带间隙值降低. 以未掺杂α-MnO₂与Al 掺杂α-MnO₂作为电极材料, 通过循环伏安(CV)和恒流充放电测试电极的超级电容器性能. 在50 mA·g^-1电流密度下, 未掺杂α-MnO₂与Al 掺杂α-MnO₂电极的比电容分别达到了204.8 和228.8 F·g^-1. 电化学阻抗谱(EIS)分析表明Al 的掺杂降低了α-MnO₂在电解液中的阻抗, 有利于提高其电化学比电容. 增强的比电容及在1000个循环后仍具有良好的容量保持率,使Al 掺杂α-MnO₂在超级电容器中具有较好的应用前景.     

痕量甲胎蛋白的免疫纳米金催化-氧化亚铜微粒共振散射光谱分析

用粒径15 nm 的纳米金标记单克隆羊抗人甲胎蛋白(GAFP), 制备了甲胎蛋白(AFP)的免疫纳米金探针(AuGAFP). 纳米金及AuGAFP均对葡萄糖还原铜(Ⅱ)生成Cu₂O微粒这一慢反应具有较强的催化作用, Cu₂O微粒在620 nm处产生1个较强的共振散射峰. 将AFP-AuGAFP免疫反应与离心分离技术结合, 建立了超痕量AFP的免疫纳米金催化-Cu₂O微粒共振散射光谱新方法. 随着AFP浓度的增大, AFP-AuGAFP免疫复合物微粒增多, 离心液中AuGAFP浓度降低, 620 nm处的共振散射光强度I_{620 nm}线性降低, 其降低值ΔI_RS与AFP质量浓度ρ(AFP)在0.10～16.0 ng/mL范围内呈现良好的线性关系, 其回归方程为ΔI_RS=4.27ρ(AFP)+1.28, 检出限为0.05 ng/mL. 本方法所用试剂易得, 反应易控制, 灵敏度高, 选择性好, 用于定量分析人血清中的AFP, 结果令人满意.     

Synthesis of α-Oxoketene CyclicO,S and S,S Acetals

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Cu2O/Ag纳米复合物的表面增强拉曼光谱

用一种简单的化学还原方法制备了银纳米粒子包覆的氧化亚铜（Cu2O）纳米复合物。扫描电子显微镜显示Cu2O 为八面体型的纳米粒子,表面光滑,结构对称。包覆的Ag部分占据Cu2O粒子表面。通过比较Ag/Cu2O纳米复合物、Ag溶胶及Cu纳米粒子表面吸附的4-巯基吡啶（4-Mpy）分子表面增强拉曼光谱（SERS）发现,利用此方法得到了Cu2O粒子表面吸附分子的拉曼光谱。银纳米粒子所产生的电磁场增强又增强了吸附在Cu2O上的4-Mpy拉曼信号。这种方法为初步研究Cu2O表面吸附分子性质提供了依据,扩宽了SERS的使用范围,使SERS应用在纳米半导体材料上成为可能。     

KF/K2CO3/Al2O3催化合成香豆素

以Al2O3负载KF/K2CO3催化合成香豆素,水杨醛100 mmol,n(水杨醛)∶n(乙酸酐)∶n(KF/K2CO3/Al2O3)=1.0∶3.0∶0.3,于165℃反应2 h,香豆素产率高达89.8%。     

金负载量对低温水煤气变换Au/α-Fe2O3催化剂结构和性能的影响

采用共沉淀法制备了低温水煤气变换Au/α-Fe2O3催化剂。通过正交实验优化催化剂的还原活化条件，考察了金负载量对催化剂性能的影响。采用BET、XRD、UV-VIS、XRF、H2-TPR和O2-TPO等表征手段对催化剂的结构进行分析，并与其催化性能进行关联。结果表明，（1）采用10%-H2/N2还原气将催化剂在150 ℃原位还原9 h，其催化活性最高；（2）金的最佳负载量为8.00%，此时在催化剂制备过程中金的流失量较少，金粒子较小，也有利于抑制催化剂在反应过程中烧结；（3）TPR-TPO结果表明，金的负载量为8.00%时，Au/α-Fe2O3催化剂具有较易被还原、不易被氧化的性质，从而显示出最高催化活性。（4）Au/α-Fe2O3催化剂中的金以单质金（Au0）形式存在；其高活性与Au0-Fe3O4间的协同作用有关。     

Na2O或K2O对气相合成1–苯基氮杂环庚烷的CoO/SiO2-Al2O3催化剂的作用

研究了Na2O或K2O对苯胺和1,6己二醇气相合成1-苯基氮杂环庚烷的CoO/SiO2-Al2O3催化剂的作用,并采用X射线衍射、透射电子显微镜、H2-程序升温还原、NH3-程序升温脱附等技术对催化剂进行了表征.结果表明,Na2O助剂能增加催化剂的弱酸中心数,减少中强酸中心数,使催化剂的选择性得到提高.加入K2O使催化剂的弱酸中心数显著减少,并使CoO在反应过程中易于烧结,因此不利于1–苯基氮杂环庚烷的合成.     

A novel CuFe2O4@Ag nanocomposite biosynthesized by Spirulina platensis exhibits an anticancer effect on human gastric adenocarcinoma and Michigan Cancer Foundation-7 breast cancer cell lines

In recent years, the increasing cancer incidence and mortality rate has posed a significant challenge to scientists to develop novel therapeutic drugs against cancerous cells. One of the investigated techniques for cancer therapeutics is the green synthesis of nanoparticles (NPs). In this study, we reported the green synthesis and characterization of the CuFe₂O₄@Ag nanocomposite using Spirulina platensis and its cytotoxic activity on two cancer cell lines: human gastric adenocarcinoma (AGS) and Michigan Cancer Foundation-7 (MCF-7) breast cancer. The physical and chemical properties of the biosynthesized nanocomposite were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, dynamic light scattering, ultraviolet–visible spectroscopy, scanning electron microscopy, transmission electron microscopy, and zeta potential analyses. The anticancer properties of the CuFe₂O₄@Ag nanocomposite and imatinib drug on both cancer cell lines were evaluated using 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay. Also, apoptosis induced by the nanocomposite was assessed using annexin V/propidium iodide staining followed by flow cytometry analysis, Hoechst 33432 staining, and caspase-3 activity assay. Finally, the effect of the CuFe₂O₄@Ag nanocomposite on the expression of BAX and BCL2 genes was assessed by real-time polymerase chain reaction. The result of the MTT test showed an increase in the cellular uptake of CuFe₂O₄@Ag nanocomposite and cell viability loss in a concentration-dependent manner with the 50% minimum inhibitory concentration (IC₅₀) of 180 and 220 μg/ml for MCF-7 and AGS cell lines, respectively. The mean expression of BAX was significantly higher than that of BCL2 in cells treated with the nanocomposite. The results of flow cytometry, Hoechst 33432 staining, and caspase-3 activity assay indicated the stimulation of apoptosis through an increase in caspase-3 and nucleus fragmentation. In general, our results demonstrated the cytotoxic activity of the CuFe₂O₄@Ag nanocomposite. However, further in vivo studies are required to evaluate the accumulation of this nanocomposite in organs such as liver, kidneys, brain, and testes and its potential toxic effects.     

Synthesis and characterization of Al2O3/Cr2O3-based ceramic pigments

The synthesis and the characterization of Al₂O₃-based nanocrystalline inorganic pigments are reported. The pigments were synthesized by the polymeric precursor (Pechini method) using Cr₂O₃ as chromophore. XRD results only evidenced the corundum phase. The average particle size was about 34 nm. The samples were also characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG), and CIE-L*a*b* calorimetry. The pigments obtained in this work presented different colors, ranging from green to rose. This revised version was published online in August 2006 with corrections to the Cover Date.