Surface Oxidized Carbon Nanotubes Uniformly Coated with Nickel Ferrite Nanoparticles

We report a facile non-templated hydrothermal synthesis method for the production of nickel ferrite (NiFe₂O₄)/carbon nanotube nanocomposite comprised of oxidized multi-walled carbon nanotube (o-MWCNT) uniformly coated with nanoparticles of NiFe₂O₄ (1–5 nm). The carboxylate groups of the o-MWCNT coordinate the nanoparticles strongly at its surface, and the size of the NiFe₂O₄ particles can be controlled by the subtle variation of reaction time and the quantity of o-MWCNT used. We believe that this method can be extended to allow the uniform coating of different spinel-type materials onto o-MWCNT and other nanocarbon materials.     

镍纳米管的电化学组装与表征

以多孔阳极氧化铝（AAO）为模板,通过敏化和活化处理,再采用电化学方法沉积镍,组装成具有稳定结构的镍纳米管。透射电镜（TEM）分析表明,镍纳米管的管径在纳米范围内,长度最长可达微米。实验表明：适当的敏化和活化条件,以及电化学沉积镍时的电流和时间是影响镍纳米管生长的关键因素。     

钙锰修饰磁性碳纳米管的制备与表征

通过化学共沉淀法制备钙锰修饰的磁性碳纳米管复合材料,将其用于吸附去除水中腐殖酸(HA)并再生重复使用.研究了制备条件中钙、锰在磁性碳纳米管上负载的顺序,锰、钙配比对吸附及再生的影响,通过正交试验对制备条件进行优化.通过扫描电镜(SEM)、X射线衍射(XRD)、红外光谱(FT-IR)、比表面积(SSA)及振动样品磁强(VSM)对材料表征.结果 表明,复合材料上成功负载磁性铁氧化物、MnO2和CaCO3.比表面积为171.73 m2/g,饱和磁化强度为13.27 emu/g.对于20 mg/L HA,材料投加量0.75 g/L,30 min HA去除率为88.11％,微波辐照10 min再生率为100.26％.钙锰修饰的磁性碳纳米管是一种具有良好HA去除效果又能高效微波再生的有潜在应用前景的水处理纳米材料.     

共沉淀水热法制备锰锌铁氧体纳米晶及其表征

本研究采用成本低,污染少的共沉淀法制备锰锌铁氧体前驱体后再采用水热法制备出最终的纳米锰锌铁氧体粉末.利用X-射线衍射(XRD)、透射电镜(TEM)、复磁导率等测试手段对材料的形貌、粒径、和吸波性能进行了表征和分析.研究反应物的种类及配比对锰锌铁氧体吸波性能的影响,当反应物采用氯化锰、氯化锌、氯化铁,m(Mn)∶ m(Zn)∶ m(Fe) =4∶ 1∶10,得到Mn08Zn0.2Fe2O4粒子,透射电镜分析表明,其粒子呈球状,粒径在10 ～ 20 nm.网络矢量分析仪表明,当吸收厚度为2 mm时,锰锌铁氧体材料的吸波性能最佳.     

氮化硼纳米管的合成与表征

以氧化铁和无定型硼粉为原料,反应气氛为碳气氛,在1 400℃下利用化学气相沉积法（CVD）制备出氮化硼纳米管。X射线研究表明,对应着六方氮化硼晶面的特征衍射峰非常清晰。采用扫描电子显微镜（SEM）对样品的结构与形貌进行表征,结果表明,样品属于一端开口的竹节状BN纳米管。     

Sonochemical Combined Synthesis of Nickel Ferrite and Cobalt Ferrite Magnetic Nanoparticles and Their Application in Glycan Analysis

The combination of the sonochemical activation of Ni(NO₃)₂ and Co(NO₃)₂ in the presence of Fe(NO₃)₃ and polyethylene glycol and consecutive heat treatment of the formed metal hydroxides offers a cheap and efficient method for the preparation of nickel ferrite and cobalt ferrite magnetic nanoparticles, which can be successfully applied in the selective capture of fluorescently derivatized N-glycans from human serum. XRD measurement revealed that, besides the ferrite phase, nickel and cobalt oxides also form during heat treatment. The amount of simple metal oxides can be well controlled by the temperature of the heat treatment, since increasing temperature yielded higher spinel content. For both nickel and cobalt, the best heat treatment temperature was found to be 673 K, where the samples contained 84.1% nickel ferrite, and in the case of cobalt, almost pure (99.6%) cobalt ferrite could be prepared. FT-IR and zeta potential measurements indicated the presence of surface OH groups, which aided in the dispersion of the particles in water and, in addition, can promote the adsorption of polar compounds. The practical applicability of the magnetic nanopowders was demonstrated in the purification of fluorescently derivatized N-glycans (from human serum). Cobalt ferrite was found to be the most effective. Owing to the easy preparation and the simplicity of the magnetic separation the pure cobalt ferrite, magnetic nanoparticles could be efficient tools for the selective enrichment of serum N-glycans in HPLC measurements.     

Ti-Mn-Cu替代的M-型钡铁氧体的制备和表征

为了改善钡铁氧体的性能,利用共沉淀-熔盐法制备了Ti、Mn、Cu掺杂的M型钡铁氧体,借助各种分析手段对样品进行了表征.结果表明:制备的样品呈现平面六角形结构,粒径在50mm左右.助熔剂对样品粒径的影响很小,对样品形貌的影响很大.得到这样的结论:经由共沉淀一熔盐法制备的Ti、Mn、Cu掺杂的M型钡铁氧体在助熔剂与前驱体比为(质量比)0.75∶1时获得规则的六角形并具有最佳的磁性能:σS(26.58e.m.u/g),Hc(3580 Oe),σr(15.18e.m.u/g).     

类竹节状氮掺杂碳纳米管的制备及性能的研究

本文以三聚氰胺（C3N6H6）为原料,通过高温热分解法成功的制备了氮掺杂碳纳米管（N—CNTs）。据SEM和TEM图像显示,所制备的N—CNTs呈竹节状,并且直径和壁厚统一。利用FTIR图谱分析了N—CNTs的结构和官能团组成。同时,对N—CNTs的发光特性进行了研究,发现样品在蓝紫光范围内具有发光特性,这使得其在光学纳米器件方面具有潜在的应用价值。     

Kinetics of Nickel Ferrite Formation

The rate of nickel ferrite formation is influenced by the milling technique and in the case of wet milling by the type of liquid media used. The reactivity of different types of α-Fe₂O₃ of spherical shape decreases with an increase of the surface area ratio of α-Fe₂O₃ to NiO. The particle shape of the iron oxides also affects their reactivity; cubical α-Fe₂O₃ has the least reactivity in the formation of nickel ferrite. The validity of Jander's equation in ferrite formation is reviewed. Based on present findings the rate of ferrite formation is best represented by the equation dx / dt = ( a - x) / t , in which x is the percentage of ferrite formed, t the time, and a the kinetic isothermal reaction rate coefficient which is related to the surface area ratio of the reacting oxides. The application of the foregoing equation to the formation of magnesium ferrites from data found in the literature is also satisfactory.     

Template-Assisted Synthesis and Characterization of Passivated Nickel Nanoparticles

Potential applications of nickel nanoparticles demand the synthesis of self-protected nickel nanoparticles by different synthesis techniques. A novel and simple technique for the synthesis of self-protected nickel nanoparticles is realized by the inter-matrix synthesis of nickel nanoparticles by cation exchange reduction in two types of resins. Two different polymer templates namely strongly acidic cation exchange resins and weakly acidic cation exchange resins provided with cation exchange sites which can anchor metal cations by the ion exchange process are used. The nickel ions which are held at the cation exchange sites by ion fixation can be subsequently reduced to metal nanoparticles by using sodium borohydride as the reducing agent. The composites are cycled repeating the loading reduction cycle involved in the synthesis procedure. X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron microscopy, Energy Dispersive Spectrum, and Inductively Coupled Plasma Analysis are effectively utilized to investigate the different structural characteristics of the nanocomposites. The hysteresis loop parameters namely saturation magnetization and coercivity are measured using Vibrating Sample Magnetometer. The thermomagnetization study is also conducted to evaluate the Curie temperature values of the composites. The effect of cycling on the structural and magnetic characteristics of the two composites are dealt in detail. A comparison between the different characteristics of the two nanocomposites is also provided.     

Mechanochemical Synthesis and Electrochemical Characterization of Nano Crystalline Calcium Ferrite

Abstract  

The studies on the mechanochemical synthesis and electrochemical characterization of orthorhombic calcium ferrite (CaFe₂O₄) are reported in this paper. Stoichiometric mixtures of α-Fe₂O₃ and granulated Ca metal were used as the starting materials for the synthesis process. The synthesized calcium ferrite was characterized by room-temperature M?ssbauer spectra, XRD and TEM. The electrochemical characterisation was carried out using cyclic voltammetry studies. M?ssbauer spectra provide the yield of the reaction, information on the charge status, the local symmetry and the magnetic state of the iron ions in the mechanosynthesized ferrite material. XRD analysis of the CaFe₂O₄ compound reveals the orthorhombic crystal structure with an average crystalline size of about 28 nm. TEM micrographs reveal the nanoparticles with irregular crystal morphology ranging from 8 to 30 nm. The electrochemical studies clearly show that the calcium ferrite compound can act as an electrocatalyst for Oxygen Evolution Reaction (OER).     

玫瑰花状锂掺杂磷酸镍的水热合成及表征

采用水热法制备出玫瑰花状锂掺杂的磷酸镍催化剂,利用XRD、SEM、TEM、IR、UV-Vis等表征手段对所制备催化剂进行了物相和形貌的表征,并将其用于催化环氧丙烷异构化。结果表明,催化剂组成主要为NiNH_4PO_4·H_2O,未掺杂Li样品呈毛线球状,Li元素掺杂后的三个样品呈玫瑰花状,异构化反应中环氧丙烷的转化率较低。     

磷化镍微纳米材料的水热合成与表征

以无毒的红磷代替白磷作为磷源,以硝酸镍为镍源,利用水热合成法成功实现了磷化镍的温和制备。考察了磷和镍物质的量比、水热温度、水热反应时间和溶剂体系对磷化镍晶相组成及其形貌的影响。结果表明,在水热温度120℃,水热时间12h,原料初始磷和镍物质的量比为6时即可得到纯净的六方相的Ni_2P。磷和镍物质的量比增加有利于四方相结构的Ni_(12)P_5向六方相结构的Ni_2P转变,而温度升高则有利于Ni_2P向Ni_(12)P_5转变,通过控制磷和镍物质的量比和水热温度可以实现磷化镍的相态和形貌的可控合成。反应时间和乙二醇-水体系中溶剂体积比的变化,并未改变磷化镍的组成,但对产物的结晶度有一定影响。     

PSAF@淀粉无机-有机杂化絮凝剂的合成与表征

将粉煤灰与固体氢氧化钠混合焙烧活化,经酸浸、静置后引入淀粉和引发剂K2S2O8,通过水解、缩聚等步骤一步法合成聚硅酸铝铁(PSAF)-淀粉杂化絮凝剂,考察了淀粉添加量和引发剂用量对絮凝性能的影响.研究发现,当淀粉添加量为40%,引发剂用量为1%时,对低浊度模拟水样的浊度去除率最高可达76.3%.PSAF@淀粉杂化絮凝剂电导率随浓度呈现良好的线性关系,在1086 cm-1处保留更为明显的淀粉葡萄糖C-O-C伸缩振动吸收峰,半衰期温度也较PSAF-淀粉混合物要高,热稳定性更好,表明PSAF-淀粉杂化产物无机-有机间以共价键形式结合.     

改性多壁碳纳米管／聚氨酯乳液的制备与研究

以聚醚多元醇（N-210）、异佛尔酮二异氰酸酯（IPDI）、二羟甲基丙酸（DMPA）、一缩二乙二醇（DEG）为基料,合成了水性聚氨酯预聚体,采用改性多壁碳纳米管（ MWCNTs ）的悬浊液为分散介质得到水性聚氨酯复合乳液。通过TEM、拉力机、TGA对其胶膜的微观结构、力学性能以及热学性能进行测试,结果表明： MWCNTs均匀分散在聚氨酯胶膜中;当MWCNTs质量分数在0.5％时,拉伸强度达到最大值为17.91 MPa,比纯聚氨酯提高了81％;复合材料的断裂伸长率均达到500％以上,最大达到539％,明显高于未加改性碳纳米管的聚氨酯; MWCNTs的加入可明显提高复合材料的耐热性。     

Multi-wall Carbon Nanotubes Decorated with Bismuth Oxide Nanocrystals Using Infrared Irradiation and Diazonium Chemistry

A simple and efficient method using infrared (IR) irradiation is presented to decorate multi-wall carbon nanotubes (MWCNTs) with bismuth oxide nanocrystals (Bi₂O₃ NCs) using ammonium bismuth citrate (ABC) as Bi precursor. The present methodology comprises 4 steps: purification, functionalization, impregnation and calcination. Various techniques (XPS, TEM, PXRD, EDX, Raman and TGA) are used to characterize the resulting materials. The treatment with sodium hydroxide leads to the purification of MWCNTs (p-MWCNTs) which is confirmed by the absence of alumina. The chemical functionalization of p-MWCNTs with monocarboxylic aryl diazonium salts generated in-situ (p-MWCNTs-D1) followed by impregnation in the presence of IR radiation is the crucial step in homogeneously impregnating functionalized MWCNTs with ABC (p-MWCNTs-D1/ABC). Calcining p-MWCNTs-D1/ABC at optimum temperature results in a controlled decoration of Bi₂O₃ NCs in their pure phase. A bimodal distribution of Bi₂O₃ NCs on MWCNTs with a Gaussian mean diameter of ~?1.1 and ~?11.21 nm is evidenced. The originality of this work is the decoration of CNTs for the first time with Bi₂O₃ nanocrystals. Metastable β-Bi₂O₃ (tetragonal) crystal phase is noticed on the surface of CNTs. Electrical conductivity of the samples was assessed on bucky papers elaborated from the various modified MWCNTs. The present methodology is applicable to large-scale preparation which opens interesting perspectives for nanotechnology applications.     

镍纳米管的制备及电化学储氢性能

本文以多孔氧化铝(AAO)为模板,采用电化学沉积法制备了镍纳米管,通过透射电镜(TEM),能谱仪(EDX),选区电子衍射图(SAED)对镍纳米管的形貌、微观结构及组成进行了表征。并将所制备的镍纳米管制成微电极,用循环伏安法测试了其电化学储氢性能。结果表明,所制备的镍纳米管管径约20nm,管长可达微米级,且相比于镍粉,镍纳米管的电化学储氢性能更好。     

吡啶鎓阳离子对镍配合物的合成及表征

合成了马来二氰基二硫烯镍(Ⅱ)配合物[1-NaPhthMePyNH_2]_2[Ni(mnt)_2]([1-NaPhthMePyNH_2]~+为1-(1′-奈苄基)-2-氨基吡啶鎓离子),并用元素分析,UV,IR,单晶X射线衍射表征了其组成和结构。结果表明:配合物系三斜晶系,空间群P_(-1),a=0.764 78(15)nm,b=0.949 88(19)nm,c=1.360 9(3)nm,α=92.491(2)°,β=103.784(2)°,γ=105.723(2)°,V=918.0(3),Z=1。     

水扬酸镍的合成表征及结构分析

用流变相反应法合成了Ni(OH)Sal·H2 O和Ni2 (OH) 2 Sal2 ·H2 O。通过元素分析、TG、IR、XRD和磁矩对其结构进行了分析。结果表明两个配合物都属于单斜晶系 ,其晶胞参数为 ,Ni(OH)Sal·H2 O∶a =13.1179,b =11.36 41,c =9.5 6 0 5 ,β =92 .96 2 ,V =14 2 3.31(97) 3,Z =7,Dcalcd .=1.885 g/cm3,Dexpt=1.85 8g/cm3;Ni2 (OH) 2 Sal2 ·H2 O :a =13.12 17,b =11.35 80 ,c =9.5 5 2 2 ,β =92 .978 ,V =14 2 1.72 (95 ) 3,Z =4 ,Dcalc=2 .0 73g/cm3,Dexp=2 .0 0 0 g/cm3。     

Synthesis and Characterization of Mesoporous Hybrid Silica-Polyacrylamide Aerogels and Xerogels

We report the synthesis of highly porous hybrid silica-polyacrylamide aerogels where the inorganic network was obtained through the hydrolysis and poly-condensation of tetramethoxysilane via a two-step sol–gel process while the polyacrylamide polymer was made by photo-copolymerization of two organic monomers, the acrylamide and the bis-acrylamide. These aerogels were obtained after a carbon dioxide supercritical drying while the corresponding xerogels were dried by simple evaporation. These materials, as well as pure silica and polyacrylamide aerogels and xerogels, were characterized by FTIR spectroscopy, solid-state ²⁹Si and ¹³C NMR spectroscopy, Thermogravimetric Analysis, a nitrogen adsorption-desorption technique, and Scanning Electron Microscopy. The FTIR and NMR spectra and the TGA/DTA analyses confirm the coexistence of highly branched silica and polyacrylamide networks reflecting the hybrid nature of the materials obtained. Nitrogen adsorption measurements reveal high specific surface areas and pore size distributions disclosing the mesoporous character of these hybrid materials. Hybrid silica-polyacrylamide aerogels having a specific surface area equal to 572 m²/g and a pore volume 1.92 cm³/g were successfully prepared for the first time in this study. The high porosity of these aerogels is due to a better resistance of the silica network to capillary forces during the supercritical drying when silica coexists with a polyacrylamide network.