WC/纳米碳管复合材料制备及其电化学性能

碳化钨具有类铂催化性能和较强的抗中毒能力, 但其催化活性远低于铂等贵金属催化剂. 如何提高其催化活性是碳化钨应用研究所面临的主要难点与热点之一. 为寻找改善碳化钨催化性能的技术方法, 本文将表面修饰与原位还原碳化技术相结合, 成功制备了碳化钨/纳米碳管复合材料, 采用XRD, HRTEM等手段对其形貌和晶相组成进行了表征, 并应用粉末微电极对其电催化性能进行了评价. 实验结果表明, 样品由碳化钨颗粒和纳米碳管组成, 碳化钨为形态不规则纳米颗粒, 均匀地生长于纳米碳管的外表面; 在碱性溶液中, 复合材料对对硝基苯酚的电催化性能明显强于具有介孔结构的纯碳化钨样品. 这说明将碳化钨复合到纳米碳管的外表面是提高碳化钨电催化活性的有效技术方法之一.     

β-环糊精修饰的金纳米粒子:催化应用及分子选择性（英文）

利用NaBH_4和L-半胱氨酸(L-Cys),采用一种简单的还原方法合成了L-Cys-β-CD@A NPs纳米粒子.研究了L-Cys-β-CD@AuNPs对4-硝基苯酚和4-硝基-1-萘酚的还原催化活性,结果表明:L-Cys-β-CD@AuNPs纳米粒子对4-硝基苯酚和4-硝基-1-萘酚的还原活性不同,由于β-环糊精(β-CD)与不同客体分子的选择性结合,对不同底物具有不同的催化活性.实验结果表明, L-Cys-β-CD@AuNPs对4-硝基-1-萘酚的还原反应效率优于对硝基苯酚.     

Pt/纳米碳管空气电极氧还原反应的电催化性能

以不同质量比的铂、纳米碳管、活性炭为催化层制备空气电极并测定其稳态极化曲线和交流阻抗.研究发现,纳米碳管经硝酸处理后其氧还原反应性能得到提高,特别是将表面氧化后再沉积Pt,对氧的电还原反应影响更显著.以质量比4∶1的活性炭/纳米碳管载Pt制备的空气电极,在过电位ηc为500～600mV下,氧还原电流可达600～700mA·cm-2.EIS测试表明,纳米碳管载Pt后的欧姆极化阻抗和电化学阻抗均非常小.     

对硝基苯酚在酸性介质中的电化学还原反应机理

采用电化学原位红外光谱技术研究了对硝基苯酚在铜电极表面及硫酸介质中的电化学反应机理. 对硝基苯酚首先经电还原反应生成对亚硝基苯酚和对羟胺苯酚, 对亚硝基苯酚可发生缔合生成反式二聚体, 最后在较低的电位下, 对羟胺苯酚经电还原生成了对氨基苯酚.     

CuFe_2O_4纳米粒子-石墨烯修饰电极测定对硝基苯酚

在玻碳电极表面修饰一层纳米CuFe_2O_4-石墨烯复合膜,研究了对硝基苯酚在复合膜上的电化学行为。该复合膜对对硝基苯酚具有明显的电催化作用,测得一对不可逆氧化还原峰电位分别为0.063 V和-0.020 V。考察了支持电解质种类、酸度、修饰层厚度和扫描速度等对对硝基苯酚伏安响应的影响。在优化实验条件下,氧化峰电流与还原峰电流在浓度为3.0×10~(-5)~1.0×10~(-4)mol/L的范围内呈现良好的线性关系,检出限为8.0×10~(-7)mol/L。方法应用于模拟水样中对硝基苯酚的测定,回收率为99.2%~101.1%。     

二氧化硅负载磷钼钒酸铯选择性催化硝化苯酚为邻硝基苯酚

采用溶胶-凝胶法制备了二氧化硅负载磷钼钒酸铯催化剂,利用XRD、红外、SEM以及物理吸附等技术手段对催化剂进行了表征分析,并以稀硝酸（30%）为硝化剂,考察了该催化剂对苯酚硝化反应的催化性能,系统研究了反应时间、催化剂用量、硝酸与苯酚用量以及催化剂重复利用等对催化反应的影响。 结果表明,制备的负载磷钼钒酸铯催化剂具有典型的Keggin结构,在温和的苯酚硝化反应条件下,表现出优良的催化活性和高的邻硝基苯酚选择性,在实验优化条件下,邻硝基苯酚收率达到88%,催化剂回收方便可多次重复使用。 负载磷钼钒酸铯催化苯酚硝化反应结合水蒸汽蒸馏提供了一种简单可行的制备邻硝基苯酚的方法。     

邻硝基苯酚在纳米TiO2膜修饰电极上的异相电催化还原

邻硝基苯酚在纳米TiO2膜修饰电极上的异相电催化还原;纳米TiO2膜电极;循环伏安;邻氨基苯酚     

纳米晶碳化钨薄膜对硝基甲烷还原的电催化性能

采用磁控溅射物理气相沉积技术在金属镍基体上制备碳化钨纳米晶薄膜. 薄膜具有纳米晶结构, 由粒径为20~35 nm的晶粒构成, 晶粒分布均匀, 晶相结构为非化学计量比的碳化钨(WC1-x). 采用电化学方法研究硝基甲烷在纳米晶碳化钨薄膜电极上的电化学还原性能和反应机理. 实验结果表明, 碳化钨薄膜电极对硝基甲烷电化学还原反应具有较好的催化性能, 当电极电位为-0.89 V(vs.SCE)时, 硝基甲烷还原为甲基羟胺的电流达14.9 mA/cm2, 其反应表观活化能为12.3 kJ/mol. 硝基甲烷在碳化钨薄膜电极上经过一步不可逆的电化学反应还原成甲基羟胺, 其控制步骤是电极反应的电荷传递过程.      

氧化铝模板上定向纳米碳管的快速生长及超声切短

在阳极氧化铝（AAO）模板上电沉积催化剂,快速生长了定向纳米碳管,纳米碳管以顶部生长模式生长.采用了超声的方法来切短露头于AAO模板的纳米碳管,增加纳米碳管膜的定向性.结果显示随着超声时间的增加,纳米碳管的定向性增加.位于纳米碳管膜顶部的催化剂在碳管切短的同时被去除,得到了顶部开口的纳米碳管.解释了纳米碳管被超声切短的机理.     

一维纳米Co_3O_4,Ag/Co_3O_4及CuO/Co_3O_4的合成与电催化性能(英文)

采用水热合成法制备了Co3O4及复合Ag/Co3O4、CuO/Co3O4一维纳米产品。用XRD,FE-SEM和TEM手段对产品进行了表征。采用循环伏安法研究了合成产品修饰的玻碳电极在碱性溶液中对对硝基苯酚的电催化还原性能。与裸玻碳电极相比,1mmol·L-1的对硝基苯酚在用Co3O4、特别是CuO/Co3O4修饰的玻碳电极上还原的峰电流明显增大,用Ag/Co3O4(Ag/Co原子比分别为1∶5和2∶5)修饰的玻碳电极催化还原对硝基苯酚时,尽管还原峰电流增大不是太大,但其峰电位明显降低(分别降低0.265和0.371V)。     

压缩集结碳纳米管电极对活性艳红染料的电催化降解研究

采用浓硝酸回流、高温焙烧、高温焙烧结合高速球磨的方法对碳纳米管进行前处理. 通过低温氮吸附法测定碳纳米管的比表面积; 透射电子显微镜观察碳纳米管处理前后的形貌结构; 红外光谱分析碳纳米管处理前后的官能团变化; 拉曼光谱分析处理前后的碳纳米管中无定形碳和石墨碳含量的变化; 将处理前后的碳纳米管制成电极, 作为电催化阳极来处理模拟染料废水活性艳红X-3B溶液. 实验结果表明: 经处理后制成的碳纳米管电极, 其稳定性及对染料溶液的电催化降解效率都有显著提高, 高温焙烧结合高速球磨为最佳的前处理方法.     

Separation of carbon nanotubes by frit inlet asymmetrical flow field-flow fractionation

Flow field-flow fractionation (flow FFF), a separation technique for particles and macromolecules, has been used to separate carbon nanotubes (CNT). The carbon nanotube ropes that were purified from a raw carbon nanotube mixture by acidic reflux followed by cross-flow filtration using a hollow fiber module were cut into shorter lengths by sonication under a concentrated acid mixture. The cut carbon nanotubes were separated by using a modified flow FFF channel system, frit inlet asymmetrical flow FFF (FI AFIFFF) channel, which was useful in the continuous flow operation during injection and separation. Carbon nanotubes, before and after the cutting process, were clearly distinguished by their retention profiles. The narrow volume fractions of CNT collected during flow FFF runs were confirmed by field emission scanning electron microscopy and Raman spectroscopy. Experimentally, it was found that retention of carbon nanotubes in flow FFF was dependent on the use of surfactant for CNT dispersion and for the carrier solution in flow FFF. In this work, the use of flow FFF for the size differentiation of carbon nanotubes in the process of preparation or purification was demonstrated.     

激光辐照对二茂铁掺杂单壁碳纳米管的影响

以单壁碳纳米管和二茂铁为原料, 采用气相扩散法合成填充率较高的二茂铁掺杂单壁碳纳米管(Fc@SWNTs)的复合材料. 考察激光辐射对样品的影响, 结果表明, 当激光功率达到20 mW时, 对样品进行10 s辐照, 样品的拉曼光谱出现了稳定的新峰. 对比分析发现, 二茂铁在激光辐照后形成了碳化铁, 同时部分碳源转化成碳管形成了双层碳管. 表明碳化铁是二茂铁裂解向内层碳管转化的中间产物.     

氢键型碳纳米管增强自修复复合材料的制备和表征

使用低聚酸、二乙烯三胺以及尿素为原料,碳纳米管为增强剂,制备出兼具良好力学性能和室温(30 ℃)自修复性能的氢键型自修复复合材料,同时对材料通过氢键进行自修复的机制进行了合理推测。 首先,对不同碳纳米管添加量的自修复材料进行应力-应变性能测试。 结果发现,随着碳纳米管的添加,材料的应力、应变均有所提高,添加质量分数9%碳纳米管时,材料的应力达到4.1 MPa、应变达到6%以上。 对添加质量分数9%碳纳米管的自修复材料进行表面形态、自修复性能以及热稳定性能测试。 结果表明,碳纳米管与材料有良好的相容性,材料的表面与切面形态相似;在室温下自修复24 h,自修复效率达到100%;10次断裂-修复循环中自修复效率仍能保持90%以上;材料具有良好的热稳定性,最大失重速率下的温度为474.3 ℃。 为下一代类皮肤传感器以及可穿戴智能设备提供了一种选择,为未来该类型自修复聚合物复合材料在高拉伸强度领域的应用奠定了技术基础。     

Carbon nanotubes as conducting support for potential Mn-oxide electrocatalysts: Influences of pre-treatment procedures

Different oxygen and nitrogen containing functional groups were created on the surface of the multiwalled carbon nanotubes. The multi-walled carbon nanotubes were treated in ultrasonic bath with sulfuric or nitric acid. Furthermore the surface texture was modified by increase of the roughness. In particular after treatment with the oxidizing nitric acid, in comparison to the H_2SO_4 or ultra-sonic treated samples,craters and edges are dominating the surface structures. Manganese oxide was deposited on the multiwalled carbon nanotubes by precipitation mechanism. Various manganese oxides are formed during the deposition process. The samples were characterized by elemental analysis, microscopy, thermal analysis,Raman spectroscopy, and by the zeta potential as well as X-ray diffraction measurements. It was shown that the deposited manganese oxides are stabilized rather by surface texture of the multi-walled carbon nanotubes than by created functional groups.     

Chemical Surface Treatment for Highly Improved Dispersibility of Multi‐Walled Carbon Nanotubes in Water

In order to increase the dispersibility of multi‐walled carbon nanotubes (MWNTs) in water without any additives, various acid treatments were used. Generally, acid treatment used to remove or purify carbon nanotubes. MWNTs treated with a mixture of nitric and sulfuric acids showed high dispersion stability by means of UV‐visible spectrophotometry and higher crystallinity than other samples. In addition, it was clearly shown that acid treatment efficiently removed the impurities of MWNTs, which was proven by thermogravimetric analysis. In particular, one of functional groups, cyano (C‐N) bonding characterized by Fourier transform‐infrared after acid treatment were formed the surface of MWNTs.     

Near-edge X-ray absorption fine structure spectroscopy-assisted purification of single-walled carbon nanotubes

Single-walled carbon nanotubes were produced by the conventional arc discharge method, and purified with a two-step treatment. First, the raw soot containing single-walled carbon nanotubes was burned up at ca. 350 °C in air to remove amorphous carbon, and then it was treated by strong acidic solvents to remove metal catalysts. Near-edge X-ray absorption fine structure spectroscopy was applied to analyze the defects on single-walled carbon nanotubes in whole purification process, so the experimental conditions can be optimized, and finally high-purity single-walled carbon nanotubes were obtained as revealed by various spectroscopic characterizations such as scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and Raman spectroscopy.     

碳纳米管的化学修饰以及作为润滑油添加剂的摩擦学性能研究

采用硫酸和硝酸混合酸对催化裂解法(CVD法)制备的多壁碳纳米管(MWNNTs)进行纯化，然后运用硬脂酸对碳纳米管进行表面修饰，并研究了硬脂酸修饰后的碳纳米管的表面状况以及作为润滑油添加剂的摩擦学行为．实验结果表明，在硫酸催化剂作用下，通过酯化反应碳纳米管能够被硬脂酸包覆，并且硬脂酸修饰的碳纳米管作为润滑油添加剂能够显著提高基础油的减摩抗磨性能，当添加量为0．15％左右时，润滑油的减摩抗磨性能最佳，与基础油相比可以使摩擦系数下降10％左右，磨损量下降30％～60％．     

Effect of carbon nanotubes dispersed in binder on properties of epoxy nanocomposite

Effect of quality parameters of starting raw materials, native carbon nanotubes (degree of defectiveness, thermal stability, morphology) on the properties of carboxylated and amidated nanotubes produced from these raw materials and on the homogeneity of a dispersion of amidated nanotubes in an epoxy oligomer was studied. The physicomechanical properties of epoxy nanocomposites produced from these dispersions were examined. It was found experimentally that an increase in the defectiveness of native nanotubes leads to a rise in the size of numerous aggregates in dispersions composed of an epoxy resin and amidated carbon nanotubes and, as a result, to deterioration of the physicomechanical characteristics of epoxy nanocomposites based on these dispersions.     

碳纳米管的功能化及其电化学性能

超级电容器作为一种新型的储能元件,以其快速储存、释放能量等优点,近年来成为各国科研工作的研究重点和焦点[1￣3],并在数据记忆存储系统、便携式仪器设备、后备电源、通讯设备、计算机、燃料电池、电动车混合电源等许多领域都有广泛的应用前景[4]。目前,超级电容器用的电极材