铁催化薄膜的微观结构对碳纳米管阵列生长的影响

本文利用热化学气相沉积法（TCVD），系统地研究了NH3预处理对硅基底上沉积的催化剂铁膜的结构及所制备的碳纳米管形态的影响。研究结果表明，利用氨气对硅基底上的催化剂铁膜进行适当的预处理不仅可以将催化剂颗粒细化，还可以使催化剂在碳纳米管的制备过程中保持较高的催化活性，促进分解出的活性碳原子在催化剂中扩散和析出，增强碳纳米管的成核和生长，从而合成出纯度较高、定向性好的碳纳米管阵列。     

用热CVD法制备片状碳纳米材料的研究

采用阳极氧化法在草酸溶液中制备了孔径约为100nm的多孔氧化铝(AAO)模板。利用此模板在不负载任何催化剂的条件下,利用热CVD装置制备出片状碳纳米薄膜,并对此片状薄膜做了SEM,TEM显微观察和EDS能谱分析,对其形成条件和生长机理等方面做了探讨分析,为在氧化铝模板上生长包括管状、片状、棒状等形状的碳纳米材料提供了一定的借鉴意义。     

竹节型结构碳纳米管的形成机制研究

利用化学气相沉积制备碳纳米管的过程中,在含氮的气体环境中,竹节型结构的碳纳米管在催化剂的作用下可制备出来.然而,目前对其形成机制仍不十分清楚.本工作中,分析化学气相沉积制备碳纳米管过程中催化剂的状态之后,研究了碳在不同状态催化剂中的扩散,提出了新的竹节型结构碳纳米管形成机制.     

衬底对沉积碳纳米管薄膜的影响

利用微波等离子体化学气相沉积(MPCVD)方法,分别在不锈钢衬底上和刻线的镍膜上直接沉积了碳纳米管膜。通过SEM、拉曼光谱和XRD表征,讨论了不同衬底对碳纳米管膜生长的影响。结果表明:在一定条件下,可在镍膜上沉积垂直于衬底的高度取向的碳纳米管,但在不锈钢衬底上却长出取向无序的碳纳米管膜,这说明衬底对碳纳米管的取向生长起着关键作用。     

CNTs-Pt甲醛传感器和CNTs-Au葡萄糖传感器的研究

采用化学气相沉积(CVD)技术,通过CH₄裂解法制备了碳纳米管(CNTs)。使用旋转圆盘处理机(SDP)自组装技术,将纳米Pt和纳米Au电沉积在CNTs上对其进行修饰。随后,通过将铂粒子电化学沉积在CNTs修饰的玻碳电极(GCE)上以及利用静电效应将葡萄糖氧化酶固定在金电极上,制备了CNTs-Pt/GCE和CNTs-Au修饰电极。最后,使用循环伏安法(CV)研究了葡萄糖在CNTs-Au和甲醛在CNTs-Pt/GCE上的电化学性能。结果表明,由于纳米金粒子与CNTs可以有效地增加电极的比表面积提高其电子转移速率,因此,CNTs-Au生物传感器具有良好的重复性、稳定性和快速的葡萄糖检测响应,可用于临床血清葡萄糖浓度的检测。另外,由于Pt的高度分散和CNTs与Pt的协同作用增强了电极表面的活性位点,使得CNTs-Pt/GCE在甲醛的检测过程中展现出了较高的灵敏度和良好的重现性。     

AAO纳米光栅结构参数对薄膜硅太阳能电池光吸收的影响研究

以多孔氧化铝(AAO)为模板设计了一种新型的纳米光栅背反射结构.采用微波工作室(CST MWS)软件对该结构进行仿真,研究AAO模板的孔径大小、孔径深度和占空比对薄膜硅太阳能电池光吸收的影响.仿真结果表明,以AAO为模板制备的新型背反射结构能够有效地延长光的传播路径,增加长波长光子的吸收.当孔径大小为157.2 nm,孔深为78.6 nm,占空比为0.5时,效果最佳.这与理论的计算结果相一致.     

沉积温度对PECVD制备碳纳米管形貌的影响

采用等离子体增强化学气相沉积技术,以C2H2、H2和N2为反应气体,在镀Ni催化剂的Si基底上成功制备出多壁碳纳米管薄膜.采用扫描电镜研究了沉积温度对碳管形貌的影响,进一步通过扩散机制分析了多种形貌CNTs的生长机制.结果表明:沉积温度对催化剂的刻蚀和碳纳米管薄膜的形成起着决定作用,获得定向性良好、分布均匀、密度适中的碳纳米管的最佳温度是700℃.     

CdS/TiO2纳米管阵列的制备及光催化性能

采用阳极氧化法在纯钛箔上制备出TiO2纳米管阵列,再通过化学水浴沉积法在TiO2纳米管阵列上负载CdS纳米颗粒.利用XRD、FESEM和UV-Vis分光光度计对样品的晶体结构、微观形貌和光学性质进行表征,并研究了不同含量CdS负载的复合薄膜对光催化降解气相苯性能的影响.结果表明,CdS纳米颗粒均匀沉积到TiO2纳米管阵列上,所制备的复合薄膜光吸收带边均扩展到了可见光区.CdS的修饰大幅度提高了TiO2纳米管阵列对气相苯的光催化降解活性,其中负载CdS质量分数为3;的TiO2纳米管阵列光催化活性最佳,80 min内对气相苯的去除率为80;,终产物CO2的浓度为640 mg/m3.     

硅基AAO模板内电化学沉积ZnO纳米线及其光电性能研究

本文利用二次阳极氧化法在p型低阻〈100〉晶向的硅衬底上制备了AAO/Si,以硅基AAO为辅助模板,采用电化学沉积的方法以Zn(NO3).6H2O和HMT(C6H12N4)为原料,在80℃的水浴槽中制备了ZnO纳米线结构。采用SEM,XRD和拉曼光谱等手段对ZnO/AAO/Si复合结构进行表征。SEM图表明ZnO纳米线已成功组装到AAO/Si模板里,直径约45 nm,长度约为600 nm。XRD和拉曼光谱表明ZnO具有六角纤锌矿多晶结构。光致发光(PL)谱图表明ZnO/AAO/Si复合结构在565 nm附近有较宽黄绿发射峰,在395 nm附近有微弱的紫外发射峰。场发射测试结果表明,ZnO纳米线的场增强因子的β值为2490,场增强因子很高,具有广泛的应用前景。     

DNA模板调控纳米无机材料生长

以DNA为模板诱导纳米无机晶体的生长是近年来一个新的研究方向.DNA模板具有完善和严密的分子识别功能,使其组装过程具有高度的选择性.通过人为控制DNA的形状、长度和序列,可以制备出不同结构的纳米功能材料.本文讨论了DNA模板诱导硫化镉、四氧化三铁、硫酸钡、氯化镁和二氧化硅等纳米无机晶体的生长.     

阵列式碳纳米管雷达波吸收性能研究

研究了阵列式碳纳米管的雷达波吸收性能.采用化学气相沉积(CVD)工艺制备阵列式碳纳米管薄膜,并采用SEM 和TEM 对其进行观测.观测显示:阵列式碳纳米管薄膜中碳纳米管排列规则,有很好的定向性,直径30～50 nm.阵列式碳纳米管薄膜平铺在铝板上并用环氧树脂固定制成试样,采用反射率扫频测量系统HP8757E矢量网络分析仪检测阵列式碳纳米管吸波性能.结果表明:阵列式碳纳米管在2～18 GHz频段的较高频段表现出良好的吸波性能.吸波性能随薄膜厚度不同而改变.阵列式碳纳米管薄膜厚度为0.2 mm 时,雷达波吸收性能最佳,峰值R为-15.87 dB,波峰出现在17.83 GHz,带宽分别为4.25 GHz(R<-10 dB)和6.40 GHz(R<-5 dB).     

阵列式碳纳米管微波受激发射光子

采用化学气相沉积工艺(CVD)制备阵列式碳纳米管(ACNT)薄膜并检测薄膜的微波性能.当ACNT薄膜受到微波照射时,强烈地发射光子,产生耀眼的的白光,红外测温仪显示温度高达1200℃,但ACNT并不氧化燃烧.ACNT薄膜经球磨成粉状后,光子发射性能消失,在微波照射下 ACNT粉末和普通碳纳米管(MWCNT)表现相近,吸收微波能量后开始燃烧并发出红色的火焰,实测温度为720℃.研究显示ACNT具有优异的场发射性能.     

The thermal stability of anodic alumina membranes at high temperatures

Nano‐structured anodic alumina membranes are ideal templates and have wide applications. However, anodic alumina materials begin to curl up at high temperatures. To better understand and overcome this problem, the thermal stability of anodic alumina membranes was investigated. Anodic alumina membranes obtained in oxalic acid electrolyte were heat treated in air at different annealing temperatures up to 1200 °C. Our results show that the sub‐pores produced during the annealing process are responsible for the curling. The repulsive forces between neighboring pores caused by mechanical stress at the metal nucleus/oxide interface promote the formation of the sub‐pores. Annealing under a suitable pressure provided thermal stability to the membranes, because it avoided or minimized curling and cracking phenomena. Scanning electron microscopy images showed that the sub‐pores disappeared when annealed under a suitable pressure.     

化学气相沉积法制备平直多壁碳纳米管的研究

本文研究了用焦炭还原二氧化碳后的一氧化碳作碳源,化学气相沉积法合成平直的多壁碳纳米管的工艺.研究表明在化学气相沉积条件下,用焦炭还原二氧化碳得到的一氧化碳在适当的铁基催化剂作用下,采用催化剂/碳原子共沉积的工艺可以生产出平直、并且内径很大的多壁碳纳米管.碳源中催化剂的浓度影响着纳米管的形成,而沉积温度对其没有影响.     

Synthesis and photoluminescence properties of ZnO nanowire arrays

In this paper we report a chemical method named coordination reaction method to synthesize ZnO nanowire arreys. ZnO nanowires with the diameter about 80nm were successfully fabricated in the channels of the porous anodic alumina (PAA) template by the above coordination reaction method. The microstructures of ZnO/PAA assembly were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The results showed that the ZnO nanowires can be uniformly assembled into the nanochannels of PAA template. The growth mechanism of ZnO nanowires and the conditions of the coordination reaction are discussed. Photoluminescence (PL) measurement shows that the ZnO/PAA assembly system has a blue emission band caused by the various defects of ZnO. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Controllable synthesis of well‐aligned CuO nanotube arrays using porous alumina templates

In order to further enhance the performance of CuO in currently existing applications, well‐aligned CuO nanotube arrays with different diameters were fabricated. During the synthesis process, porous anodic alumina films were fabricated, and then the synthesis of CuO nanotube arrays was realized by using the obtained porous anodic alumina films as templates. The morphology and structure of the obtained products has been confirmed by field‐emission scanning electron microscopy, transmission electron microscopy and X‐ray diffraction measurements. Due to the large surface area of the synthesized products, the prepared CuO nanotube arrays may have potential applications in catalyzing and gas sensing area.     

Growth of carbon nanotubes from waste blast furnace gases at atmospheric pressure

Carbon emissions from industrial sources are of major global concern, especially contributions from the steel manufacturing process which accounts for the majority of emissions. Typical blast furnace gases consist of CO₂ (20‐25%), CO (20‐25%), H₂ (3‐5%) and N₂ (40‐50%) and trace amounts of other gases. It is demonstrated that gas mixtures with these compositions can be used at atmospheric pressure to grow carbon nanotubes (CNTs) by chemical vapor deposition (CVD) on to steel substrates, which act as catalysts for CNT growth. Computational modelling was used to investigate the CNT growth conditions inside the CVD chamber. The results show that industrial waste pollutant gases can be used to manufacture materials with significant commercial value, in this case CNTs.     

Preparation of amorphous carbon nanotubes using attapulgite as template and furfuryl alcohol as carbon source

Amorphous carbon nanotubes were synthesized by vapor deposition polymerization (VDP) method using attapulgite as template and furfuryl alcohol as carbon source. The morphology and microstructure analysis of the as-prepared samples showed that highly pure amorphous carbon nanotubes were obtained, and determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SEAD) and energy dispersive X-ray (EDX) spectrum. The Brunauer–Emmett–Teller (BET) surface area analysis indicated that the specific surface area of the as-prepared amorphous carbon nanotubes reaches up to 503.1 m²/g. A hypothesis about the formation mechanism of the amorphous carbon nanotubes was also proposed accordingly.