埃洛石纳米管在分离富集中的应用

埃洛石纳米管(Halloysite Nanotubes,HNTs)是一种天然的纳米管状材料,具有对环境友好、生物相容性好、细胞毒性小等特点,近年来该材料得到了广泛的应用。HNTs是生物相容性较好的"绿色"材料,成本低、来源广等优点使其成为制备生物复合材料中的添加剂,而且HNTs具有的空腔结构、表面电荷性质及表面吸附性为重金属离子、染料分子、有机分子等的分离富集提供有利条件。另外,HNTs及其衍生的生物复合材料在循环肿瘤细胞的富集上得到应用。为了更好地了解和利用埃洛石纳米管,本文介绍了埃洛石纳米管的物理化学性能,以及HNTs在分离富集、活性分子的载运与控制释放等方面的应用进展,并对埃洛石纳米管的发展及应用前景进行展望。     

埃洛石表面修饰并负载salen钼高效催化烯烃环氧化反应

采用温和的化学表面改性和自组装方法成功制备了埃洛石纳米管负载salen钼(HNTs-SL-Mo)催化剂,运用透射电镜、X射线衍射、红外光谱、诱导偶合等离子体谱和X射线光电子能谱表征了催化剂的形态、大小和分散性等性质。结果证明了salen结构的存在和埃洛石配位钼催化剂的成功制备。制备的催化剂在各种烯烃的环氧化反应中均有很好的活性,且活性高于均相催化剂。对比实验表明,在固定MoO(O2)2(DMF)2时, salen结构发挥了重要作用,不能用N原子作为单一配体来代替。本文还推测了钼和salen配体可能的连接方式和该催化剂催化烯烃环氧化反应的机理。该催化剂在重复使用8次后其活性未见明显下降,表现出优异的重复使用性能。由于埃洛石是一种廉价易得的材料,因此它可为设计效果独特的催化剂提供一个选择。     

埃洛石表面修饰并负载salen钼高效催化烯烃环氧化反应

采用温和的化学表面改性和自组装方法成功制备了埃洛石纳米管负载salen钼(HNTs-SL-Mo)催化剂，运用透射电镜、X射线衍射、红外光谱、诱导偶合等离子体谱和X射线光电子能谱表征了催化剂的形态、大小和分散性等性质。结果证明了salen结构的存在和埃洛石配位钼催化剂的成功制备。制备的催化剂在各种烯烃的环氧化反应中均有很好的活性，且活性高于均相催化剂。对比实验表明，在固定MoO(O2)2(DMF)2时， salen结构发挥了重要作用，不能用N原子作为单一配体来代替。本文还推测了钼和salen配体可能的连接方式和该催化剂催化烯烃环氧化反应的机理。该催化剂在重复使用8次后其活性未见明显下降，表现出优异的重复使用性能。由于埃洛石是一种廉价易得的材料，因此它可为设计效果独特的催化剂提供一个选择。     

埃洛石纳米管的改性方式对其负载的金催化剂在环己烷液相选择性氧化反应中的催化性能的影响

为了提高纳米金在埃洛石纳米管(halloysite nanotubes,HNTs)上的负载率并改善负载型金催化剂的稳定性,采用经过有机硅烷(N-(β-氨乙基)-γ-氨丙基三甲氧基硅烷,AEAPTMS)化学改性的埃洛石纳米管(AHNTs)作为载体,利用AEAPTMS上的-NH2能够配位俘获金离子的特点,实现了金的前驱体H...     

直接甲醇燃料电池Pt基阳极催化剂的研究进展

作为未来能源储存和转换装置的理想选择, 直接甲醇燃料电池具有能量密度高、携带方便以及环境友好等特点. 直接甲醇燃料电池欲实现商业化关键在于如何降低其催化剂成本, 构建高效稳定催化层, 尤其是阳极催化层. 由于非Pt催化剂对于甲醇催化氧化效率太低, 远远达不到商业化应用的要求, 因此对于Pt基改性催化剂的研究具有更重要的现实意义. 对于催化剂而言, 其微观电子结构以及能级密度分布很大程度上决定着催化剂的本征催化活性. 因此通过对其宏观特性的调控以改变Pt的微观结构, 是提高Pt基催化剂催化活性的有力方向. 本文着重从催化剂的组成、形貌和粒度等方面就近几年对Pt基催化剂的改性研究进行了综述, 并对其改性机理进行了相关讨论.     

埃洛石表面修饰并负载salen钼高效催化烯烃环氧化反应（英文）

采用温和的化学表面改性和自组装方法成功制备了埃洛石纳米管负载salen钼(HNTs-SL-Mo)催化剂,运用透射电镜、X射线衍射、红外光谱、诱导偶合等离子体谱和X射线光电子能谱表征了催化剂的形态、大小和分散性等性质.结果证明了salen结构的存在和埃洛石配位钼催化剂的成功制备.制备的催化剂在各种烯烃的环氧化反应中均有很好的活性,且活性高于均相催化剂.对比实验表明,在固定Mo O(O2)2(DMF)2时,salen结构发挥了重要作用,不能用N原子作为单一配体来代替.本文还推测了钼和salen配体可能的连接方式和该催化剂催化烯烃环氧化反应的机理.该催化剂在重复使用8次后其活性未见明显下降,表现出优异的重复使用性能.由于埃洛石是一种廉价易得的材料,因此它可为设计效果独特的催化剂提供一个选择.     

Pt-skin的Pt基双金属电催化的氧还原设计

过去几十年,能源储存转化领域取得重大的进展. 而Pt-skin的Pt基双金属电催化剂在调控电催化剂的电子结构具有巨大的前景,特别是对于氧还原反应而言. 本工作主要综述了最近几年关于Pt-skin的Pt 基双金属电催化剂的设计制备,以及其性能. 本文的主要重点在于系统的综述了Pt-skin的Pt 基双金属电催化剂的合成方法,以及其对于氧还原反应的机理研究.     

MXene基单原子催化剂的制备及其在电催化中的应用

单原子催化剂具有高原子利用率、高催化活性和高选择性等优点,兼具了均相催化剂“独立活性位点”和非均相催化剂“易循环利用”的特点,有效解决贵金属昂贵稀少的缺陷。其中载体不仅能影响单原子的稳定性,还影响其电子结构,从而影响催化性能。作为一种新型二维无机材料,MXene具有比表面积大、带隙可调、导电性好和螯合位丰富等特点,是制备单原子催化剂的理想载体材料。本文简要总结了MXene的结构特点,综述了MXene基单原子催化剂的制备策略,并着重介绍了MXene基单原子催化剂在电化学能源转换领域的应用,包括析氢反应、氧电极反应、氮还原反应、二氧化碳还原反应,以及在电池储能方面的应用。最后,总结了当前MXene基单原子催化剂在研究和实用方面所面临的挑战与机遇。     

Pd基催化剂在分解甲酸析氢中的研究进展

甲酸是最简单的羧酸,无色、低毒,在室温下便于运输和储存。最近,甲酸作为一种最有前景的储氢材料,在室温下采用异相催化剂分解甲酸制氢气引起了科研工作者的广泛关注。和其他催化剂相比,Pd基催化剂在温和条件下催化甲酸分解制备氢气方面表现出优良的性能,是一种非常理想的非均相催化剂。本文介绍了多种Pd基催化剂的性能特点、制备方法和其在催化甲酸分解制备氢气领域的研究进展,并对其未来研究发展方向进行展望。     

直接甲醇燃料电池催化剂的制备与表征综合化学实验

将学科前沿领域的科研成果转化为研究型综合实验，结合新清洁能源发展介绍了直接甲醇燃料电池催化剂的制备与表征。采用液相还原取代法制备铂纳米管，通过XRD、TEM、XPS对材料进行形貌和结构表征，并以氢氧化钾溶液为电解质测试铂纳米管催化剂的电化学性能。通过开设该实验，不仅让学生了解直接甲醇燃料电池关键催化剂制备的实验原理、合成方法及数据分析，还可以更好地锻炼学生综合实验的操作技能，在培养研究兴趣的同时提升创新思维和创新能力。     

改性埃洛石材料的制备及其对亚甲基蓝吸附行为的研究

使用硅烷偶联剂KH550改性埃洛石纳米管获得改性材料HNTs-APTS,并对其吸附亚甲基蓝的行为进行研究。利用傅立叶变换红外光谱仪(FTIR)、X-衍射仪(XRD)对改性前后的埃洛石进行表征。考察了吸附时间和温度对吸附过程的影响,并采用Lagrange准二级动力学方程、Langmuir等温线方程及Freundlich等温线方程对实验数据进行拟合。结果表明,KH550成功负载到埃洛石表面;改性后材料的吸附能力大大提高。改性埃洛石对亚甲基蓝的吸附约在60 min达平衡,最大吸附容量为21.66 mg/g。其吸附过程符合准二级动力学方程,热力学较好地符合Langmuir等温线方程,且吸附过程为自发吸热,升高温度有利于吸附的进行。改性材料可重复再生6次,具有良好的再生性能,可在工业处理亚甲基蓝废水中使用。     

CuI‐functionalized halloysite nanoclay as an efficient heterogeneous catalyst for promoting click reactions: Combination of experimental and computational chemistry

Amine‐functionalized halloysite nanotubes (HNTs‐2 N) were prepared and further modified by introduction of salicylaldehyde and formation of imine functionality (HNTs‐2 N‐Sal). The latter was subsequently used for immobilization of CuI and formation of CuI@HNTs‐2 N‐Sal, which could effectively promote click reactions of terminal alkynes, sodium azide and α‐haloketones or alkyl halides in aqueous media and under mild reaction conditions to afford 1,2,3‐triazoles in relatively short reaction times. Notably, the catalyst could be recycled in up to six reaction runs with negligible loss of catalytic activity and CuI leaching. Also, the geometry of CuI adsorption on the modified HNTs surface was explored by molecular simulation with density functional theory. Furthermore, topographic steric maps of possible coordination modes were obtained using the recently released SambVca2 web application tool. Based on obtained results, a catalytic site with superior performance was suggested.     

Growth of carbon nanotubes on the novel FeCo-Al2O3 catalyst prepared by ultrasonic coprecipitation

FeCo-Al_2O_3 catalyst was prepared by an ultrasonic coprecipitation (UC) method for the growth of carbon nanotubes (CNTs) from catalytic decomposition of methane. Its catalytic performance was compared with that of the FeCo-Al_2O_3 catalyst counterparts prepared by stepwise impregnation (I) and conventional coprecipitation (C) methods, respectively. The structure and properties of the catalysts and the CNTs as produced thereon were investigated by means of XRD, XPS, TEM and N_2 adsorption techniques. It was found that the catalyst prepared by the ultrasonic coprecipitation method was more active, and the yield and purity of the synthesized CNTs were promoted evidently. The XPS results revealed that there were more active components on the surface of the catalyst prepared by the ultrasonic coprecipitation method. On the other hand, N_2 adsorption demonstrated that the catalyst prepared by the ultrasonic coprecipitation method conferred larger specific surface area, which was beneficial to dispersion of active components. TEM images further confirmed its higher dispersion. These factors could be responsible for its higher activity for the growth of CNTs from catalytic decomposition of methane.     

Enhanced removal efficiency of methyl red via the modification of halloysite nanotubes by copper oxide

Halloysite nanotubes (HNTs) were modified with CuO to form CuO-HNT composites. Results revealed that the CuO particles deposited on the HNT have higher specific surface area (S_BET) and pore volume compared to unmodified HNT. Application of the composites for the removal of methyl red (MR) dye was investigated. The composites have better removal efficiency than HNT. The data fitted the Freundlich adsorption isotherms. Kinetics of adsorption favored the pseudo-second-order model. Removal efficiency was faster and higher in alkaline conditions. Reusability experiments show that the low-cost composites were effective up to seven cycles.     

Synthesis and modification of multi-walled carbon nano-tubes (MWCNTs) for water treatment applications

Synthesis of MWCNTs by chemical vapor deposition (CVD) of acetylene is investigated at different temperatures. Fe-Co/CaCO₃ catalyst/support prepared by wet impregnation method is used. CaCO₃ was found to be a good support as a high selective material for deposition of CNTs with high purity. The effect of temperature on catalyst/support phases and crystal size was identified by using XRD. The crystallite size was decreased with increase temperature. The effect of growing time and temperature on carbon yield was studied and the deposited MWCNTs increased with temperature. The structure and purity of synthesized CNTs at different temperatures was examined by TEM and the effect of temperature on the surface area of the synthesized MWCNTs was investigated, the surface area decreased as the temperature increased. The prepared CNTs were purified using chemical oxidation method and the effect of acid treatment on CNTs surface was examined by TEM and SEM. The function groups produced at CNTs surface were investigated by using FTIR spectroscopy also the effect of CNTs preparation temperature on FTIR spectra was studied. The functionalized CNTs were used for adsorption of some heavy metals and for removal of some organic dyes from water.     

Cellulose–halloysite nanotube composite hydrogels for curcumin delivery

Halloysite nanotubes (HNTs) were added to cellulose NaOH/urea solution to prepare composite hydrogels using epichlorhydrine crosslinking at an elevated temperature. The shear viscosity, mechanical properties, microstructure, swelling properties, cytocompatibility, and drug delivery behavior of the cellulose/HNT composite hydrogels were investigated. The viscosity of the composite solution increases with the addition of HNT. The compressive mechanical properties of composite hydrogels are significantly improved compared with pure cellulose hydrogel. The compressive strength of the composite hydrogels with 66.7% HNTs is 128 kPa, while that of pure cellulose hydrogel is only 29.8 kPa in compressive strength. Rheological measurement suggests the resistance to deformation is improved for composite hydrogels. X-ray diffraction and Fourier transform infrared spectroscopy show that the crystal structure and chemical structure of HNT are not changed in the composite hydrogels. Hydrogen bonding interactions between HNT and cellulose exist in the composites. A porous structure of the composite hydrogels with pore size of 200–400 μm was found by scanning electron microscopy. The addition of HNT leads to decreased swelling ratios in NaCl solution and pure water for the composite hydrogels. Cytotoxicity assays show that the cellulose/HNT composite hydrogels have a good biocompatibility with MC3T3-E1 cells and MCF-7 cells. Curcumin is further loaded into the composite hydrogel via physical adsorption. The curcumin-loaded composite hydrogels show a strong inhibition effect on the cancer cells. All the results illustrate that the cellulose/HNT composite hydrogels have promising applications such as anticancer drug delivery systems and anti-inflammatory wound dressings.     

一维纳米炭/竹炭的制备及其对Pb~(2+)的吸附

以二甲苯为炭源、二茂铁为催化剂,采用CVD法在竹炭上催化气相生长了一维纳米炭,采用扫描电镜、透射电镜及氮吸附仪等对一维纳米炭/竹炭的形貌、微结构及比表面积进行了表征,并研究了一维纳米炭/竹炭复合材料对重金属离子Pb2+的吸附性能.结果表明,采用CVD法可以在竹炭上生长一维纳米炭,且随着气相生长时间的延长,竹炭上的一维纳米炭变得更加浓密而均匀.竹炭上生长一维纳米炭后,对Pb2+的吸附能力增强,硝酸氧化处理可以进一步提高一维纳米炭/竹炭对Pb2+的吸附能力.     

A Dual‐Surface Amidoximated Halloysite Nanotube for High‐Efficiency Economical Uranium Extraction from Seawater

By chemical cross‐linking the amidoxime group onto dual‐surfaces of natural ore materials, namely halloysite nanotubes (HNTs), an efficient adsorbent, AO‐HNTs, is developed. AO‐HNTs show high uranium adsorption capacity of 456.24 mg g^?1 in 32 ppm uranium‐spiked simulated seawater. In natural seawater, AO‐HNTs reach the high uranium extraction capacity of 9.01 mg g^?1 after 30 days’ field test. The dual‐surface amidoximated hollow nanotubular AO‐HNTs exhibit more coordination active sites for uranium adsorption, which is attributed to the high and fast uranium adsorption capacity. Because of the stable natural ore structure, AO‐HNTs also show long service life. Benefiting from the low cost of HNTs, the cost for uranium extraction from seawater is close to the uranium price in the spot uranium market, suggesting that AO‐HNTs could be used for economical extraction of uranium from the oceans.     

碳纳米管/半导体复合材料光催化研究进展

碳纳米管具有良好的机械性能和导电性、高化学稳定性、大表面积以及独特的一维结构,与半导体光催化剂结合能够增强催化剂的吸附能力、提高光催化效率、扩展光响应范围,而且有利于回收催化剂,极大地提高了半导体光催化剂的综合性能。本文首先分析了半导体光催化剂和碳纳米管的特点,总结了碳纳米管增强半导体光催化的机理,然后分别从复合材料制备方法、复合半导体种类和典型的应用三个不同角度,归纳总结了近年来碳纳米管/半导体复合材料光催化的研究进展,最后对其发展趋势作了展望。