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991.
《Surface and interface analysis : SIA》2018,50(3):393-398
In this communication, we report a new, simple, and eco‐friendly method to develop highly dispersible multiwalled carbon nanotubes (MWCNTs) by π‐π stacking and azide‐grafting. MWCNTs were functionalized via standard physisorption, followed by nitrene addition using azido compounds upon ultraviolet activation. The functionalized MWCNTs show excellent dispersibility without raising distinct damage, which can bear comparison with that of MWCNTs oxidized with mixture acids. This method allows for the improvement of the chemical compatibility of MWCNTs with specific polymers for application in nanotube‐based composites and opens a potential pathway for surface protection. 相似文献
992.
建立了一种以多壁碳纳米管(MWCNTs)为分散固相萃取吸附剂的前处理净化技术,结合在线凝胶色谱/气相色谱-三重四极杆串联质谱(GPC/GC-MS/MS)同时测定茶叶中40种有机磷农药残留的方法。茶叶用乙腈提取,经MWCNTs净化后进行GPC/GC-MS/MS分析。利用该方法对空白茶叶样品进行20、50、150μg/kg 3个不同浓度水平的加标回收试验,平均回收率为84.2%~109.9%,相对标准偏差(RSD,n=6)不大于8.9%,方法检出限为0.5~4.6μg/kg。该方法快速简便、灵敏度高、成本低,可以满足多种农药残留同时分析的要求。 相似文献
993.
Zirconium–Porphyrin‐Based Metal–Organic Framework Hollow Nanotubes for Immobilization of Noble‐Metal Single Atoms 下载免费PDF全文
Ting He Dr. Shuangming Chen Bing Ni Yue Gong Zhao Wu Prof. Li Song Prof. Lin Gu Prof. Wenping Hu Prof. Xun Wang 《Angewandte Chemie (International ed. in English)》2018,57(13):3493-3498
Single atoms immobilized on metal–organic frameworks (MOFs) with unique nanostructures have drawn tremendous attention in the application of catalysis but remain a great challenge. Various single noble‐metal atoms have now been successfully anchored on the well‐defined anchoring sites of the zirconium porphyrin MOF hollow nanotubes, which are probed by aberration‐corrected scanning transmission electron microscopy and synchrotron‐radiation‐based X‐ray absorption fine‐structure spectroscopy. Owing to the hollow structure and excellent photoelectrochemical performance, the HNTM‐Ir/Pt exhibits outstanding catalytic activity in the visible‐light photocatalytic H2 evolution via water splitting. The single atom immobilized on MOFs with hollow structures are expected to pave the way to expand the potential applications of MOFs. 相似文献
994.
995.
In order to improve the heat transfer process by using nanofluids, different nanoparticles and base fluids have been studied. In this work, stability and effect of aging and temperature on the thermal conductivity of CNTs-ethylene glycol (EG) nanofluids were investigated. Chemical functionalisation was used to oxidise the surface of CNTs. The functionalised CNTs were used to prepare the nanofluids by a two-step method. The stability of nanofluids was measured by UV-vis spectroscopy and the results showed that the nanofluids had a good stability over several days. Immediately after nanofluid preparation not too much increase was observed for thermal conductivity but the nanofluid aging had a great influence on the improvement of the thermal conductivity, as after 65 days, about 50% increase was observed. The increase has been attributed to forming an ordered nanolayer of EG molecules around the CNTs. Also no significant temperature dependence of thermal conductivity was observed up to 50°C possibly due to the lack of temperature dependence of CNTs Brownian motions. 相似文献
996.
A. N. Samoilov S. S. Minenko L. N. Lisetski M. S. Soskin S. I. Torgova 《Liquid crystals》2018,45(2):250-261
Optical transmission and selective reflection data are reported for suspensions of single-walled carbon nanotubes (CNTs) in photoactive nematic material ZhK-440 with a mesogenic chiral dopant M5. At small concentrations of CNTs (C ≈ 0.01–0.05%), the preferential localisation of CNTs at oily sticks (cholesteric topological defects) and suppression of the network of oily streaks by CNTs were observed. At the same time, the optical density D was shown to be essentially non-linear and a minimum at certain concentration of CNTs, C ≈ 0.05–0.08%, was observed. This anomalous behaviour was explained by the presence of the structural transition from the loose (ramified) aggregates with highly anisotropic shape (oriented along the anchoring direction on rubbed polyvinyl alcohol) to the compact aggregates with denser packing. The location of this minimum, as well as the selective reflection maximum (helical pitch), was sensitive to partially reversible UV-induced trans–cis–trans isomerisation effects. The UV-controlled helical pitch variation was shown to be only slightly affected by introduction of CNTs. 相似文献
997.
A new method for multi-component synthesis of 1,4-dihydropyridine derivatives (1,4-DHPs) in the presence of meglumine supported on multiwalled carbon nanotubes (MWCNTs@meglumine) as a new heterogeneous, highly efficient and reusable catalyst was investigated. The reaction was performed under ultrasonic irradiation in EtOH at room temperature. A new, highly efficient heterogeneous catalyst, short reaction times, high to excellent yield of products, and safe and clean conditions are the advantages of the presented method. 相似文献
998.
Jingming Gong Lianyi Wang Kun Zhao Dandan Song Lizhi Zhang 《Electrochemistry communications》2008,10(9):1222-1225
A novel hybrid bifunctional sensing platform for simultaneous determination of NO and O2 has been developed, whereby hematite nanotubes are immobilized into the chitosan matrix onto a gold electrode (labeled as HeNTs-Chi/Au). The HeNTs distributed in porous-structured chitosan matrix not only offer abundant active sites for bifunctional sensing of NO and O2, but also facilitate oxidation of NO and reduction of O2 dramatically. Straight calibration curves are achieved in analyte concentration ranges of 5.0 × 10−8 to 1.25 × 10−6 mol L−1 for NO and 2.5 × 10−7 to 6.0 × 10−6 mol L−1 for O2. Also, the detection limits are low of 8.0 × 10−9 mol L−1 for NO and 5.0 × 10−8 mol L−1 for O2. Such an efficient bifunctional sensor for NO and O2 offers great potential in quantitation of NO levels in biological and medical systems, since NO level is highly regulated by various reactive oxygen species. 相似文献
999.
Platinum nanoparticles were successfully deposited within a multiwalled carbon nanotube (MWCNT)–Nafion matrix by a cyclic
voltammetry method. A Pt(IV) complex was reduced to platinum nanoparticles on the surface of MWCNTs. The resulting Pt nanoparticles
were characterized by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy.
The Pt–MWCNT–Nafion nanocomposite film-modified glassy carbon electrode had a sharp hydrogen desorption peak at about −0.2 V
vs. Ag/AgCl (3 M) in a solution of 0.5 M H2SO4, which is directly related to the electrochemical activity of the Pt nanoparticles presented on the surface of MWCNTs. The
electrocatalytic properties of the Pt–MWCNT–Nafion nanocomposite-modified glassy carbon electrode for methanol electrooxidation
were investigated by cyclic voltammetry in a 2 M CH3OH + 1 M H2SO4 solution. In comparison with the Pt-coated glassy carbon electrode and the Pt–Nafion modified glassy carbon electrode, the
Pt–MWCNT–Nafion-modified electrode had excellent electrocatalytic activity toward methanol electrooxidation. The stability
of the Pt–MWCNT–Nafion nanocomposite-modified electrode had also been evaluated. 相似文献
1000.