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采用FeSO4-H2O2体系对碳纳米管氧化修饰的同时,氢氧化铁被吸附在碳纳米管管壁上,然后分别通过氢气、氮气、空气在723K下处理2h,制备了碳纳米管负载的γ-Fe2O3催化剂、γ-Fe2O3和α-Fe2O3复合催化剂和非晶态Fe2O3催化剂。采用XRD、TEM和TG-DSC表征了催化剂结构,采用连续流动乙苯气相脱氢生成苯乙烯反应对催化剂性能进行评价,结果表明:热处理条件对催化剂乙苯脱氢的催化性能影响明显,碳纳米管负载的晶态Fe2O3纳米催化剂对乙苯脱氢具有高的活性与选择性。 相似文献
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碳纳米管催化二硝酰胺铵燃烧和热分解 总被引:2,自引:0,他引:2
通过燃速测定和热失重研究了碳纳米管(CNTs)、CNTs负载Fe2O3纳米粒子(Fe2O3/CNT)和CNTs负载Fe.Cu纳米粒子(Fe.Cu/CNT)对二硝酰胺铵(ADN)燃烧和热分解的影响。结果表明:CNTs、Fe2O3/CNT和Fe.Cu/CNT三种催化剂都可以提高ADN的燃速,降低压力指数。当这三种催化剂添加质量分数为3%时,在4M Pa下,燃速从30.49mm/s分别增加到50.59mm/s、39.72mm/s和38.79mm/s,压力指数从0.81分别降低到0.36、0.67和0.75。TG分析表明,添加质量分数为1%催化剂时,这三种催化剂降低ADN的初始热分解温度分别为18.3℃、12.1℃和11.6℃。 相似文献
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纳米Fe2O3对聚氨酯/聚偏氟乙烯复合涂层摩擦学性能的影响 总被引:1,自引:0,他引:1
利用M-2000型摩擦磨损试验机考察了干滑动下纳米Fe2O3改性的聚氨酯/聚偏氟乙烯(PU/PVDF)复合涂层的摩擦磨损性能。采用扫描电子显微镜分析了纳米Fe2O3在复合涂层中的分布以及涂层的磨损表面。结果显示纳米Fe2O3在涂层中分布比较均匀,少量的纳米Fe2O3的加入不仅降低了聚氨酯/聚偏氟乙烯复合涂层的摩擦系数,而且还提高了聚氨酯/聚偏氟乙烯复合涂层的抗磨性。负载对复合涂层的摩擦磨损性能有较大的影响,随着负载的增加,涂层的磨损率升高。 相似文献
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采用浸渍法制备用于常温常压下催化湿式过氧化氢氧化工艺(CWPO)的负载型Fe2O3/γ-Al2O3催化剂,采用BET,SEM,XRD,XPS和XRF对其进行了表征,并以偶氮染料酸性橙为特征污染物,考察了Fe2O3/γ-Al2O3催化剂的催化活性和稳定性.研究表明,Fe2O3/γ-Al2O3催化剂中的活性组分Fe是以α-Fe2O3的形式存在,且Fe的负载量为1.907%(质量分数).对于初始浓度为500mg/L的酸性橙模拟废水,当Fe2O3/γ-Al2O3催化剂和H2O2氧化剂的投加量分别为30g/L和330mg/L时,处理3h时染料的脱色率、COD去除率和TOC去除率可分别达到82.10%,80.14%和74.2%.与传统Fenton试剂法相比,以Fe2O3/γ-Al2O3为催化剂的CWPO工艺具有矿化程度高和催化剂易回收再用的优点. 相似文献
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以丙烯酰胺为单体,采用原位聚合法制备了Fe3O4/聚丙烯酰胺纳米磁粒(Fe3O4/PAM);利用胺基与金的相互作用,借助自组装法在Fe3O4/PAM表面组装金胶体制备了草莓型纳米金磁颗粒(Fe3O4/PAM/Au);用TEM、VSM、UV-vis对其进行了表征,并考察了表面修饰核酸探针的金磁颗粒对核酸靶分子的分离能力。结果表明,Fe3O4/PAM/Au粒子的粒径为36~56nm,具有超顺磁性,饱和磁化强度为31.2emu/g,分散在磷酸盐缓冲液中的Fe3O4/PAM/Au完全磁分离的时间为6min。修饰核酸探针的Fe3O4/PAM/Au粒子可以借助核酸杂交作用分离核酸靶分子,分离能力为118pmol/mg。 相似文献
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首先通过化学共沉淀法制备出Fe3O4磁性纳米颗粒,考察了表面活性剂的用量、碱的用量、陈化时间以及三价铁与二价铁的摩尔比等因素对Fe3O4纳米颗粒性能的影响。制备出饱和磁化强度为73.85A.m2/kg、粒径大小为10nm以下的Fe3O4纳米颗粒。在此基础上,制备出Fe3O4/Au复合纳米颗粒,通过VSM、TEM、XRD、XPS对产物进行了表征,研究了HAuCl4的用量、还原剂的种类、硅烷偶联剂以及包金之前的Fe3O4纳米颗粒对复合颗粒的影响,结果表明所制得的Fe3O4/Au复合磁性纳米颗粒包覆良好,粒径大小为50~200nm,饱和磁化强度为10.08A.m2/kg。 相似文献
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采用沉淀方法制备了直径分布狭窄的均匀Fe3O4纳米颗粒.Fe3O4纳粒形体几近一致,平均粒径为10.33 nm±2.99 nm(平均粒径±标准偏差).在超声作用下将MgO纳米颗粒分散在一定量Fe3O4纳米颗粒的水溶液中获得MgO负载Fe3O4的纳米颗粒.以甲烷为碳源,Fe3O4/MgO为催化剂,经化学气相沉积,在Fe3O4纳粒上制得了大量直径近乎均匀的单壁碳纳米管(SWCNTs)束.TEM显示:SWCNTs的平均直径1.22rm.热重分析显示:样品在400℃~600℃温度区间失重量约19%.拉曼光谱显示:SWCNTs的ID/IG的强度比为0.03,表明采用Fe3O4/MgO催化剂可制得高石墨化程度的单壁碳纳米管. 相似文献
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为实现低变质煤资源化的目标,在低变质煤微波热解的基础上采用超声浸渍-焙烧法制备负载型Fe2O3/γ-Al2O3催化剂,采用场发射扫描电镜(SEM)及X射线能谱(EDS)对催化剂进行表征,研究了其对煤微波热解过程中的催化效果及机理,考察焙烧时间、焙烧温度等因素对催化剂催化活性的影响,通过气-质联用(GC-MS)及煤气分析仪对焦油及气体组分和含量进行测定。结果表明,Fe2O3/γ-Al2O3催化剂的加入提高了煤微波热解制氢气及焦油产率,超声浸渍条件下400℃焙烧4h制备的产品催化活性最佳。 相似文献
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Dechlorination of trichloroethylene in aqueous solution by noble metal-modified iron 总被引:6,自引:0,他引:6
Bimetallic particles are extremely interesting in accelerating the dechlorination of chlorinated organics. Four noble metals (Pd, Pt, Ru and Au), separately deposited onto the iron surface through a spontaneous redox process, promoted the TCE dechlorination rate, and the catalytic activity of the noble metal followed the order of Pd>Ru>Pt>Au. This order was found to be dependent on the concentrations of adsorbed atomic hydrogen, indicating that the initial reaction was cathodically controlled. Little difference in the distribution of the chlorinated products for the four catalysts (cis-DCE: 51%; 1,1-DCE: 27%; trans-DCE: 15% and VC: 7%) was observed. The chlorinated by-products accumulated in both Pt/Fe and Au/Fe (10.3% and 2.5% of the transformed TCE, respectively), but did not accumulate in Pd/Fe and Ru/Fe. Ru/Fe was further examined as an economical alternative to Pd/Fe. The 1.5% Ru/Fe was found to completely degrade TCE within 80 min. Considering the expense, the yield of chlorinated products and the lifetime of a reductive material, Ru provides a potential alternative to Pd as a catalyst in practical applications. 相似文献
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采用射频等离子体增强化学气相沉积(RF-PECVD)技术,以Ni为催化剂,经600℃裂解C2H2在Si基底上制备出定向碳纳米管薄膜。采用扫描电子显微镜(SEM)表征了刻蚀后Ni颗粒与沉积的碳纳米管薄膜的形貌。研究了辅助气体对等离子体预处理催化剂与碳纳米管生长的影响。结果表明:辅助气体(H2与N2)流量比对催化剂颗粒尺寸、分布以及碳纳米管生长有显著影响;合适的气体流量比有利于减少碳纳米管薄膜的杂质颗粒,促进其定向生长。预处理过程中气体流量比H2:N2=20:5时,预处理后催化剂Ni颗粒分布密度大、粒径小且分布范围窄,适合碳纳米管均匀着床;沉积生长碳纳米管薄膜时,H2:N2=20:15可得到纯度高、定向性好的碳纳米管。 相似文献
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《材料科学技术学报》2020,(3)
Approaches for the fabrication of a low power-operable formaldehyde(HCHO) gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide(In_2O_3) nanofibers decorated with well-dispersed Au nanoparticles as a sensing material.Homogeneous In_2O_3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process. Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In_2O_3 nanofibers. The Au-decorated In_2O_3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes.The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system(MEMS) technique. The micro-platform gas sensor consisting with Au-In_2O_3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity. The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration,the size of the adsorbed Au nanoparticles, the applied power to raise the temperature of a sensing part and the kind of target gases. 相似文献
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Ateyya A. Aboul-Enein Ahmed E. Awadallah Adel A.-H. Abdel-Rahman Ahmed M. Haggar 《Fullerenes, Nanotubes and Carbon Nanostructures》2018,26(7):443-450
The pyrolysis of different plastic waste types such as low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET) and polystyrene (PS) for producing multi-walled carbon nanotubes (MWCNTs) using a two-stage process has been investigated. Firstly, the cracking of plastic wastes was carried out at a temperature of 700°C to produce hydrocarbon gases. In the second stage, the produced hydrocarbon gases were decomposed at 650°C on the surface of the Ni-Mo/Al2O3 catalyst to form CNTs. Various analytical tools such as XRD, TPR, TGA, Raman spectroscopy and TEM were used to describe both the fresh catalyst and the obtained CNTs. The results showed that the amount of the hydrocarbon gases was related to the type of plastic waste and hence the CNT yield. Accordingly, LDPE or PP was decomposed to produce the largest gases yield of 72.5 or 70.7 wt%, respectively. As a result, a large CNTs yield of 5.8 and 5 g/gcat can be achieved by pyrolysis of PP and LDPE waste, respectively. However, a small yield of CNTs with little quality and low purity was obtained by using PS or PET waste as the carbon feedstock. 相似文献
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Yamada T Namai T Hata K Futaba DN Mizuno K Fan J Yudasaka M Yumura M Iijima S 《Nature nanotechnology》2006,1(2):131-136
We have succeeded in synthesizing vertically aligned doubled-walled carbon nanotube (DWNT) forests with heights of up to 2.2 mm by water-assisted chemical vapour deposition (CVD). We achieved 85% selectivity of DWNTs through a semi-empirical analysis of the relationships between the tube type and mean diameter and between the mean diameter and the film thickness of sputtered Fe, which was used here as a catalyst. Accordingly, catalysts were engineered for optimum DWNT selectivity by precisely controlling the Fe film thickness. The high efficiency of water-assisted CVD enabled the synthesis of nearly catalyst-free DWNT forests with a carbon purity of 99.95%, which could be templated into organized structures from lithographically patterned catalyst islands. 相似文献
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CO combustion catalysts of Au loaded on Co3O4 which contains high concentration of Au (3, 10, 20, and 40 wt%) for the integration on the microdevice were developed and
the combustion performance of these catalysts were evaluated. The highly dispersed Au/Co3O4 catalyst was prepared using the mechanical mixing of the Au colloid (average particle size of 3 nm) and a cobalt oxide powder
(particle size of 20–30 nm). The catalyst preparation by the colloid process could result a better dispersion of Au particles
in the Au/Co3O4 catalyst. The Au particle size of the Au content of 20 wt% was 1/10 of that by the catalyst of same composition prepared
by impregnation process in our previous studies. This improvement of microstructure enhanced the combustion performance of
the catalyst, which was improved 10 times as compared to that of our previous study. Moreover, the CO selectivity of the Au/Co3O4 catalyst on the microdevice depended on the Au particle size. 相似文献
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以聚二甲基二烯丙基氯化铵功能化石墨烯(PDDA-GNs)和磷钼酸功能化石墨烯(PMo12-GNs)为原料,利用层层自组装法制备了功能化石墨烯多层膜({PDDA-GNs/PMo12-GNs}),以此多层膜为载体,通过恒电位电沉积法制备功能化石墨烯多层膜载金催化剂(Au/{PDDA-GNs/PMo12-GNs}n)。采用XRD、XPS和SEM等表征Au/{PDDA-GNs/PMo12-GNs}n催化剂的组成、结构和形貌。结果表明:实验成功制备了Au/{PDDA-GNs/PMo12-GNs}n催化剂,且多层膜载体改善了Au粒子的分散性。利用循环伏安(CV)、计时电流(It)和交流阻抗(EIS)等评价催化剂对肼氧化的电催化性能。结果表明,Au/{PDDA-GNs/PMo12-GNs}n催化剂使肼氧化的电催化活性和稳定性得到很大提高。与Au/玻碳电极(GCE)相比,Au/{PDDA-GNs/PMo12-GNs}n催化肼氧化反应的峰电流密度从0.46 mA/cm2提高到0.87 mA/cm2,600 s时的稳态电流密度是Au/GCE的2.5倍。 相似文献