共查询到19条相似文献,搜索用时 62 毫秒
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超增溶自组装原位合成ZSM-5纳米分子筛 总被引:1,自引:0,他引:1
采用超增溶胶团法制备纳米ZSM-5分子筛。考察体系水含量、乳化剂用量、晶化温度和焙烧温度等因素对合成分子筛产品的粒径、晶体形貌、孔径、孔容和比表面积等的影响,并采用BET、XRD和TEM等手段对其进行表征。结果表明,制备纳米ZSM-5分子筛的最佳条件:n(H2O)∶n(SiO2)=90,乳化剂(RHP)质量分数为10%,晶化温度180 ℃,焙烧温度500 ℃。制得的粒子平均粒径(50~70) nm,大多数粒子为球形,粒径分布较窄,呈单分散且微粒不易团聚。 相似文献
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超增溶胶团自组装原位制备单分散纳米TiO2 总被引:1,自引:0,他引:1
以四氯化钛为原料,应用自制模板剂,采用超增溶胶团自组装原理制备TiO2纳米微粒,利用XRD、TEM和BET吸附等分析测试手段对所得TiO2微粒的晶相组成、粒径大小和形貌进行表征,表明制备的锐钛矿型TiO2纳米微粒具有较好的分散性,一次粒径大小为8~16 nm,二次粒径80~120 nm。 相似文献
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溶胶-水热合成法制备纳米4A分子筛 总被引:1,自引:0,他引:1
以磷肥行业副产的含氟硅胶为原料,采用溶胶-水热合成法成功制备纳米4A分子筛,并采用XRD、SEM、激光粒度分析等手段与常规水热合成的4A分子筛进行了对比。结果表明,纳米4A分子筛钙交换容量为325mg/g,白度为95%,可满足洗涤助剂的要求。 相似文献
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在表面活性剂聚乙二醇(PEG)、聚丙烯酸钠(PAAS)、聚乙烯醇(PVA)的辅助下,采用溶胶-凝胶法制备了一系列掺Ba纳米MgO及其负载的氨合成Ru催化剂。并采用场发射扫描电镜、X射线粉末衍射、N2物理吸附-脱附、X射线能谱仪对样品进行表征。结果表明:表面活性剂的添加可改善掺Ba纳米MgO的织构性质和表面性质,并增强钡、镁之间的相互作用,促使了钡在载体中的分散。其中,在10 MPa、425 ℃、10000 h-1的测试条件下,添加5%的PAAS时制得的2%Ru/Ba-MgO催化剂出口氨生成速率达65.9 mmol/(g?h)。 相似文献
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Gunjan Verma K.C. Barick N. Manoj A.K. Sahu P.A. Hassan 《Ceramics International》2013,39(8):8995-9002
Use of macromolecular templates for controlling nanostructures of inorganic materials is an active area of research. In particular, oriented growth of hydroxyapatite in organic matrix is of great relevance to understand biomineralisation of bone and its potential biomedical applications. Natural bone being a composite of hydroxyapatite and collagen fibers, crystallization of hydroxyapatite in fibrous assemblies could mimic such biomineralisation. This motivated us to investigate the role of long rod-like micelles in modulating the structure of hydroxyapatite particles. In this article, we report the preparation of porous hydroxyapatite nanorods using rod-like micelles made up of a cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic hydrotrope sodium salicylate (SS) as a templating agent. The successful formation of hydroxyapatite crystals is evident from XRD, FTIR, TGA, SEM and TEM analyses. It has been observed that large hydroxyapatite nanorods of diameter ~50 nm are formed in surfactant mediated synthesis, whereas irregular shaped nanoaggregates of hydroxyapatite are obtained in the absence of surfactant. A comparative study on the porosity of hydroxyapatite clearly shows that monomodal distribution of mesopores with a peak at ~30 nm in the absence of surfactant while bimodal distribution of mesopores having maxima at ~4 nm and ~45 nm appear in hydroxyapatite prepared in the presence of surfactant template. 相似文献
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Macroporous poly(styrene-divinyl benzene) microspheres with pore size of about 500 nm were prepared by a new method, surfactant reverse micelles swelling method. The macroporous microspheres were prepared by convenient suspension polymerization. The difference from conventional suspension polymerization was that a higher concentration of surfactant was added in the oil phase. The effects of the amount and type of surfactants on the morphology of microspheres were investigated, and the formation mechanism was also discussed. Macropores were formed when the concentration of surfactant was much higher than critical micelle concentration (cmc). It was proposed that a large amount of reverse micelles formed by adding a large amount of surfactant in the oil droplet phase, and the reverse micelles could absorb water from the external aqueous phase. The water in the oil phase formed macropores after polymerization. The method developed in this study was convenient to prepare microspheres with larger pore size than the conventional method such as agglomeration method of nanoparticles. 相似文献
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Huijie Cheng Yali Li Edwin Kroke Stefanei Herkenhoff 《Journal of the European Ceramic Society》2013,33(11):2181-2189
In situ synthesis of Si2N2O/Si3N4 composite ceramics was conducted via thermolysis of novel polysilyloxycarbodiimide ([SiOSi(NCN)3]n) precursors between 1000 and 1500 °C in nitrogen atmosphere. The relative structures of Si2N2O/Si3N4 composite ceramics were explained by the structural evolution observed by electron energy-loss spectroscopy but also by Fourier transform infrared and 29Si-NMR spectrometry. An amorphous single-phase Si2N2O ceramic with porous structure with pore size of 10–20 μm in diameter was obtained via a pyrolyzed process at 1000 °C. After heat-treatment at 1400 °C, a composite ceramic was obtained composed of 53.2 wt.% Si2N2O and 46.8 wt.% Si3N4 phases. The amount of Si2N2O phase in the composite ceramic decreased further after heat-treatment at 1500 °C and a crystalline product containing 12.8 wt.% Si2N2O and 87.2 wt.% Si3N4 phases was obtained. In addition, it is interesting that residual carbon in the ceramic composite nearly disappeared and no SiC phase was observed in the final Si2N2O/Si3N4 composite. 相似文献
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ZSM-5 zeolite has been hydrothermally synthesized in-situ on the external surface of calcined kaolinite in the presence of n-butylamine. This supported zeolite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and N2 adsorption. Several synthesis variables were systematically investigated, including SiO2 to Al2O3 ratio, pH, crystallization time, and crystallization temperature. After mixing the ZSM-5 with a Fluid Catalytic Cracking (FCC) catalyst, catalytic performance was evaluated by cracking vacuum gas oil (VGO) in a micro-fixed bed reactor. ZSM-5 addition was favorable for the production of light olefins by catalytic cracking of VGO. 相似文献
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探讨采用微波辅助合成尾式卟啉(p-BrTMOPP)的制备工艺及其影响因素。以吡咯、对羟基苯甲醛和对甲氧基苯甲醛为原料,以丙酸为溶剂,制备得到p-HTMOPP;以1,4-二溴丁烷为原料,微波辅助加热条件下制备得到目标化合物尾式卟啉p-BrTMOPP;目标产物经过UV-vis、IR、ESI-MS等方法表征。在90℃、DMF溶剂条件下微波辐射加热30min,快速高效得到目标化合物,反应产率89.2%。和传统加热方法相比较,微波辅助合成尾式卟啉化合物明显缩短了反应时间,提高了反应效率。 相似文献
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4A沸石合成工艺研究与产物表征 总被引:1,自引:0,他引:1
利用正交优选实验研究了硅铝比、钠硅比、水钠比、反应温度和反应时间等5个因素对水热合成4A沸石的影响,在此基础上还研究了超声波辅助水热合成4A沸石,利用XRD、场发射扫描电子显微镜(FESEM)和钙离子交换能力对4A沸石进行了表征。正交优选实验结果表明:硅铝比是影响4A沸石钙离子交换能力的主要因素,其次是钠硅比和反应时间,水钠比和反应温度的影响最小;水热合成4A沸石的最佳工艺为以硅铝物质的量比为1.5、钠硅物质的量比为2.05、水钠物质的量比为150配制硅铝酸钠凝胶,于130℃下晶化5 h。通过水热合成及超声波辅助水热合成的4A沸石的对比表明:一定时间的超声波辅助水热合成更容易得到较高性能的4A沸石。 相似文献