共查询到18条相似文献,搜索用时 78 毫秒
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通过氧化-沉淀法合成了具有光催化活性的-αFeO(OH)纳米棒,用TGA、SEM、BET等分析方法进行结构表征和性能测试,并对其降解偶氮类染料的性能进行了研究。结果表明,产物主要成分为针铁矿-αFeO(OH),另含有少量Fe3O4;产物长径比较高,比表面积为32.89m2/g,并具有优良的磁性能。在作为光催化剂降解偶氮类染料甲基橙的实验中,-αFeO(OH)纳米棒表现出较好的催化效果。在21W、50W模拟光源和自然光照下降解3h以上,其脱色率分别为29.8%、43.5%和76.4%。 相似文献
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在不同工艺条件下采用沉淀法制备了低维纳米AlO(OH),并对样品进行了XRD、FT-IR及SEM表征分析。结果表明,pH值较低和较高时,样品的结晶度均较低。反应温度为75℃和95℃时,样品的结晶度均较好,无杂质。当pH值为9.0、反应温度为85℃时,样品中存在大量缔合-OH,AlO(OH)结晶度较好,且有少量Al(OH)3晶体存在。由于SDBS在Al(OH)3颗粒表面形成完整胶束,且有空间位阻效应,此时形成的样品为5nm厚、长宽可达100~300nm的边缘卷曲的蓬松片状物,形貌规则、尺寸均匀、分散性较好。 相似文献
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包覆纳米镍粒子的碳纳米管磁性研究(英文) 总被引:13,自引:8,他引:5
通过溶胶 -凝胶超临界干燥技术制备出NiO SiO2 比为 1.2的二元气凝胶纳米催化剂 ,并以气凝胶为催化剂通过化学气相热解法合成了碳纳米管 ;碳纳米管的合成是在石英管式炉中完成。将催化剂置于石英舟中 ,在流动氮气中将管式炉加热至所需的温度 ,然后通入甲烷、氢气混合气体 ,热解反应 30min~ 6 0min后形成碳纳米管。反应结束后 ,生成的碳纳米管在氮气氛中冷却至室温。采用XRD、SEM、TEM、HRTEM、Raman分析手段对制得的碳纳米管进行了表征 ,并测定其磁化系数。结果表明 :裂解产物主要由碳纳米管和纳米镍粒子组成 ,且纳米镍粒子包覆于碳纳米管的顶端。这种包覆纳米镍粒子的碳纳米管的比饱和磁化强度和矫顽力分别为 0 .6 6A·m2 ·kg- 1 和2 0 15 7A·m- 1 。 相似文献
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以聚乙二醇(PEG)为溶剂,高温热分解乙酰丙酮铁(Fe(acac)3)合成了磁性氧化铁纳米粒子。为改善氧化铁纳米粒子表面性能和生物应用潜能,分别用N,N二甲基甲酰胺和聚酰胺-胺(PAMAM)进行表面修饰,在氧化铁纳米粒子表面接枝-NH2活性官能团。分别采用X射线衍射仪(XRD)、透射电镜(TEM)、红外光谱(FT-IR)、动态光散射(DSL)对样品进行了表征测试。XRD和TEM结果表明高温热分解法合成的纳米粒子平均粒径为10nm,具有较好的结晶性和单分散性;FT-IR、DSL粒径和表面电位测试结果表明氨基官能团成功修饰在氧化铁纳米粒子表面,同时使氧化铁纳米粒子在水溶液中的稳定性增强。 相似文献
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纳米Ni(OH)2的控制结晶法制备 总被引:2,自引:0,他引:2
纳米Ni(OH)2可以有效地提升镍氢电池的性能. 本文以NiSO4和NaOH为原料, 聚乙二醇为分散剂, 采用控制结晶法制备了纳米Ni(OH)2的胶体溶液, 控制结晶的pH值和温度分别为11.0 和45℃. 然后用正丁醇进行共沸蒸馏处理. 制备了分散性良好的纳米Ni(OH)2粉体, 粉体颗粒粒径20nm左右, 团聚体系数为1.07. 并用TEM和XRD对粉体进行了表征. 所制备的样品在 1C倍率放电时电容量达到258mAh·g-1. 相似文献
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The heat capacity of e-H 2 with powder of FeO(OH) used as a catalyst for ortho-para equilibration has been investigated using sealed cells fabricated at the National Institute of Standards and Technology and at the National Metrology Institute of Japan. An anomalous double peak has been observed in their heat capacities at temperatures just below the triple point independent of sources of H2 and FeO(OH) and designs of sealed cells. Supercooling behavior has been observed not only at the triple point but also at each anomalous peak resulting from a depression of the melting temperature of a portion of solid H 2 in close physical proximity to the catalyst. The reduction of the amount of catalyst suppresses the size of the anomalies and allows one to obtain more reliable melting curves for e-H2 at the triple point. 相似文献
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Bundle-like structures consisting of single crystal cerium hydroxide carbonate (Ce(OH)CO3) nanorods have been synthesized successfully by a hydrothermal method at 100 °C using cerium nitrate (Ce(NO3)3·6H2O) as the cerium source, aqueous carbamide both as an alkaline and carbon source and cetyltrimethylammonium bromide (CTAB) as surfactant. X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were used to characterize such bundle-like structures. SEM and TEM images show that Ce(OH)CO3 bundle-like structures were composed of nanorods with diameters of ∼ 100 nm. The XRD pattern and electron diffraction (ED) pattern indicate that Ce(OH)CO3 has a pure orthorhombic single crystal structure. 相似文献
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The kinetics of α-FeO(OH) formation in weakacidic medium was studied.The effects of the initialconcentration,temperature,pH value,partial pres-sure of oxygen,air flow rate and agitating intensityon the oxidation rate of Fe(OH)_2 suspensions havebeen investigated.It is confirmed that the reactionorder for Fe(Ⅱ) is zero at the stage of α-FeO(OH)seeds formation,and about 0.5 at the stage of theseeds growth,and in the whole process partial pres-sure of oxygen appears in first order.The activationenergy is determined.The dissolution-oxidationequilibrium which exists in the process of seedsformation has been suggested,by which the zeroorder reaction for Fe(Ⅱ) and the plateau in thepH-t curve were explained.Physical process is therate-determining step of the heterogeneousreaction.The study on the kinetics of α-FeO(OH)formation may provide some fundamental informa-tion for the reactor design,the engineering amplifi-cation and the optimization control in the industrialprocess. 相似文献
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纳米片钠铝石结构KAl(OH)2CO3的水热合成 总被引:1,自引:0,他引:1
用水热法制备出了纳米级粒径的纤维状KAl(OH)2CO3,并研究了不同水热反应条件对KAl(OH)2CO3的形成、颗粒度以及形态的影响.研究表明,不同条件下合成的晶粒均呈纤维状,随着温度的升高,长度和粒径均有所增大.在120℃制备得到的纤维平均直径为30nm,且分布均匀;KHCO3和Al(OH)3之比对KAl(OH)2CO3的形貌有显著的影响,KHCO3用量越大,晶粒直径越细;随着介质碱性的增强,晶粒直径在pH为9.5时出现极小值,且粉体的均匀性最好.在特定的反应体系中,当反应时间达到2h后,合成反应基本达到平衡,进一步延长合成时间对粉体的形貌和颗粒尺寸没有明显的影响. 相似文献
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