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1.
自生纳米纤维增强SiO_2气凝胶的制备及性能研究 总被引:2,自引:0,他引:2
采用溶胶-凝胶法和乙醇超临界干燥工艺制备ZrOX/SiO2复合气凝胶,再经1 200℃高温热处理得到自生纳米纤维增强SiO2复合气凝胶。利用扫描电子显微镜、透射电子显微镜、X射线衍射、热重和氮气吸附等手段对气凝胶的结构和性能进行了分析,并且测试了样品的压缩强度及真密度。实验结果表明:自生纳米纤维增强SiO2复合气凝胶具有均匀的多孔网络结构,锆氧纳米纤维是以化学键连接复合的方式无序穿插在气凝胶中,对复合气凝胶的机械强度和隔热性能有明显的改善。经1 200℃热处理后的ZrOX/SiO2复合气凝胶比表面积为827.22 m2·g-1,压缩强度为9.68 MPa,真密度为0.23 g·cm-3。 相似文献
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镍含量对NiO/SiO2气凝胶性能的影响 总被引:3,自引:0,他引:3
A series of NiO/SiO2 aerogel catalysts were prepared by sol-gel method. The effects of the nickel content on the structure and existing forms of NiO/SiO2 aerogel catalysts were investigated by using XRD, TPR and FT-IR. The results showed that there were interactions between NiO and SiO2. But as nickel content increased, the in-teraction decreased. The nickel oxide in the catalysts appeared in different forms as nickel content was changed. When the content was less than 13%, Ni(Ⅱ) entered into the SiO2 structure completely and it became clusters after calcining. If the content altered from 20% to 50%, NiO existed as both microcrystal and clusters, the later spices was dominating. However, when the content increased to 70%, microcrystal became the primary components. 相似文献
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A new type of nanoporous SiO2 aerogel microsphere materials were synthesized by using SiO2 sols as raw materials in the W/O emulsion formed by the emulsification of Tween-85 and Span-80. The obtained wet gel microspheres were aged by a successive solvent exchanging of alcohol, tetraethylorthosilicate (TEOS)/ethanol solution and ethanol at 60 ℃, and then were dried at ambient pressure to produce SiO2 aerogel microspheres. The resultant SiO2 aerogel microspheres were characterized by SEM, TEM and nitrogen adsorption-desorption. The results show that the prepared SiO2 aerogel microspheres are nanoporous materials with coherent network nanoporous structure consisting of SiO2 nanoparticles with an average diameter of about 10 nm. The apparent density of a typical sample is 0.4 g·cm-3, while the specific surface area is 386 m2·g-1, and the average pore size is 18 nm with the porosity of 84%. Various SiO2 aerogel microspheres with the apparent particle sizes of 10~200 μm can be synthesized by controlling the stirring speed at 600~2 000 r·min-1, the volume ratio of water/oil from 0.10 to 0.30, and the weight ratio of Tween-85/Span-80 less than 0.40. 相似文献
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块状TiO2/SiO2气凝胶的非超临界干燥法制备及其表征 总被引:11,自引:0,他引:11
分别通过TiO2和SiO2的单独溶胶和TiO2/SiO2复合凝胶,并添加干燥控制化学添加剂甲酰胺,形成比较完善的凝胶网络结构,同时通过正硅酸乙酯的乙醇溶液浸泡,低表面张力溶剂替换和分级陈化以及干燥等步骤,实现了块状TiO2/SiO2复合气凝胶的非超临界干燥制备.所得TiO2/SiO2气凝胶为无色或乳白色轻质块状多孔固体,表观密度约0.4~0.9g/cm3,孔隙率约80%~95%.它由直径约10nm的TiO2和SiO2微粒相互分散复合而成,孔洞直径约几十纳米.其相态SiO2为无定形,TiO2为锐钛矿晶型.随着焙烧温度的升高,直到800℃不发生相变化. 相似文献
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介孔SiO2气凝胶的常压干燥制备研究 总被引:4,自引:0,他引:4
以廉价的水玻璃为硅源,用乙醇(EtOH) / 三甲基氯硅烷(TMCS) / 庚烷(Heptane)溶液对湿凝胶进行改性,采用一种新的常压干燥工艺合成了SiO2气凝胶。通过TMCS与乙醇、湿凝胶孔隙水及Si-OH基团之间的反应,使湿凝胶的溶剂交换和表面改性得以在一步完成。所合成的SiO2气凝胶为轻质透明的块状固体,密度为0.128~0.136 g·cm-3,孔隙率93.8%~94.2%。利用FTIR、SEM、TEM和BET吸附对气凝胶的微观结构、形貌和性质进行了研究。结果表明,气凝胶为海绵状结构,粒子直径和孔径分布均匀,比表面积559~618 m2·g-1,表面带有较多的Si-CH3基团,呈现出明显的疏水性。 相似文献
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SiO2/ZnO复合纳米粒子的制备及表征 总被引:10,自引:1,他引:10
采用双注控制沉积法(Controlled Double-Jet Precipitation,CDJP)将反应物添加到含有SiO2的溶液中,通过直接的表面反应来制备单分散的SiO2/ZnO复合纳米粒子,并对其进行了表征。透射电镜(TEM)观察表明,SiO2表面有一层ZnO纳米颗粒或薄层。对复合纳米粒子SiO2/ZnO进行X射线衍射(XRD)分析,复合颗粒的衍射峰与单独的氧化锌的衍射峰完全一致。能量弥散X射线法(EDX)分析表明,复合颗粒中含有Zn、Si、O元素。荧光光谱表明有ZnO的吸收峰。 相似文献
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以正硅酸四乙酯(TEOS)为前驱体,YCl3·6H2O为掺杂剂,采用溶胶-凝胶法并结合CO2超临界干燥工艺得到了块状Y2O3-SiO2气凝胶,其中Y2O3掺杂含量控制在5wt%~30wt%范围内。利用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、比表面积测定(BET)、X射线荧光分析(XRF)等测试手段对样品进行表征。结果表明:经过氧化钇掺杂后得到的Y2O3-SiO2气凝胶,不仅维持了SiO2气凝胶原有的空间网络结构,而且具有更高的热稳定性,经过900℃热处理2h后,10wt%Y2O3(0.447g的YCl3·6H2O)掺杂的Y2O3-SiO2气凝胶仍然处于无定形态,平均孔径约为21.3nm,比表面积高达643.8m2·g-1。 相似文献
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PVA/SiO2-TiO2杂化电纺纤维膜的形态与性能 总被引:1,自引:0,他引:1
以正硅酸乙酯(TEOS)、钛酸四丁酯(TBT)和聚乙烯醇(PVA)为原料, 用溶胶凝胶法制备了PVA/(SiO2-TiO2)杂化纺丝液, 将其电纺成纤维膜. 红外光谱结果证实, PVA的羟基与TEOS和TBT水解后的羟基发生了缩合反应, 杂化电纺纤维膜以网络结构形式相结合; X射线衍射分析表明, 杂化电纺纤维膜的结晶度比纯PVA电纺纤维膜小; 扫描电镜表明, 随杂化纤维膜中无机相含量的增加, 纤维的直径不断增加, 纤维出现一定的弯曲和扭曲, 并伴有少量带状结构的纤维; 紫外-可见光谱结果表明, TiO2的引入增加了纤维膜的抗紫外性; TGA热分析结果表明, 杂化纤维膜的耐热性能优于纯PVA电纺纤维膜的; 耐水性和稳定性测试表明, 杂化纤维膜的耐水性和稳定性优于纯PVA和PVA/SiO2电纺纤维膜的. 相似文献
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微乳法制备纳米TiO2 /SiO2的结构及光催化研究 总被引:1,自引:0,他引:1
Nanosized TiO2 and TiO2/SiO2 particles were prepared by hydrolysis of tetrabutyl titanate (TBOT) and tetraethyl orthosilicate (TEOS) in the TX-100 reverse microemulsion. These particles were characterized by TG-DSC, XRD, FTIR, TEM,N2 adsorption-desorption. Their photocatalytic activity was tested by degradation of methyl orange. The result shows that TiO2/SiO2 nanoparticles are with a monodispersed spherical phase and a uniform size distribution,and TiO2 particles are dispersed on the surface of SiO2. The band for Ti-O-Si vibration in FTIR was observed, the Ti-O-Si bond increased the stability of anatase TiO2, suppressed the phase transformation of titania from anatase to rutile. And due to the addition of SiO2, the average size of titania decreased from 38 nm in pure TiO2 to 5 nm in TiO2/SiO2. It was found, under UV light irradiation, TiO2/SiO2 particles showed higher activity than pure TiO2, and TiO2/SiO2(1/1) particles showed the highest photocatalytic activity on the photocatalytic decomposition of methyl orange, which was influenced by crystal structure, particle size, crystallinity and Surface area Characteristics. 相似文献
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轻质高强度C/Al2O3复合气凝胶的制备及表征 总被引:1,自引:0,他引:1
采用溶胶-凝胶法和CO2超临界干燥工艺制备RF/Al2O3复合气凝胶,再经高温热处理过程得到轻质高强度C/Al2O3复合气凝胶,研究了不同热处理温度对气凝胶结构的影响,利用氮气吸附、X射线衍射、扫描电子显微镜和透射电子显微镜等手段对气凝胶的结构和性能进行了分析并且测试了不同热处理温度样品的压缩强度。实验结果表明:C/Al2O3复合气凝胶具有均匀的三维网络结构且成块性好,随着热处理温度的升高,气凝胶比表面积和强度均先增大后减小,当1 400℃时,C/Al2O3复合气凝胶比表面积最高,为831 m2.g-1,压缩强度最大,为9.5 MPa。 相似文献
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氧化钇掺杂块状SiO_2气凝胶的制备与表征 总被引:2,自引:0,他引:2
以正硅酸四乙酯(TEOS)为前驱体,YCl3·6H2O为掺杂剂,采用溶胶-凝胶法并结合CO2超临界干燥工艺得到了块状Y2O3-SiO2气凝胶,其中Y2O3掺杂含量控制在5wt%~30wt%范围内。利用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、比表面积测定(BET)、X射线荧光分析(XRF)等测试手段对样品进行表征。结果表明:经过氧化钇掺杂后得到的Y2O3-SiO2气凝胶,不仅维持了SiO2气凝胶原有的空间网络结构,而且具有更高的热稳定性,经过900℃热处理2 h后,10wt%Y2O3(0.447 g的YCl3·6H2O)掺杂的Y2O3-SiO2气凝胶仍然处于无定形态,平均孔径约为21.3 nm,比表面积高达643.8 m2·g-1。 相似文献
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TiO2/SiO2纳米薄膜的光催化活性和亲水性 总被引:17,自引:0,他引:17
通过sol gel工艺在钠钙玻璃表面制备了均匀透明的TiO2/SiO2复合纳米薄膜.实验结 果表明: 当SiO2添加量较高时, TiO2/SiO2复合纳米薄膜的光催化活性明显降低;当SiO2添加 量较低时,TiO2/SiO2复合薄膜的光催化活性无明显变化.在TiO2薄膜中添加SiO2,可以抑制薄 膜中TiO2晶粒的长大,同时薄膜表面的羟基含量增加, 水在复合薄膜表面的润湿角下降, 亲 水能力增强.当SiO2含量为10%-20%(摩尔分数)时获得了润湿角为0°的超亲水性薄膜. 相似文献
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本文通过溶胶-凝胶法,以正硅酸乙酯、聚乙二醇和明胶为主要原料,制得了孔径约为20 nm的生物酶载体用多孔SiO2块状材料,并着重研究了热处理温度对多孔SiO2载体的结构和酶活力的影响。明胶的加入能有效地防止SiO2表面羟基在烧结过程中的失活现象,提高了多孔材料的吸附能力。制备过程中未加入明胶样品(G0)的酶吸附量和初始酶活力回收率的最高值分别为90 mg·g-1和11%;加入质量分数为15%明胶的样品(G15)的酶吸附量和初始酶活力回收率分别提高到115 mg·g-1和38%以上。经过5次重复使用后,G15载酶块体所显示的酶活力还高于G0载酶块体的初始酶活力。600 ℃热处理后所制得的G15样品表现出较好的综合性能,此类多孔块体材料便于酶的回收、保存和再利用。 相似文献
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The gradient composite LiNi0.8Co0.2O2 was synthesized using spherical Ni(OH)2 particle coated by a sol-gel containing cobalt and lithium. The precursor was examined by DSC-TG. The gradient composite was characterized by SEM, EDS, XPS, XRD and ICP-AES. The XPS, EDS and ICP-AES results show that content of cobalt in the surface is higher than in the center of the spherical particle of the gradient composite. The first discharge specific capacity of the gradient composite sintered at 700 ℃ is 187.3 mAh·g-1. 相似文献
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V.M. Bogatyrev V.M. Gunko M.V. Galaburda M.V. Borysenko V.A. Pokrovskiy O.I. Oranska E.V. Polshin O.M. Korduban R. Leboda J. Skubiszewska-Ziba 《Journal of colloid and interface science》2009,338(2):376-388
Fe2O3/SiO2 nanocomposites based on fumed silica A-300 (SBET = 337 m2/g) with iron oxide deposits at different content were synthesized using Fe(III) acetylacetonate (Fe(acac)3) dissolved in isopropyl alcohol or carbon tetrachloride for impregnation of the nanosilica powder at different amounts of Fe(acac)3 then oxidized in air at 400–900 °C. Samples with Fe(acac)3 adsorbed onto nanosilica and samples with Fe2O3/SiO2 including 6–17 wt% of Fe2O3 were investigated using XRD, XPS, TG/DTA, TPD MS, FTIR, AFM, nitrogen adsorption, Mössbauer spectroscopy, and quantum chemistry methods. The structural characteristics and phase composition of Fe2O3 deposits depend on reaction conditions, solvent type, content of grafted iron oxide, and post-reaction treatments. The iron oxide deposits on A-300 (impregnated by the Fe(acac)3 solution in isopropanol) treated at 500–600 °C include several phases characterized by different nanoparticle size distributions; however, in the case of impregnation of A-300 by the Fe(acac)3 solution in carbon tetrachloride only α-Fe2O3 phase is formed in addition to amorphous Fe2O3. The Fe2O3/SiO2 materials remain loose (similar to the A-300 matrix) at the bulk density of 0.12–0.15 g/cm3 and SBET = 265–310 m2/g. 相似文献