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TiO2-ZrO2复合氧化物的制备与表征 总被引:3,自引:0,他引:3
采用共沉淀法制备了TiO2-ZrO2复合氧化物和单一的TiO2、ZrO2粉体,不同温度下煅烧后得到样品.用N2吸附、X-射线衍射仪、热重-差示扫描量热法对样品进行了表征.考察了单一组分与复合氧化物结构性能的差别以及煅烧温度对复合氧化物性能的影响.结果表明:550 ℃煅烧2 h后,单一TiO2、ZrO2分别是结晶良好的锐钛矿和单斜相(含少量四方相),而TiO2-ZrO2复合氧化物依然是无定型结构且具有较大的比表面积(190.15 m2/g).600 ℃煅烧后TiO2-ZrO2复合氧化物中出现了ZrTiO4晶型.随煅烧温度的升高,复合氧化物的比表面积出现了明显的下降(190.15~19.16 m2/g).DSC-TG曲线给出了TiO2、ZrO2以及TiO2-ZrO2的相转变温度,分别为440.2 ℃、445.7 ℃、713.5 ℃. 相似文献
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分别以Cu(NO_3)_2·3H_2O和50%Mn(NO_3)_2水溶液为铜源和锰源,K_2CO_3为沉淀剂,采用沉淀法和共沉淀法制备单一Cu、Mn氧化物催化剂和Cu-Mn-O复合氧化物催化剂,用于催化N_2O直接分解反应,并利用N_2物理吸附-脱附、XRD、FT-IR和TPR等进行表征。结果表明,单一Cu和Mn氧化物分别以体相CuO和Mn2O_3物相形式存在,Cu-Mn-O复合氧化物中除形成CuMn_2O_4尖晶石物相外,还有一定量小晶粒CuO,较单一氧化物具有更加优异的还原性能,表现出较高的催化N_2O直接分解活性。在空速10 000 h~(-1)和N_2O体积分数0.1%条件下,Cu-Mn-O复合氧化物催化剂可在440℃催化N_2O完全分解,分别较单一Cu和Mn氧化物催化剂降低了40℃和60℃。 相似文献
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氧化物、复合氧化物的制备 总被引:1,自引:0,他引:1
氧化物、复合氧化物作为无机功能陶瓷材料已引起世人注目。系统地介绍了固相法、气相法、共沉淀法、冷冻干燥法、溶胶-凝胶法、水溶液电解法、高压法、水热法等合成氧化物、复合氧化物的方法及其优缺点。 相似文献
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从研究应用角度出发, 综述了近年来H2O2/固体催化剂氧化脱硫体系中载体的研究进展和发展趋势, 分别从单一氧化物载体、复合氧化物载体、活性炭载体、分子筛及复合分子筛载体4个方面论述了氧化脱硫催化剂载体各自的优缺点及应用成果。单一氧化物载体重点介绍了Al2O3、TiO2、SiO2、ZrO2;复合氧化物载体主要对二元复合氧化物进行了综述;重点介绍了以ZSM-5、SBA-15、MCM-41、HMS为代表的分子筛及复合分子筛载体。最后将不同类型载体的结构特点、反应优缺点等进行了归纳总结, 展望了氧化脱硫催化剂载体未来的研究方向, 并提出分子筛及复合分子筛载体将是氧化脱硫催化剂载体研究的焦点。 相似文献
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分别采用溶胶-凝胶法和共沉淀法制备了TiO2-SiO2复合氧化物,并以此复合氧化物为载体制备了加氢脱硫催化剂.采用氮气恒温吸附脱附、X射线衍射、傅立叶变换红外光谱(FT-IR)和NH3程序升温脱附实验(NH3-TPD)对TiO2-SiO2复合氧化物及其催化剂进行表征,并考察催化剂的加氢脱硫性能.结果表明,TiO2经SiO2复合改性后,其热稳定性和晶相稳定性得到了提高.溶胶-凝胶法与共沉淀法相比,能使Ti物种和Si物种混合得更均匀,从而有利于制得具有较大比表面积和孔容的TiO2-SiO2复合氧化物.Ti含量增加,复合氧化物中Ti的分散度会降低.TiO2-SiO2复合氧化物中以Lewis酸中心为主,共沉淀法制备的复合氧化物比溶胶-凝胶法制备的复合氧化物具有更多的酸性中心.具有较大比表面积和较高酸性的催化剂对模型化合物噻吩和锦西重油催化裂化柴油的加氢脱硫性能较高. 相似文献
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采用共沉淀法和高温煅烧制备了AlMn复合氧化物、FeMn复合氧化物、ZnMn复合氧化物和BiSn复合氧化物,采用X射线衍射仪和扫描电子显微镜对产物的物相结构、形貌等进行了表征;并将4种复合氧化物作为铝–空气电池空气电极催化剂进行了恒流放电、循环伏安、交流阻抗、阴极极化测试。结果表明:所制备的4种复合氧化物形貌皆不同。除AlMn复合氧化物外,其他3种复合氧化物都具有较好的催化性能。FeMn复合氧化物组成的电极活性最差。用ZnMn复合氧化物制备的电池在20mA/cm~2的电流密度下电压平台高达1.46V,在100mA/cm~2电流密度下还能保持0.72V,相比其他3种复合氧化物其性能最佳。 相似文献
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Laura Soupas Laura Juntunen Suvi Säynäjoki Anna-Maija Lampi Vieno Piironen 《Journal of the American Oil Chemists' Society》2004,81(2):135-141
A new GC-MS method for characterization and quantification of phytosterol oxidation products was developed. Applicability
of this method was tested by characterizing sitostanol oxides formed in bulk and then quantifying selected oxides in purified
rapeseed oil and tripalmitin matrices in which the complex matrix made oxide analysis difficult. In bulk, nine different sitostanol
oxides were characterized, including epimers of 7- and 15-hydroxysitostanol and 6- and 7-ketositostanol. In both lipid matrices,
the amounts of sitostanol oxides generated in thermo-oxidation were very low. According to statistical analyses, depending
on the oxide, the GC-MS results were the same or slightly higher than those quantified by the more common GC-FID method. Thus,
GC-MS provides a powerful alternative for characterization and quantification of phytostanol oxides found in low amounts in
complex matrices and is a promising method for future phytosterol oxide studies. 相似文献
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偏最小二乘法—人工神经网络用于复氧化物形成条件的判别 总被引:2,自引:1,他引:2
本文应用人工神经网络算法结合偏最小二乘算法,对两元氧化物系化学键参数进行模式识别分析,用计算机对两不同的氧化物间是否有复合氧化物生成进行分类和预报,得到满意的结果。为了确定两氧化物间是否有复氧化物生成,本文首先用PLS回归算法初选化学键参数,通过样本点在PLS正交分解矢量平面上的投影图,按形成与不形成对两元氧化物进行分类,从而确定一组对复氧化物形成影响最大的化学键参数,实现对能否生成复氧化物进... 相似文献
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CuNiAl复合金属氧化物催化ClO2氧化处理苯酚废水 总被引:1,自引:1,他引:0
采用共沉淀法合成CuNiAl类水滑石(CuNiAl-LDHs),将水滑石在600℃下焙烧制备出高分散CuNiAl复合金属氧化物催化剂,用XRD、FTIR和SEM对产品进行表征,并用CuNiAl复合金属氧化物催化ClO2氧化处理苯酚。研究结果表明,类水滑石中Cu、Ni、Al的摩尔比影响类水滑石的晶形结构,当n(Cu)∶n(Ni)∶n(Al)=1∶1∶1,可以得到结晶度高、晶体单一的CuNiAl类水滑石,该水滑石焙烧得到的复合金属氧化物催化ClO2氧化处理苯酚废水,可促进废水中苯酚的深度降解,使COD去除率大大提高。适宜的反应条件是:催化剂投加量为3 g/L,废水pH=7.0,反应时间60 min,反应温度室温,废水COD去除率达到65%左右。 相似文献
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《Journal of the European Ceramic Society》2000,20(5):639-644
Strategies which have been used in the synthesis of high temperature interphases with debond capability in oxide/oxide systems have been: (i) the formation of layered oxides (β-aluminas or magnetoplumbites) with preferred crystal orientation due to in-situ interface reactions between phases deposited from vapour or liquid precursors and (ii) the deposition on fibre surfaces of complex oxides (vanadates and phosphates, principally of the rare earths) from colloidal precursors or by magnetron sputtering. This paper is primarily concerned with the latter. The constitution and thermal stability of these interphases has been studied with reference to potential fibres and matrices (alumina, YAG and mullite). Included within the program are newly developed single phase mullite fibres and examples of these are also presented. 相似文献
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由于氮氧化物特殊的物理化学性质,对燃烧过程中生成的NOx实施控制是一项复杂的技术。本文介绍了NOx的形成机理,阐述了氮氧化物排放控制技术的发展与科研进展,并重点介绍了SCR、等离子体过程烟气脱硝技术。 相似文献
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Fine and homogeneous powders of Y-Ba-Cu complex oxides are necessary to improve the quality of YBCO bulk high temperature superconductors. The powders which contain BaCO3 must be sintered for producing YBCO super-conductors at temperature above 850 °C. Therefore, complex oxide is desired. In order to prepare fine complex oxides powders, suspension was synthesized by simultaneous hydrolization of 2-propanol solution of metal isopropoxides. However, the suspension was not dried by a hot air drying method, because aggregation occurs due to cohesion of particle along with evaporation. Also, the suspension could not be freeze-dried, because the freezing point of 2-propanol is -88.5°C. So, supercritical fluid drying method using supercritical carbon dioxide was applied. The results from these experiments suggest that this method is useful for drying of the suspension prepared by the alkoxide route. 相似文献
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Hiroyuki Hayashi Yuta Morimitsu Ikko Tatsumi Isao Tanaka 《International Journal of Applied Ceramic Technology》2023,20(1):125-130
Coordination polymers (CPs) are assembled from metal ions and organic linker molecules. Here, we demonstrate that CPs can be used as precursors for simple and complex oxide synthesis. First, we investigated the conditions for linker solutions in which CP was obtained as precipitate only by mixing and stirring the solutions for each of the 28 metal–ion aqueous solutions. Evaluation of the crystalline phase of the samples obtained by firing the precipitates revealed that CPs could be used as precursors of simple oxides for 21 metal ions. Next, we conducted experiments to prepare precursors of 10 complex oxides with an AnBnOm composition containing equimolar amounts of metal ions. Seven complex oxides were successfully synthesized. Three of them were complex oxides that could not be synthesized by the spray coprecipitation method. The present method has a comparable precursor preparation capability to the spray coprecipitation method. Because of the much shorter time for the precursor synthesis, the present method should be useful for parallel and automated experiments. 相似文献