以表面活性剂为模板ZrO2薄膜在空气-水界面的自组装研究

采用三种阴离子表面活性剂: 十二烷基磺酸钠(SDS), 十二烷基苯磺酸钠(DBS-Na), 十二烷基苯磺酸(DBS-H)作模板, 在空气-水界面上组装ZrO₂薄膜. 结果表明, 采用SDS组装的薄膜具有良好的机械强度. 经X射线能量扫描谱原位检测以及X射线衍射(XRD)谱检测证实, 所获薄膜为层状结构, 其层间距在2.70～3.54 nm之间. 利用所建立的层状结构模型解释了各种阴离子表面活性剂组装ZrO₂薄膜并控制层间距变化的机理.     

以表面活性剂为模板ZrO2薄膜在空气-水界面的自组装研究

采用三种阴离子表面活性剂: 十二烷基磺酸钠(SDS), 十二烷基苯磺酸钠(DBS-Na), 十二烷基苯磺酸(DBS-H)作模板, 在空气-水界面上组装ZrO₂薄膜. 结果表明, 采用SDS组装的薄膜具有良好的机械强度. 经X射线能量扫描谱原位检测以及X射线衍射(XRD)谱检测证实, 所获薄膜为层状结构, 其层间距在2.70～3.54 nm之间. 利用所建立的层状结构模型解释了各种阴离子表面活性剂组装ZrO₂薄膜并控制层间距变化的机理.     

Au/ZrO2催化剂中ZrO2的尺寸效应:1,3-丁二烯加氢反应

在不同温度(673～1073K)下,于流动N2气中焙烧ZrO(OH)2醇(乙醇)凝胶,制备了不同尺寸的ZrO2-AN纳米晶(6～30nm).采用沉积-沉淀方法制备了相应的质量分数为0.7%的Au/ZrO2-AN催化剂.用XRD,XRF,TEM/HRTEM,EDS,N2吸附和1,3-丁二烯加氢反应对ZrO2-AN和Au/ZrO2-AN催化剂进行了表征.结果表明,在所有的Au/ZrO2-AN样品中,Au粒子的平均尺寸为4～5nm,ZrO2-AN的颗粒大小没有因为负载Au粒子而发生改变.1,3-丁二烯在Au/ZrO2-AN催化剂催化下能以100%的选择性进行加氢反应生成单烯烃.随着Au/ZrO2-AN催化剂中ZrO2-AN纳米晶尺寸的增加或“载体”焙烧温度的升高,1,3-丁二烯的转化率明显降低;1-丁烯的选择性先增加后减小,2-丁烯中反/顺异构体的摩尔比在0.5～1.0的范围内逐渐增大,TEM/HRTEM表征结果清楚地表明,Au/ZrO2-AN催化剂中Au粒子与ZrO2-AN颗粒接触界面/周边随ZrO2-AN颗粒尺寸的减小而明显增加,这很可能是含有更小尺寸ZrO2-AN纳米粒子的Au/ZrO2-AN催化剂具有更高的催化活性的重要原因.     

ZrO4/SiO2-Al2O3催化肉桂醛MPV转移加氢性能

以九水合硝酸铝（Al（NO₃）₃·9H₂O）与正硅酸乙酯（TEOS）为前驱盐,采用溶胶-凝胶法制备一系列不同Al₂O₃含量的SiO₂-Al₂O₃复合氧化物,并通过浸渍硝酸氧锆引入ZrO₂,制备ZrO₂/SiO₂-Al₂O₃复合氧化物催化剂,考察催化剂在肉桂醛（CAL）MPV转移加氢中的催化性能,并结合N₂物理吸附、X射线粉末衍射（XRD）、傅里叶变换红外光谱（FTIR）、NH₃-程度升温脱附（NH₃-TPD）、Py-原位红外（Py-IR）等技术,研究催化剂结构、织构以及表面性质与其催化性能间的构效关系.研究表明,所制备的催化剂均以L酸为主,并含有少量B酸中心,这使得加氢产物以肉桂醇（COL）为主,并含有少量1-苯丙烯-2-丙基醚（CPE）.Al₂O₃含量不仅影响催化剂表面的酸中心数量,而且对催化剂的织构参数有较大影响.随Al₂O₃含量的增加,催化剂表面L酸与B酸中心均有所增加,而孔径则持续变小,这使得催化反应呈现CAL转化率先增加后减少、目标产物COL选择性先稍有减小后有所增加的趋势.在Si/Al比为2时,催化剂具有最优的催化性能,优化反应条件下,CAL转化率达96%,目标产物COL选择性达90%.     

Cu/ZrO2催化剂中的氢和水逆溢流效应及其对甲醇分解反应的影响

应用漫反射红外和质谱在线技术对H₂, H₂O及甲醇在ZrO₂及Cu/ZrO₂上的程序升温脱附(TPD)及程序升温反应(TPSR)行为进行了研究. 结果表明, Cu/ZrO₂催化剂中铜锆组分间表现出显著的氢和水组分“逆溢流”效应. 对Cu/ZrO₂催化体系中ZrO₂表面线式及桥式羟基物种浓度随还原预处理温度变化的进一步分析表明, 由于氢和水“逆溢流效应”的存在, 使得Cu/ZrO₂在较低的还原温度下活化的同时, 在铜锆界面处形成较丰富的氧阴离子和氧空穴活性位, 而后者的形成与存在直接影响并决定了甲醇在Cu/ZrO₂催化剂上的低温催化分解行为.     

Cu/ZrO2催化剂中的氢和水逆溢流效应及其对甲醇分解反应的影响

应用漫反射红外和质谱在线技术对H₂, H₂O及甲醇在ZrO₂及Cu/ZrO₂上的程序升温脱附(TPD)及程序升温反应(TPSR)行为进行了研究. 结果表明, Cu/ZrO₂催化剂中铜锆组分间表现出显著的氢和水组分“逆溢流”效应. 对Cu/ZrO₂催化体系中ZrO₂表面线式及桥式羟基物种浓度随还原预处理温度变化的进一步分析表明, 由于氢和水“逆溢流效应”的存在, 使得Cu/ZrO₂在较低的还原温度下活化的同时, 在铜锆界面处形成较丰富的氧阴离子和氧空穴活性位, 而后者的形成与存在直接影响并决定了甲醇在Cu/ZrO₂催化剂上的低温催化分解行为.     

TiO2薄膜空气-水界面自组装的研究

本文采用十二烷基磺酸钠(SDS)作模板并以明胶作稳定剂，在空气-水的界面上组装TiO₂薄膜。结果表明，采用明胶稳定的薄膜具有良好的机械强度。采用X射线角度扫描技术(AD)原位检测薄膜的结构，并用X射线宽角衍射(WAXS)和小角衍射(SAXS)技术对经后续处理的TiO₂薄膜结构进行了表征。研究发现，明胶的加入可显著降低薄膜中TiO₂颗粒细度；经洗涤后，此复合薄膜材料可转换成纯层状的TiO₂薄膜。分析了明胶稳定TiO相似文献   

有机体系中纳米TiO2 / ZrO2修饰电极的制备及电催化活性

The complexes Ti(OCH₂CH₂O)₂ and Zr(OCH₂CH₂O)₂ were directly synthesized by using HOCH₂CH₂OH dissolution in 50 mL flask. The nano-ZrO₂ / TiO₂ powders were prepared by a direct sol-gel synthesis using the above solution and followed by drying at 400 ℃ for 2 h. The complexes were characterized by FTIR and ¹H NMR. XRD and TEM were used to investigate the structure of nano-ZrO₂ / TiO₂. The results show that the complexes containing ^-OCH₂CH₂O^- group could prevent the precursor from agglomeration and sintering during the hydrolysis and calcination process. The ZrO₂ / TiO₂ powders of 20～35 nm was thus obtained in a high purity. The highly active nano-ZrO₂ / TiO₂ modified electrode was prepared by using daubing and calcination. The electro-catalytic activities of this electrode in (COOH)₂ were investigated. The discharge current of nano-ZrO₂ / TiO₂ electrode increased obviously. In preparative electrolysis under optimal conditions, the average yield and current efficiency for HOOC-CHO were 84.7% and 91.6 %, respectively.     

Li2ZrO3材料吸收CO2性能的进一步研究

用不同结构的ZrO₂合成了一系列在高温下吸收CO₂的Li₂ZrO₃材料，并详细的研究了反应物质的物理和化学性质对生成物吸收CO₂性能的影响。采用SEM、XRD以及TG分析法分别进行了材料结构及其吸收CO₂性能的表征，并使用XPS法测定了材料表面的元素组成。实验结果表明，使用不同结构的ZrO₂合成的Li₂ZrO₃，其吸收CO₂的性能明显的不同。用ZrO₂(t)(四方)合成的Li₂ZrO₃吸收CO₂的速度快，在500 ℃下，20% CO₂（80%空气）的气氛中保持3h，其吸收量可达25（±0.6）%（wt），而以ZrO₂(m)(单斜)为原料制备的Li₂ZrO₃在上述吸收条件下重量仅增加9（±0.6）%（wt）。此外，实验结果还表明化学元素的掺杂对用ZrO₂(m)合成的Li₂ZrO₃的CO₂吸收速度及吸收容量影响较大。     

(ZrO2)0.92(Gd2O3)0.08纳米晶的水热合成及其烧结体的电性能

用新制备的(Gd，Zr)(OH)_x·yH₂O共沉淀作前驱体，在强碱性介质中用水热法合成了(ZrO₂)_0.92(Gd₂O₃)_0.08纳米立方晶，考察了反应温度、pH值等水热反应条件对纳米晶粒大小的影响。将(ZrO₂)_0.92(Gd₂O₃)_0.08     

大孔SO42-/ZrO2-SiO2复合固体酸制备及催化性能

利用浸渍水解法在大孔SiO2载体上组装固体酸制备出大孔径SO42-/ZrO2-SiO2复合固体酸催化剂。用扫描电镜、红外光谱仪和粉末X射线衍射仪等对其进行表征,结果表明:大孔SiO2载体的毛细管效应促使ZrO2以纳米薄层方式均匀地沉积在SiO2薄层表面,并抑制了ZrO2晶体的生长和晶相的转变,载体的大孔全连通的结构赋予该复合材料高的通透性(孔径在1~2μm)、两面活性点和大的比表面积(约156 m2.g-1)。Hammett指示剂法测得经550℃焙烧后产物的酸强度H0值小于-13.75,属于固体超强酸。以乙酸正丁酯的合成为探针反应考察硫酸浸渍液浓度、焙烧温度等制备条件对其催化活性的影响,结果表明,该SO42-/ZrO2-SiO2固体酸具有较好的催化活性,当焙烧温度为550℃和硫酸浸渍液浓度为1.5 mol.L-1时,超强酸对酯化反应的催化酯化率达到97%。     

Preparation of ZrO2-TiO2-CeO2 and Its Application in the Selective Catalytic Reduction of NO with NH3

TiO₂,ZrO₂-TiO₂,andZrO₂-TiO₂-CeO₂ were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), specific surface area measurements (BET), temperature programmed desorption (NH₃-TPD), oxygen storage capacity (OSC), and temperature programmed reduction (H₂-TPR). The results showed that ZrO₂-TiO₂-CeO₂ exhibited large number of surface strong acid, possessed some oxygen storage capacity, and strong redox property. The three materials were used as supports and the monolith catalysts were prepared with 1% (w) V₂O₅ and 9% (w)WO₃ for selective catalytic reduction (SCR) of NO with ammonia in the presence of excessive O₂, and the results of catalytic activity showed that the catalyst used ZrO₂-TiO₂-CeO₂ as support yielded nearly 100% NO conversion at 275 °C at a gas hourly space velocity (GHSV) of 10000 h⁻¹, and it had the best catalytic activity and showed great potential for practical application.     

三维有序大孔Ag/ZrO2-TiO2：制备及紫外光催化降解染料和水杨酸性能

采用聚苯乙烯(PS)微球作为模板剂,经溶胶-凝胶及煅烧后处理的方法制备了三维有序大孔(3DOM)复合材料Ag/ZrO2-TiO2。通过FTIR、XRD、XPS、N2吸附-脱附和SEM-EDS等对其进行了表征。结果显示,经PS微球作用后的复合材料Ag/ZrO2-TiO2具有锐钛矿晶型结构,其Ag以单质形式存在。该复合材料的孔结构高度有序,属三维有序大孔,平均孔直径为120 nm,孔壁由紧密堆积的Ag/ZrO2-TiO2纳米晶粒组成,孔收缩率约为40%。该复合材料表现出较好的紫外光催化降解水杨酸和甲基橙等染料性能,其活性明显高于商用光催化剂(Degussa P-25)、Ag/ZrO2-TiO2和3DOM ZrO2-TiO2,在90 min内对甲基橙的降解率达80.1%。     

Structural characterization and photocatalytic activity of hollow binary ZrO2/TiO2 oxide fibers

The formation of hollow binary ZrO₂/TiO₂ oxide fibers using mixed precursor solutions was achieved by activated carbon fibers templating technique combined with solvothermal process. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N₂ adsorption, X-ray photoelectron spectroscopy (XPS), UV-vis, and infrared (IR) spectroscopy. The binary oxide system shows the anatase-type TiO₂ and tetragonal phase of ZrO₂, and the introduction of ZrO₂ notably inhibits the growth of TiO₂ nanocrystallites. Although calcined at 575 °C, all hollow ZrO₂/TiO₂ fibers exhibit higher surface areas (>113 m²/g) than pure TiO₂ hollow fibers. The Pyridine adsorption on ZrO₂/TiO₂ sample indicates the presence of stronger surface acid sites. Such properties bring about that the binary oxide system possesses higher efficiency and durable activity stability for photodegradation of gaseous ethylene and trichloromethane than P25 TiO₂. In addition, the macroscopic felt form for the resulting materials is more beneficial for practical applications than traditional catalysts forms.     

制备方法对CuO-CeO2/ZrO2催化CO氧化性能的影响

以ZrO2为载体、采用不同的浸渍次序制备了3种CuO-CeO2/ZrO2催化剂并在不同的温度(500,650和800℃)下进行焙烧,利用X射线衍射(XRD)、程序升温还原(H2-TPR和CO-TPR)及CO程序升温脱附(CO-TPD)技术对所制备的催化剂进行了表征,并采用色谱流动法考察了其催化CO低温氧化反应性能。结果表明,当焙烧温度为650℃时,3种催化剂的CO催化氧化活性均最佳,且三者的催化活性大小顺序为:CuO/CeO2/ZrO2>CuO-CeO2/ZrO2>CeO2/CuO/ZrO2。结合催化剂的表征和活性测试结果,我们认为高分散的CuO是CO的吸附中心,有利于CO的低温氧化反应,而大颗粒的CuO几乎对CO没有吸附作用,不利于CO的低温氧化反应。在3种催化剂中,CuO/CeO2/ZrO2催化剂具有最佳的低温还原特性和最大的CO2脱附峰面积,相应地具有最佳的催化氧化活性。     

制备方法对WO3/ZrO2结构的影响

WO3/ZrO2 catalysts prepared from Zr(OH)4 and crystallized ZrO2 have been characterized by means of XRD, LRS (qualitative and quantitative), and the specific sufrace area has been measured. The influence of the preparation method, the contents of WO3 in the samples and the calcination tempearture on the specific surface areas of the samples, the phase of support and the structural states of active component has been studied. The results show: (1) WO3 can disperse on ZrO2 as a monolayer; (2) WO3 dispersed on Zr(OH)4 as a monolayer retards the crystalline growth of the support on calcination, makes it crystallizing into a metastable tetragonal modification, and prevents the inter- crystalline sintering between the crystallites of ZrO2. These factors would result in an increase in the specific surface area of WO3／ZrO2 prepared from Zr(OH)4. As the content of WO3 in the sample comes up to its monolayer capacity, this effect is displayed most fully. A chemical reaction can occur between WO3 and Zr(OH)4 (or the tetragonal ZrO2) at a high temperature(800℃),producing some superacid sites on the surface. By these views, the main experimental facts published in the literatures can been interpreted satisfactotily.     

Acidic properties of V2O5-WO3/ZrO2 catalysts

The adsorption of pyridine on V₂O₅−WO₃/ZrO₂ has been studied by FTIR. In V₂O₅/ZrO₂ (2 wt.%), the number of both Br?nsted and Lewis acidic sites increased with the addition of WO₃, while in V₂O₅/ZrO₂ (5 wt.%), Br?nsted sites increased and Lewis sites did not change.     

Monolith Manganese-Based Catalyst Supported on ZrO2-TiO2 for NH3-SCR Reaction at Low Temperature

Monolith catalysts were prepared using TiO₂ and ZrO₂-TiO₂ as supports with MnO₂ as active component and Fe₂O₃ as promoter. The catalytic activities at low temperature and stability at high temperature for selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) in the presence of excessive O₂ were studied after the catalysts calcined at different temperatures. The catalysts were characterized by X-ray diffraction (XRD), specific surface area measurements (BET), oxygen storage capacity (OSC), and temperature programmed reduction (H₂-TPR). The results indicated that the catalyst supported on ZrO₂-TiO₂ had excellent stability at high temperature, and possessed high specific surface area and oxygen storage capacity, and had strong redox property. The results of the catalytic activities indicated that the monolith manganese-based catalyst using ZrO₂-TiO₂ as support had evidently improved the activity of NH₃-SCR reduction reaction at low temperature, and it showed great potential for practical application.