共查询到20条相似文献,搜索用时 78 毫秒
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选用Si3N4,AlN,Al2O3和Sn2O3(或Nd2O3)粉末为原料,在1800~1950℃的温度范围内,1.0~3.0MPa氮气压力下烧吉(GPS),制备了性能优良的Re-α/β-Sialon(Re=Nd,Sm)陶瓷材料,利用XRD,EDS,TEM和EREM手段研究了材料的相组成,显微结构特性与其性能的关系。结果表明,其主晶相为长柱状的β-Silaon和近似等轴的Re-α-Sialon,晶界 相似文献
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选用工业堇青石和γ-Al2O3作载体,用浸渍法制取了两类负载型水汽变换反应催化剂。X-射线衍射(XRD)分析结果表明:载于堇青石载体表面的负载成份确实形成了钙钛矿型氧化物LaFeO3;而在γ-Al2O3载体上未观察到LaFeO3等晶体化合物。两种载体的性质不同,使得这两类负载型催化剂中活性组份存在的晶态不同,致使堇青石作载体的催化剂,其变换活性明显高于γ-Al2O3作载体的催化剂 相似文献
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进行了Al(OH3)→α-Al2O3转化过程中的相变研究及V-Al(OH)3中的V-Al2O3的红外光谱定量工作,对提高多品种氧化铝生产的质量具有重要意义。 相似文献
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通过对 Sr4 Al14 O25∶ Eu , Nd 夜光粉 样品的 X 射线衍射 分析,确 定其是一 混晶结 构。 Eu 2 +取代基质 中 Sr2 + 的位 置, Nd3 + 取代 Al3 + 的位置 。通过 扫描电 镜测定 了样 品的 外观 形貌 和颗 粒级配。 相似文献
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Intragranular Rare Earth-rich Phases in As-cast High-temperature Ti-5Al-4Sn-2Zr-1MO-0.25Si-1Nd Alloy
IntragranularRareEarth-richPhasesinAs-castHigh-temperatureTi-5Al-4Sn-2Zr-1MO-0.25Si-1NdAlloyLiGeping(李阁平);LiDong(李东);LiuYuyin... 相似文献
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CalculationofRECl_3-CaCl_2-LiClPhaseDiagrams(RE=La,Ce,Pr,Nd)QiaoZhi-Yu(乔芝郁);XingXian-Ran(邢献然),DuanShu-Zhen(段淑贞)(DepartmentofPh... 相似文献
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RECl_3与Gly间配合行为的半微量相平衡研究 总被引:5,自引:1,他引:4
测定了RECl_3-Gly-H2_O(RE=Sm,Dy,Yb)三元体系在25℃时的溶度和饱和溶液折光率,绘制了相应的溶度图和饱和溶液折光率曲线。各体系的溶度曲线与折光率曲线均由四支组成,分别与RECl_3·6H_2O,RE(Gly)Cl_3,2H_2O,RE(Gly)_3Cl_3·3H_2O和Gly相对应。制备了5个未见文献报道的化合物:RE(Gly)_3Cl_3·3H_2O(RE=Ce,Pr,Nd,Sm,Dy),并用化学分析、元素分析、IR、FS、X-粉末衍射和TG-DTG对其进行了表征。 相似文献
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Perovskite oxide LaMnO3 was prepared by sol-gel method and the nanosize Au/LaMnO3 catalyst was prepared by deposition-precipitation(DP) method in the paper.Characterization of the catalyst sample was made by X-ray diffractometer(XRD),atom absorption spectra(AAS) and X-ray photoelectron spectroscopy(XPS) instrumental methods.The activity,long-term stability and the reasons for deactivation of the gold catalyst in CO oxidation were investigated.The experiment results demonstrated that the Au/LaMnO3 catalyst e... 相似文献
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通过浸渍-焙烧法制备了新型固体酸SO4^2-/MnO2/γ-Al2O3催化剂,以草酸和异戊醇为原料合成了草酸二异戊酯,考察了催化剂的焙烧温度、催化剂用量、原料配比、反应时间、带水剂甲苯用量对反应的影响。最佳的反应条件为:催化剂焙烧温度500℃、催化剂用量1.5g,n(草酸):n(异戊醇)=1:3、带水剂甲苯30mL、回流时间1.5h;在最佳反应务件下,草酸二异戊酯的收率可达99.6%。新型固体酸SO4^2-/MnO2/γ-Al2O3的催化活性高、产品收率高,后处理简便,无“三废”污染,符合节能环保、绿色催化的发展趋势。 相似文献
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Temperature programmed reduction (TPR) study was carried out for CeO2/A12O3 and CeO2/ZrO2 catalysts to evaluate oxygen storage property induced by a facile redox cycling of Ce ion. The CeO2/ZrO2 catalyst possesses excellent oxygen storage activity at 373 K after reduction above 1173 K although the oxygen storage of CeO2/Al2O3 catalyst after reduction above 1173 K is poor because of the formation of CeAlO3. Consequently, the oxygen storage on the CeO2/ZrO2 catalyst smoothly occurs from low temperatures when the catalyst is reduced even at high temperatures. 相似文献
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High thermal stable gold catalyst supported on La2O3 doped Fe2O3 for low-temperature CO oxidation 总被引:1,自引:1,他引:0
La2O3 doped Fe2O3 support was prepared by co-precipitation method,and gold was loaded by deposition-precipitation.Thermal stability of gold catalyst was enhanced considerably by La2O3 doping.Even when calcined at 500 oC for 12 h,the catalyst doped with La2O3 could convert 90% of CO at 28.9 oC,while the catalyst without La2O3 doping achieved 90% CO conversion at 43.5 oC.Characterization techniques,such as N2 adsorption-desorption,X-ray diffraction(XRD),transmission electron microscopic(TEM) and thermogravime... 相似文献
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SO2-4/TiO2-WO3催化合成环己酮1,2-丙二醇缩酮 总被引:3,自引:0,他引:3
介绍了以固体超强酸SO42-/TiO2-WO3为多相催化剂,通过环己酮和1,2-丙二醇反应合成了环己酮1,2-丙二醇缩酮,探讨了SO24-/TiO2-WO3对缩酮反应的催化活性,较系统地研究了酮醇量比,催化剂用量,反应时间诸因素对产品收率的影响.实验表明:SO24-/TiO2-WO3是合成环己酮1,2-丙二醇缩酮的良好催化剂,在n(环己酮):n(1,2-丙二醇)=1:1.5,催化剂用量为反应物料总质量的1.25%,环己烷为带水剂,反应时间1.5 h的优化条件下,环己酮1,2-丙二醇缩酮的收率可达88.5%. 相似文献
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Various affecting factors and degradation mechanism were studied on ultrasonic degradation of methyl orange adopting Y2O3 doping anatase TiO2 catalyst prepared in laboratory.In the experiment, the UV-VIS spectrophotometer was used to follow and inspect the degradation process of methyl orange.The results indicate that the ultrasonic degradation ratios of methyl orange in the presence of anatase TiO2 catalyst are much better than those without catalyst.Moreover, the catalytic performance of Y2O3 doping anatase TiO2 catalyst is obviously higher than that of anatase TiO2 catalyst without doping.The optimal conditions were adopted in this work and the degradation and COD elimination ratio of methyl orange got to98% and 99.0% in 90 min, respectively. 相似文献
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Cu-Fe Catalysts Modified by Rare Earths for Preparation of High Alcohols from Fatty Acid Esters Reduction 相似文献
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通过超声浸渍法,经Ce3+和Ag+协同改性磷钨杂多酸(HPW)制备了一种以Lewis酸性活性位为主的固体酸催化剂Ce-Ag-PW。采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)、透射电镜(TEM)、热重(TG)、NH3程序升温脱附(NH3-TPD)、吡啶吸附红外光谱(Py-IR)和X射线光电子能谱(XPS)等表征手段对其物理化学性能进行了表征分析。并以Ce-Ag-PW为经甲醇和油酸酯化反应来合成生物柴油的催化剂,对其的催化活性和稳定性进行了研究。结果表明,Ce-Ag-PW具有高催化活性和稳定性,以其为催化剂,当甲醇与油酸的物质的量比为14: 1,催化剂用量为反应物总质量的2%,反应温度为65 ℃,反应6 h后,油酸的转化率即高达91%。固体酸催化剂在经过4次循环使用后,油酸的转化率仍可达到80.5%。Ce-Ag-PW的高催化活性和稳定性可归因于Ag+可置换HPW中的质子,以及Ce3+的强吸电子作用,使其由Br?nsted酸型催化剂转化为以Lewis酸型为主的催化剂。由于Br?nsted酸位易与酯化反应过程中生成的水发生水合反应而失活,因而Lewis酸位的形成有助于减少催化剂的失活现象发生。因此,当通过油酸与甲醇酯化反应合成生物柴油时,Ce-Ag-PW是一种具有高催化活性和稳定性的以Lewis酸性活性位为主的固体酸催化剂。 相似文献