铜基氧化锆载体合成甲醇催化剂的结构表征

以ＸＲＤ，ＥＸＡＦＳ和ＥＳＲ等手段考察了ＣｕＯ／ＺｒＯ２催化剂及其还原态的结构，结果表明，在ＣｕＯ／ＺｒＯ２中铜以ＣｕＯ的形式存在，ＺｒＯ２载体对所负载的ＣｕＯ的结构有影响，ＣｕＯ的分散度与焙烧温度有关，在适当的温度下焙烧，负载于ＺｒＯ２上的ＣｕＯ可自发分散，在还原态试样中铜主要以有金属的形式存在，但是当试样中铜的含量小，铜的分散度高时有铜的氧化物存在，其Ｃｕ－Ｏ键距介于ＣｕＯ与ＣｕＯ２之间，Ｃｕ     

CuO在ZrO2上的分散状态及其对催化性能的影响

用ＸＲＤ、ＴＰＲ和ＴＰＤ－ＭＳ等手段表征了浸渍法制备的ＣｕＯ／ＺｒＯ２催化剂，发现ＺｒＯ２上高度分散的氧化铜具有显著的易被还原和再氧化的特性，从而催化剂具有高的ＣＯ氧化活性。     

CuO／ZrO_2超细粒子催化剂的制备和物性结构表征Ⅱ．煅烧温度的影响

ＣｕＯ／ＺｒＯ２超细粒子催化剂的制备和物性结构表征Ⅱ．煅烧温度的影响师江柳刘金尧朱起明（清华大学化学系一碳化工国家重点实验室，北京１０００８４）张鎏张继炎（天津大学化工系，天津３０００７２）关键词氧化铜，氧化锆，超临界流体干燥，超细粒子，煅烧，物性结...     

氧化铈气凝胶担载氧化铜催化剂的TPR研究

 采用程序升温还原研究了氧化铈气凝胶担载氧化铜催化剂的还原行为,并与其对一氧化碳氧化反应的催化活性进行了关联．发现此类催化剂中存在两种类型的氧化铜,即体相氧化铜和分散于载体表面的氧化铜,且后者中的部分氧化铜还原后易被氧化．随着此易被氧化的铜含量的增加,催化剂对一氧化碳氧化反应的催化活性升高,表明此种类型的铜为催化剂的活性组分．     

焙烧温度对CuO/Fe2O3/ZrO2甲醇水蒸气重整制氢催化剂性能的影响

采用XRD、TPR和EXAFS等手段，考察了焙烧温度对CuO/Fe2O3/ZrO2物化性能和甲醇水蒸气重整制氢活性及其选择性的影响。结果表明，催化剂中氧化铜的晶粒随着焙烧温度的提高而增大，铜的配位环境发生变化。在焙烧温度623K－723K范围内，对甲醇水蒸气重整反应的甲醇转化率和氢选择性影响较小，其结构参数变化值较小。当焙烧温度提高到923K时，催化剂的活性因ZrO2晶化和铜组分的聚焦而显著降低。结果铁的加入使ZrO2的相变温度向后推移，并且有效地阻止了CuO颗粒的聚集。     

Study of a Ru-La/Zr02 Catalyst Prepared by Precipitation Method for Selective Hydrogenation of Benzene to Cyclohexene

A Ru-La/ZrO2 catalyst was prepared by the precipitation method, in which Ru was an active component, La was a promoter and ZrO2 was a dispersant. Comparing with the catalyst prepared by the chemical reduction method, the Ru-La/ZrO2 exhibited higher activity and better selectivity. At 140 ℃ and hydrogen pressure of 5 MPa, the C6H10 selectivity reached 70% at a C6H6 conversion of 35% for a reaction time was 5 min and the total La/Ru loading was 10%. Textural parameters of the catalyst were obtained by physical adsorption, BET surface area and specific pore volume measurements. The catalyst sample gave a BET area of 41 m2/g and a specific pore volume of 1.1 cm^3/g, and the most probable pore distribution was located at 5 to 10 nm. H2-TPR measurements showed that ruthenium oxide could be reduced to its metallic state at about 403 K. XRD determinations indicated that ruthenium and lanthanum were highly dispersed on the zirconia. A significant advantage of the Ru-La/ZrO2 catalyst is that it can be used directly in its unreduced state for the selective hydrogenation of benzene.     

Study of a Ru-La/ZrO_2 Catalyst Prepared by Precipitation Method for Selective Hydrogenation of Benzene to Cyclohexene

1. Introduction Cyclohexene as an important intermediate prod- uct is widely used in chemical productions. The process of selective hydrogenation of benzene to cyclo- hexene has been an important research topic in green chemistry owing to its atomic economy and clean production [1]. In order to attain greater economic benefits, researchers are searching for a new catalytic system that is high in activity and selectivity, simple in technology, and low in cost. In this respect, some progresses h…     

焙烧温度对Cu/ZrO2和Cu-La2O3/ZrO2催化性能的影响

Cu／ZrO2催化剂作为一种新型的甲醇合成催化剂,和Cu-Zn-Al催化剂相比,具有优良的催化活性[1,2]．Cu／ZrO2催化剂中活性中心及合成甲醇的反应机理与Cu-Zn-Al催化剂有较大差别,铜锆分散度及界面大小对甲醇合成活性有重要影响,如Keoppel等人研究发现,当Cu／ZrO2催化剂焙烧温度达到923K,ZrO2发生晶化,严重影响铜锆界面从而显著降低催化剂的活性[3]．ZrO2作为p型半导体,在催化剂中不仅起对催化剂活性组分进行支撑和分散作用,它可与催化剂活性组分产生独特的相互作用．近年来,铜锆之间的相互作用及协同效应日益受到人们重视[4…     

Characterization and catalytic functionalities of copper oxide catalysts supported on zirconia

A series of zirconia supported copper oxide catalysts with varying copper loadings (1.2-19.1 wt %) were prepared by impregnation method. The catalysts were characterized by X-ray diffraction, UV-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and temperature-programmed desorption of CO2. Copper dispersion and metal area were determined by N2O decomposition method. X-ray diffraction patterns indicate the presence of crystalline CuO phase beyond 2.7 wt % of Cu on zirconia. UV-visible diffuse reflectance spectra suggest the presence of two types of copper species on the ZrO2 support. XPS peaks intensity ratio of Cu 2p3/2 and Zr 3d5/2 was compared with Cu dispersion calculated from N2O decomposition. TPR patterns reveal the presence of highly dispersed copper oxide at lower temperatures and bulk CuO at higher temperatures. The basicity of the catalysts was found to increase with Cu loading, and the activity of the catalysts was also found to increase with the increase in Cu loading up to 2.7 wt % Cu loading. The catalytic properties were evaluated for the dehydrogenation of cyclohexanol to cyclohexanone and were related to surface properties of the copper species supported on zirconia.     

VOx/ZrO2和K-VOx/ZrO2催化剂的结构与催化碳黑氧化性能

采用等体积浸渍法制备两个系列不同V和K负载量的VOx/ZrO2和K-VOx/ZrO2催化剂.利用程序升温氧化反应(TPO)技术对VOx/ZrO2和K-VOx/ZrO2催化碳黑氧化的活性进行了考察.实验结果表明,当催化剂中V的负载量nV/nZr=4/100时, VOx/ZrO2催化剂的活性最好.添加K能显著改善VOx/ZrO2催化剂的活性,当K的添加量为nK∶nV∶nZr=1∶4∶100时,碳黑氧化的反应温度最低.催化剂的红外光谱和紫外-可见光谱表征的结果表明, nV/nZr=4/100时,催化剂的表面形成聚合的V物种浓度最大.由于聚合的V物种具有较强的氧化还原能力,因而能显著地降低柴油碳黑的氧化温度.当K-VOx/ZrO2催化剂中nK/nV超过1/4时,由于形成KVO3物种,催化剂表面原子的移动性减弱,因而催化活性降低.