含钛MCM—41分子筛的合成与表征

水热法合成了含钛的ＭＣＭ－４１型超大孔分子筛，通过ＸＲＤ，ＩＲ，ＤＲＳＵＶ－ＶＩＳ，＾２９ＳｉＭＡＳＮＭＲ等测试，表明钛处在分子筛骨架上，同时考察了Ｎａ＾＋、Ａｌ＾３＋对ＴｉＭＣＭ－４１合成的影响以及分子筛的热稳定性、吸附量和催化活性。     

STUDY ON CARBOXYL-CONTAINING STARCH IN HEAVY METAL REMOVAL

ＳＴＵＤＹＯＮＣＡＲＢＯＸＹＬ－ＣＯＮＴＡＩＮＩＮＧＳＴＡＲＣＨＩＮＨＥＡＶＹＭＥＴＡＬＲＥＭＯＶＡＬ￥ＺｈｏｎｇＡｉＨＵ，ＸｉｎＸｉｎＺＨＯＵ，ＬｉＺＨＡＮＧ，ＹｕｅＨｕａＧＵＯ，ＨｏｎｇＹｉｎｇＷＵ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ．Ｎ...     

DICHLORODIMETHYLSILANE－A USEFUL REAGENT FOR THE CLEAVAGE OF PEPTIDYL WANG RESIN

ＤＩＣＨＬＯＲＯＤＩＭＥＴＨＹＬＳＩＬＡＮＥ－ＡＵＳＥＦＵＬＲＥＡＧＥＮＴＦＯＲＴＨＥＣＬＥＡＶＡＧＥＯＦＰＥＰＴＩＤＹＬＷＡＮＧＲＥＳＩＮ￥ＤｅＸｉｎＷＡＮＧ；ＹｉｎｇＳＵＮ；ＧｕｉＳｈｅｎＬＵａｎｄＱｉｎｇＣｈａｉＸｕ（ＩｎｓｔｉｔｕｔｅｏｆＭａ...     

以Nd改性CeO2-ZrO2固溶体助剂的研究

 用两种方法在贵金属三效催化剂的主要助剂CeO2－ZrO2固溶体中掺杂Nd进行改性,以提高催化剂的活性和热稳定性．方法1是采用硝酸钕溶胶浸渍CeO2－ZrO2固溶体的新方法,试图在固溶体粉体外层分别附上含Nd的物质．方法2为用改进的溶胶－凝胶法制备出均一相的含Ce,Zr和Nd的三组分超细固溶体．测定了样品的比表面积和储氧量,并对部分样品进行了XRD和H2－TPR表征．结果表明,用方法1制备的复合相超细粒子的热稳定性优于用方法2制备的均一相超细固溶体,且当Nd含量为7％时,储氧量最高、热稳定性最佳．将经方法1改性过的以及未经Nd改性的CeO2－ZrO2固溶体,分别用机械混合的方法加入γ－Al2O3粉体制成催化剂前体,并进一步制成含低含量Pt,Pd和Rh的贵金属催化剂．活性测试结果表明,对于新鲜催化剂,经Nd改性后CO,C3H6和NO起燃温度下降20～30℃．经850℃老化2h后,和未掺杂Nd的催化剂的起燃温度相比,NO的起燃温度稍有下降,C3H6的起燃温度相差不大,而CO的起燃温度有所升高．     

ORIENTATIONAL RELAXATION IN GDEST－HOST AMORPHOUS POLYMERS WITH DEFFERENT GLASS TRANSITION TEMPERATURE

ＯＲＩＥＮＴＡＴＩＯＮＡＬＲＥＬＡＸＡＴＩＯＮＩＮＧＤＥＳＴ－ＨＯＳＴＡＭＯＲＰＨＯＵＳＰＯＬＹＭＥＲＳＷＩＴＨＤＥＦＦＥＲＥＮＴＧＬＡＳＳＴＲＡＮＳＩＴＩＯＮＴＥＭＰＥＲＡＴＵＲＥ￥ＬｉＸｉｎＺＨＥＮＧ；ＴｉａｎＬｕＣＨＥＮ；ＤｅＬｉＷＡＮＧ；Ｘｉ...     

A NOVEL REACTION BETWEEN Ge－Ge AND Fe－Fe BONDS IN COMPLEX （Me_2GeGeMe_2）［（η~5－C_5H_4）Fe（CO）］_2（μ－CO）_2 AND CRYSTAL STRUCTURE OF THE PRODUCT

ＡＮＯＶＥＬＲＥＡＣＴＩＯＮＢＥＴＷＥＥＮＧｅ－ＧｅＡＮＤＦｅ－ＦｅＢＯＮＤＳＩＮＣＯＭＰＬＥＸ（Ｍｅ_２ＧｅＧｅＭｅ_２）［（η~５－Ｃ_５Ｈ_４）Ｆｅ（ＣＯ）］_２（μ－ＣＯ）_２ＡＮＤＣＲＹＳＴＡＬＳＴＲＵＣＴＵＲＥＯＦＴＨＥＰＲＯＤＵＣＴ￥ＸｉｕＴ?..     

六方介孔硅酸盐的制备,表征及对苯酚羟化反应的催化作用

在室温下制备了Ｃｕ－ＨＭＳ（六方介孔硅酸盐）介孔含Ｃｕ杂原子分子筛，利用ＸＲＤ、ＩＲ和ＥＳＲ对其进行了表征，表明Ｃｕ原子已进入硅酸盐骨架．探讨了这种新型杂原子分子筛对苯酚羟化反应的催化作用，发现Ｃｕ－ＨＭＳ与Ｖ－ＨＭＳ，Ｔｉ－ＨＭＳ，ＴＳ－１，Ｃｕ－ＺＳＭ－５和Ｃｕ－Ｙ相比，具有较高的催化活性．研究了反应介质及ｐＨ值对苯酚羟化反应的影响，并给出了相应的反应机理     

PREPARATION OF BAGASSE XANTHATES （BX） AND NICKEL REMOVAL FROM WASTEWATER BY BX

ＰＲＥＰＡＲＡＴＩＯＮＯＦＢＡＧＡＳＳＥＸＡＮＴＨＡＴＥＳ（ＢＸ）ＡＮＤＮＩＣＫＥＬＲＥＭＯＶＡＬＦＲＯＭＷＡＳＴＥＷＡＴＥＲＢＹＢＸＺｈｏｎｇＣｈａｎｇｇｅｎｇ；ＴａｎｇＤｏｎｇｇｏｎｇ；ＣｈｅｎＱｉａｏｙｕｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓ...     

含铈、镧低贵金属含量三效催化剂的结构与性能

采用ＣｅＯ２和Ｌａ２Ｏ３的不同加入方式,制备了一系列以ＣｅＯ和Ｌａ２Ｏ３为助剂的低贵金属含量三效催化剂,用ＸＲＤ和ＸＰＳ对其结构进行了表征,并进行了孔结构测定。测试了样品上ＣＯ,Ｃ３Ｈ６和ＮＯｘ三效转化的温度－转化率曲线和Ｓ值－转化率曲线。结果表明：以机械混合加入ＣｅＯ２和Ｌａ２Ｏ３的样品抗烧结性能差,老化后在Ｓ≤１区的ＮＯｘ和Ｃ３Ｈ４转化率明显下降,但起燃温度并不高;     

氧化铈对F-T反应铁锆催化剂的助催化作用

应用ＸＲＤ、ＸＰＳ、Ｍｏｓｓｂａｕｅｒ谱、ＴＰＲ、ＣＯ－ＴＰＤ、ＣＯ＋Ｈ２反应性能测量试等手段研究了ＣｅＯ２对Ｆ－Ｔ合成制低碳烯烃Ｃｅ－Ｆｅ／ＺｒＯ２催化剂催化性能的影响。结果表明，与Ｆｅ／Ｚｒ催化剂相比，加铈助剂后的催化剂Ｆ－Ｔ反应催化活性明显上升。     

添加稀土氧化物助剂的CeO2-ZrO2固溶体的储氧性及热稳定性研究

大多数工业催化剂都是在稳定的操作条件下进行的,然而汽车尾气净化催化剂却被暴露在大气中,使用条件经常变化,尤其是空燃比(A/F)的变化,直接影响了对氧敏感的三效催化剂的氧化和还原性能[1].CeO2则是一种具有储氧/释氧能力的催化材料,它作为助剂加入三效催化剂中,可在贫况下储存氧(以Ce4+存在)利于NOx的还原,在富况下释放氧(以Ce3+存在),利于HC、CO的氧化,从而提高了催化剂的活性.然而,CeO2 的储氧性通常局限在表面上,当温度超过400℃以上时,其比表面积降低从而引起储氧性能急剧下降,直接影响催化剂的性能和寿命.     

FeOx／ZrO2催化剂结构及CO氧化性能的研究

利用XRD、TPR及固定床微反技术,研究了添加FeOx对ZrO2载体结构稳定性和催化性能的影响。结果表明,FeOx对载体ZrO2具有良好的热稳定性,能阻止ZrO2从四方晶型向单斜晶型的转变;FeOx与载体ZrO2之间的相互作用,能促进FeOx在载体表面的分散,并提提高FeOx/ZrO2催化剂的氧化和还原性能。     

Ce-Zr-O固溶体的制备和表征

采用硝酸盐直接分解法、共沉淀法、苹果酸溶胶 凝胶法和柠檬酸溶胶 凝胶法制备了Ce Zr O复合氧化物并进行了表征。溶胶 凝胶法制得的Ce Zr O为立方的Ce0 .5Zr0 .5O2 复合氧化物 (其中少量具有立方性质的t″相 ) ,而直接分解和共沉淀法制得的是由立方Ce0 .8Zr0 .2 O2 和四方Ce0 .2 Zr0 .8O2 固溶体组成的复合氧化物。不同制备方法制得的样品由于物相组成不同 ,还原性能也有较大差别。差热分析和X射线衍射分析结果表明 ,凝胶在燃烧的同时生成了Ce0 .5Zr0 .5O2 固溶体。     

负载型Pd三效催化剂：载体CeO2-ZrO2-BaO的制备及催化性能

制备了不同BaO含量的CeO2-ZrO2储氧材料,并以此材料为载体浸渍H2PdCl6制得三效催化剂.结果表明,不论新鲜还是1 000 ℃老化状态下,以10%BaO添加CeO2-ZrO2储氧材料制备的Pd三效催化剂活性最佳,起燃和完全转化温度最低.XPS结果证实,10%BaO添加.通过稳定PdO活性组分并改变其电子环境使得催化剂有最佳活性.而随着BaO含量持续增加,Pd活件组分相对处于较氧化状态.储氧量、低温N2吸附-脱附测试以及XRD测试结果均表明10%BaO添加的材料储氧量,比表面积以及孔容均最大,而且有适应三效催化的孔径.这些结果均有助于以其制备的Pd三效催化剂获得更好的活性以及热稳定性.     

铈和镧改性γ-Al2O3担载Pd催化剂的结构效应

分别以镧-铈、铈-镧顺序浸渍和镧铈共浸渍的方式在γ-Al2O3载体上引入助剂La2O3和CeO2，然后担载Pd制备了一系列催化剂.以甲醇分解为探针反应，采用XRD、EXAFS和XPS对催化剂的体相和表面结构进行表征，用BET法测定比表面积，并进行了吸附态CO的FTIR研究.结果表明,La2O3容易进入CeO2的晶格中，促进了CeO2在γ-Al2O3上的分散.但不同的La2O3、CeO2加入方式对活性组分Pd在改性载体上的分散度、优势暴露面及其与CeO2之间的相互作用产生不同的影响.关联甲醇分解性能测试结果说明,Pd在载体上的高度分散以及Pd和CeO2之间通过界面产生的强相互作用是催化剂具有高活性的关键.     

掺杂Mn对CeO2-ZrO2-Al2O3材料性质的影响

采用共沉淀法制备了一系列Mn掺杂摩尔分数为0～5%的CeO2-ZrO2-Al2O3(CZA)复合氧化物, 并采用BET, OSC, XRD, XPS, H2-TPR等方法对所制备的材料进行了表征. 结果表明, 所制备的材料均形成了稳定的CZA固溶体, 尤其是Mn掺杂0.5%的材料在600和1000 ℃焙烧后均表现出最好的织构性能. OSC和H2-TPR的结果表明, Mn掺杂量≤1%时, 氧在材料中的体相移动是材料储氧和被还原的速控步骤, 并且Mn的掺杂量为0.2%时, 储氧量最大, 材料的还原温度也最低; Mn掺杂量>1%时, Mn物种对材料储氧和被还原的作用显著. XPS结果表明, Mn在焙烧过程中会迁移向表面, 结合H2-TPR结果可知, 新鲜样品表面的MnOx物种主要为Mn2O3, 而老化样品主要为Mn3O4.     

Autothermal reforming of methane over Ni catalysts supported over ZrO2-CeO2-Al2O3

Ni catalysts supported on Al2O3, ZrO2-Al2O3, CeO2-Al2O3 and ZrO2-CeO2-Al2O3 were prepared by coprecipitation method, and their catalytic performances for autothermal reforming of methane to hydrogen were investigated. The Ni-supported catalysts were characterized by XRD, TPR and XPS. The relationship between the structures and catalytic activities of the catalysts was discussed. The results showed that the catalytic activity and stability of the Ni/ZrO2-CeO2-Al2O3 catalyst was better than those of other catalysts with the highest CH4 conversion, H2/CO and H2/COx ratio at 750 ℃. The catalyst showed a little deactivation along the reaction time during its 72 h on stream with the mean deactivation rate of 0.08%/h. The catalytic performance of the Ni/ZrO2-CeO2-Al2O3 catalyst was also affected by reaction temperature, no2 ： nCH4 molar ratio and nH2O ： nCH4 molar ratio. TPR, XRD and XPS measurements indicated that the formation of ZrO2-CeO2 solid solution could improve the dispersion of NiO, and inhibit the formation of NiAl2O3, and thus significantly promoted the catalytic activity of the Ni/ZrO2-CeO2-Al2O3 catalyst.     

Doping of Ceria-Zirconia Solid Solution with Rare-earth Elements

The increasingly restrictive regulations on car exhaust emissions will necessitate the development of a new generation of three way catalysts (TWC) with better performance1. Ceria (CeO2) is the main component of the current TWC: its key role is to compensate the fluctuations in the exhaust stream composition, therefore, allowing to expand the air/fuel(A/F) operating window of catalytic converters2. This property is related to its oxygen storage capacity (OSC), associated to the redox couple Ce4+/Ce3+. However, CeO2 alone is easy to sinter to lost OSC at high temperature3.Ceria-zirconia (CexZr1-xO2) solid solutions by incorporation of Zr4+ in the CeO2 lattice have enhanced OSC and greater thermal stability, which are becoming the key materials for the new generation of TWC4. OSC of ceria-zirconia solid solutions can be further improved by the addition of M3+ dopants5. Besides Ce, other rare-earth elements such as Pr and Tb can vary their oxidation state. Pr and Tb are particularly suitable for making solid solutions with cerium because the known structure of PrO2 and TbO2 is of the cubic fluorite type, and the ionic radii of Pr4+ and Tb4+ are close to that of Ce4+6.In this paper, Ce0.6Zr0.3M0.1O2 (M=Y, La, Pr, Tb) were prepared by co-precipitation technique and characterized by a series of methods. Meanwhile, palladium-only TWCs were prepared by slurry coating and their catalytic activity was evaluated under the condition of simulated exhaust in the lab.XRD and FT-Raman spectra results show Ce0.6Zr0.3M0.1O2 have cubic fluorite structure which keep unchanging at high temperature. The different dopant ion radii brought different effect on the cell parameter of Ce0.6Zr0.3M0.1O2. The X-ray photoelectron spectroscopy (XPS) results show that the binding energy of Ce3d, Zr3d and O1s for Ce0.6Zr0.3M0.1O2 rose compared with that for Ce0.6Zr0.4O2, indicating dopant elements changed chemistry environment of solid solutions which was available to improve redox performance From TPR results, doping La can not change redox performance of solid solution, but doping Y decreased reduction temperature. Doping Pr and Tb notably improved redox performance of solid solutions due to appearance of low-temperature reduction peak in TPR profile which come from mobility of bulk oxygen.Compared with Pd/Ce0.6Zr0.4O2, doping Y and La unchanged A/F characteristic of TWCs, but doping Pr and Tb widen A/ F operating window and make HC, CO and NO have higher conversion.The light-off temperature of Pd/Ce0.6Zr0.3La0.1O2 was corresponded to that of Pd/Ce0.6Zr0.4O2.However, the light-off temperatures of Pd/Ce0.6Zr0.3M0.1O2 (M=Y, Pr, Tb) were lower than that of Pd/Ce0.6Zr0.4O2, which kept much lower after high temperature treatments. Among Pd/Ce0.6Zr0.3M0.1O2 (M=Y, La, Pr, Tb), Pd/Ce0.6Zr0.3Tb0.1O2 showed wider A/F operating window,higher conversion, lower light-off temperature and better high-temperature resistance     

共沉淀法制备的CeO2-ZrO2-Al2O3材料及性能

采用简单易操作的共沉淀法制备了性能优异的CZA材料, 并通过对其晶体结构的表征, 初步探讨了ZrO2和Al2O3在CZA中的存在方式.     

CeO2-ZrO2-La2O3-Al2O3 composite oxide and its supported palladium catalyst for the treatment of exhaust of natural gas engined vehicles

Composite supports CeO2-ZrO2-Al2O3 (CZA) and CeO2-ZrO2-Al2O3-La2O3 (CZALa) were prepared by co-precipitation method. Palladium catalysts were prepared by impregnation and their purification ability for CH4, CO and NOx in the mixture gas simulated the exhaust from natural gas vehicles (NGVs) operated under stoichiometric condition was investigated. The effect of La2O3 on the physicochemical properties of supports and catalysts was characterized by various techniques. The characterizations with X-ray diffraction (XRD) and Raman spectroscopy revealed that the doping of La2O3 restrained effectively the sintering of crystallite particles, maintained the crystallite particles in nanoscale and stabilized the crystal phase after calcination at 1000 ℃. The results of N2-adsorption, H2-temperature-programmed reduction (H2-TPR) and oxygen storage capacity (OSC) measurements indicated that La2O3 improved the textural properties, reducibility and OSC of composite supports. Activity testing results showed that the catalysts exhibit excellent activities for the simultaneous removal of methane, CO and NOx in the simulated exhaust gas. The catalysts supported on CZALa showed remarkable thermal stability and catalytic activity for the three pollutants, especially for NOx. The prepared palladium catalysts have high ability to remove NOx, CH4 and CO, and they can be used as excellent catalysts for the purification of exhaust from NGVs operated under stoichiometric condition. The catalysts reported in this work also have significant potential in industrial application because of their high performance and low cost.