制备高碳醇用Cu－Fe系催化剂的活性相

用共沉淀法制备了Ｃｕ－Ｆｅ系催化剂，它是由脂肪酸甲酯加氢制备高碳醇的新催化体系．催化剂经焙烧后的物相为ＣｕＯ，γ－Ｆｅ２Ｏ３和ＭｇＯ，形成了活性相的结构前驱．在反应条件下，ＣｕＯ首先被还原为金属态的Ｃｕ０，然后γ－Ｆｅ２Ｏ３被还原为Ｆｅ３Ｏ４；Ｃｕ０和Ｆｅ３Ｏ４共同参与催化该反应．本文用ＸＲＤ，ＴＧ－ＤＴＡ和Ｍｏｓｓｂａｕｅｒ谱等手段，结合催化剂的活性测定，确定了催化剂的活性相为Ｃｕ０和Ｆｅ３Ｏ４；ＭｇＯ可改变催化剂的电子结构和几何构型，起到重要的助催化作用     

用MES及XRD研究FT合成催化剂的活性结构

采用穆斯堡尔谱及Ｘ光衍射法研究了共沉淀法制备的不同Ｆｅ／Ｍｎ比催化剂在焙烧、合成气还原及ＦＴ反应后体系相结构的变化。结果表明：锰助剂的加入使催化本相由铁磁性逐渐转化为超顺磁性，相应使催化剂还原逐渐难，Ｍｎ助剂促进了ＦＴ合成反应进行。反应性能与Ｆｅ／Ｍｎ尖晶石（Ｆｅ１－ｙＭｎｙ）３Ｏ４组成含量及式中ｙ大小密切相关，与ＭｎＣｏ３及ＭｎＯ的存在也有一定关系。富铁催化剂中Ｍｎ主要起电子助剂作用，而富锰催化     

（四甲基二硅撑）双（3－三甲硅基环戊二烯基）－四羰基二铁的反应性

标题化合物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２］_２／（μ－ＣＯ）_２（Ａ）分子中的Ｆｅ－Ｆｅ键被钠汞齐还原断裂，生成相应的双铁负离子，分别与ＭｅＣＯＣｌ、ＰｈＣＯＣｌ、ＰｈＣＨ_２Ｃｌ、ＣｌＣＨ_２ＣＯＯＣ_２Ｈ_５和Ｐｈ_３ＳｎＣｌ进行亲核取代反应，生成在铁原子上引入相应取代基的产物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２Ｒ］_２（Ｒ：ＭｅＣＯ（１），ＰｈＣＯ（２），ＰｈＣＨ_２（３），ＣＨ_２ＣＯＯＣ_２Ｈ_５（４），Ｐｈ_３Ｓｎ（５），Ｉ（６））。Ａ在氯仿中与碘反应，得到Ｆｅ－Ｆｅ断裂的双铁碘化物，但在苯中与过量碘反应，则得到Ｆｅ－Ｉ－Ｆｅ桥联的离子型化合物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２］_２Ｉ·Ｉ（７）。化合物６的晶体和分子结构经Ｘ射线衍射测定，６属单斜晶系，Ｐ２１／ｃ空间群，ａ＝１．７２１７（４）ｎｍ，ｂ＝０．７７５３（２）ｎｍ，Ｃ＝１．３６２９（７）ｎｍ，β＝１０３．８０（３）°，Ｖ＝１．７６７（２）ｎｍ３，Ｚ＝４，Ｄｃ＝１．６２９９·ｃｍ－１，最终偏差因子Ｒ＝０．０５４。     

环状配合物Me_2Si［η~5－C_5H_4Fe（CO）_2］_2SnR_2的合

通过ＳｎＣｌ_２对化合物Ｍｅ_２Ｓｉ［η~５－Ｃ_５Ｈ_４Ｆｅ（ＣＯ）］_２（μ－ＣＯ）_２（Ⅰ）中Ｆｅ－Ｆｅ键的插入反应以及Ⅰ被Ｎａ－Ｈｇ齐还原所生成的相应双铁负离子｛Ｍｅ_２Ｓｉ［η~５－Ｃ_５Ｈ_４Ｆｅ（ＣＯ）_２］_２｝~（２－）与ＳｎＲ_２Ｃｌ_２（Ｒ＝Ｍｅ，Ｐｈ）的亲核反应，合成了环状化合物Ｍｅ_２Ｓｉ［η~５－Ｃ_５Ｈ_４Ｆｅ（ＣＯ）_２］_２ＳｎＲ_２［Ｒ＝Ｃｌ（１），Ｍｅ（２），Ｐｈ（３）］。以元素分析、ＩＲ和~１ＨＮＭＲ谱表征了它们的结构，并用Ｘ射线衍射测定了配合物３的晶体结构。３为单斜晶系，空间群Ｐ２_１／ｎ，ａ＝１．０３８４（３）ｎｍ，ｂ＝１．６３８４（１）ｎｍ，ｃ＝１．５７６２（５）ｎｍ，β＝９７．９３（２）°，Ｖ＝２．６５６（２）ｎｍ~３，Ｚ＝４，Ｄｘ＝１．７１ｇ／ｍＬ。     

铁系无铬型CO高温变换催化剂的谱学研究

用Ｍｏｓｓｂａｕｅｒ谱，ＸＲＤ及ＴＥＭ技术对铁系无铬型催化剂的前驱态、母体及还原态在不同工艺条件下的生成及晶相结构的微变过程进行了研究。确证了水合四氧化三铁Ｆｅ３－ｘＯ４·ｎＨ２Ｏ和γ－Ｆｅ２Ｏ３晶态的形成，并探讨了晶相参数微变引起晶体结构的差异导致的催化活性的变化。在Ｆｅ３－ｘＯ４·ｎＨ２Ｏ中ＳＢ／ＳＡ比值为２，ｘ值接近于０时催化活性最高。     

钙钛矿型（La0.8M0.2）MnO2和（La0.2Sr0.2）（Mn1—xFex）O3的XRD和IR光谱 …

合成了（Ｌａ０．８Ｍ０．２）ＭｎＯ３和（Ｌａ０．８ｓＲ０．２）（ｍＮ１－ｘＦｅｘ）（Ｏ３（Ｘ＝０．１，０．２，０．３，０．４，０．５）两类氧化物，经ＸＲＤ确认为钙钛矿型氧化物，应用ＦＴ－ＩＲ对其进行研究，对主要的红外特征振动υ（Ｍｎ－Ｏ）和δ（Ｏ－Ｍｎ－Ｏ）进行了分析表征。     

固溶体α－（Fe_（1－x）Sb_x）_2O_3（0≤x≤0．2）气敏材料

用化学共沉淀法在ａ－Ｆｅ＿２Ｏ＿３，中掺入锑离子，Ｘ－射线衍射（ＸＲＤ）分析证实，锑离子可固溶于ｎ型半导体ａ－Ｆｅ＿２Ｏ＿３中形成ａ－（Ｆｅ＿１－ｘＳｂ＿ｘ）＿２Ｏ＿３（０《ｘ《０．２）固溶体。由于锑离子（Ｓｂ￣５＋）部分取代ａ－Ｆｅ＿２Ｏ＿３晶格中Ｆｅ￣３＋的格位，使得该系列材料的电导值增大一个数量级以上，气敏性能明显改善。     

氟碳铈精矿碳酸钠焙烧反应机制

采用ＸＲＤ、ＤＴＡＴＧ及化学分析法，研究了氟碳铈精矿碳酸钠焙烧反应。结果表明，焙烧过程中，发生Ｆ－＋Ｃｅ３＋（Ｐｒ３＋）→Ｏ２－＋Ｃｅ４＋（Ｐｒ４＋）的类质同象替代，生成ＲＥＯ１＋ｘＦ１－ｘ（０＜ｘ＜１）类质同象混晶体，在不同条件下，可生成不同组成的类质同象混晶体。从实验数据得到ＲＥＯ１＋ｘＦ１－ｘ类质同象混晶体的晶胞参数ａ０与其氟含量的关系式为：ａ０＝０５４４９＋０００１０２×ｃＦ－。     

氧缺位铁酸盐的制备及结构与还原行为的研究

在３５８Ｋ下用２００ｍｌ／ｍｉｎ的空气氧化碱性悬浮液合成了ＭＦｅ_２Ｏ_（４＋δ）（δ≥０，Ｍ＝Ｆｅ、Ｃｏ、Ｎｉ、Ｍｎ），并在５７３Ｋ下用４０ｍｌ／ｍｉｎ的Ｈ_２还原ＭＦｅ_２Ｏ_（４＋δ）制备了氧缺位铁酸盐ＭＦｅ_２Ｏ_（４－δ）（δ＞０）。用ＸＲＤ、Ｍｓｓｂａｕｅｒ谱等测试方法对铁酸盐的结构进行了表征，考察了铁酸盐的组成及第二金属组分（Ｃｏ、Ｎｉ、Ｍｎ）对铁酸盐还原性能的影响。在Ｈ_２还原３ｈ内，铁酸盐氧缺位程度随还原时间增加而增大，晶格常数也相应增大；５ｈ以上，铁酸盐将被还原为ＭＯ－ＦｅＯ或α－Ｆｅ，晶格常数几乎不变。按Ｆｅ、Ｃｏ、Ｎｉ、Ｍｎ顺序，ＭＯ与ＦｅＯ的相互作用能力、ＭＯ－ＦｅＯ固溶体的稳定性及铁酸盐还原为ＭＯ－ＦｅＯ的能力均增强，ＭＯ－ＦｅＯ进一步还原为α－Ｆｅ的能力却减弱。     

氧化铁在ZnO上分散的结构状态及其表征

采用（ＮＨ_４）_３［Ｆｅ（Ｃ_２Ｏ_４）_３］·ｘＨ_２Ｏ的水溶液含浸，Ｆｅ（ＮＯ_３）_３．９Ｈ_２Ｏ水溶液饱和浸渍（含浸）以及Ｆｅ（ＡｃＡｃ）_３的甲苯溶液热吸附三种方法制备了在ＺｎＯ上分散的氧化铁体系。用多种物理化学手段对用不同方法制备的分散体系进行了细致的表征，氧化铁在ＺｎＯ上形成单层分散是困难的。Ｆｅ~（３＋）一般进入到ＺｎＯ载体的表层，结构环境类似于ＺｎＦｅ_２Ｏ_４微晶中的Ｆｅ~（３＋），分散的Ｆｅ~（３＋）通常处于高自旋态，配位对称性并不是正交畸变。在ＺｎＯ上形成尖晶石的趋势最强。在亚单层铁含量范围内，通常形成表面ＺｎｘＦｅ_ｙＯ_ｚ。当铁含量超过单层阈值时，既生成ＺｎＦｅ_２Ｏ_４簇也有ＦｅＯ_ｘ簇存在。无论是ＦｅＯ_ｘ或ＺｎＦｅ_２Ｏ４簇还是表面的Ｚｎ_ｘＦｅ_ｙＯｚ，其Ｆｅ_（３＋）在实验温度范围内，很难被还原为零价铁，ＦｅＯ_ｘ较之Ｚｎ_ｘＦｅ_ｙＯ_ｚ物种难以还原且比体相ａ－Ｆｅ_２Ｏ_３中Ｆｅ~（３＋）要难还原得多。由热吸附法制得的ＦｅＯ_ｘ和ＺｎＦｅ_２Ｏ_４簇具有很低的催化活性，而由含浸法制得的表面Ｚｎ_ｘＦｅ_ｙＯｚ的反应性能有明显的改善。ＺｎＯ载体上不同含铁物种的反应性由Ｆｅ~（３＋）的还原性及是否存在活泼     

Mn_xCo_(3-x)O_4复合氧化物及改性催化剂催化分解N_2O

用共沉淀法制备了一组不同组成的MnxCo3-xO4尖晶石型复合氧化物,表面负载碱金属助剂制备改性催化剂,用于催化分解N2O.用X射线衍射(XRD)、N2物理吸附(BET)、红外光谱(FTIR)、扫描电镜(SEM)、H2程序升温还原(H2-TPR)、X射线光电子能谱(XPS)等技术表征催化剂结构.考察了复合氧化物组成、碱金属助剂类型、钾前驱物等制备参数对催化剂结构和催化活性的影响.结果表明:添加助剂K、Cs降低了催化剂表面Co、Mn元素的电子结合能,弱化了Co—O和Mn—O键,有利于氧物种的脱除,提高了催化剂活性.优化出了活性较高的催化剂K/Mn0.4Co2.6O4(K2CO3),有氧无水、有氧有水气氛400℃连续反应50 h,N2O转化率分别保持100%和74.2%,催化剂稳定性较高.     

A301氨合成催化剂的稳定性

合成氨工业是一个高能耗、高产值的产业,在化学工业中占有重要的地位.目前,合成氨工业的总趋势是朝着低(等)压、低能耗工艺方向发展,其核心技术之一是开发低(等)压、高活性的氨合成催化剂.七十年代以来国际上兴起了载钌催化剂的研究开发,目前已有工业化的报道[1].     

α-Fe2O3掺杂对In2O3电导和气敏性能的影响

用化学共沉淀法制备了α Fe2O3掺杂的In2O3纳米晶微粉,研究了α Fe2O3掺杂对In2O3电导和气敏性能的影响. 结果表明, α Fe2O3和In2O3间可形成有限固溶体In2－xFexO3(0≤x≤0.40); Fe3＋对In2O3晶格中In3＋格位的部分取代,大大增强了阴阳离子间的结合力,导致材料中氧空位VO×数骤降、 自由电子的浓度变稀和电导下降. n(Fe3＋):n(In3＋)=5 :5的共沉淀粉于800 ℃下灼烧4 h所得的α Fe2O3掺杂In2O3传感器元件,对45 μmol•L－1 C2H5OH的灵敏度达54.0,为相同浓度干扰气体汽油的8倍多.     

Fe-Mn/Al2O3催化剂低温 NH3选择性催化还原 NO的性能

本文制备了一系列 Fe-Mn/Al2O3催化剂,并在固定床上考察了其 NH3低温选择性催化还原 NO的性能.首先考察了不同 Fe负载量制备的催化剂的脱硝性能,优选出最佳的 Fe负载量;在此基础上,研究了 Mn负载量对催化剂脱硝效率的影响;最后,对优选催化剂的抗 H2O和抗 SO2性能进行了实验研究;同时,对催化剂由于 SO2所造成的失活机制进行了考察.采用 N2吸附-脱附、X射线衍射、透射电镜、能量弥散 X射线谱、程序升温还原、程序升温脱附、X射线光电子能谱、热重和傅里叶变换红外光谱等方法对催化剂进行了表征.结果表明,最佳的 Fe和 Mn负载量均为8%,所制的8Fe-8Mn/Al2O3催化剂在150°C的脱硝效率可达近99%;同时,在整个低温测试区间(90–210°C)的脱硝效率均超过了92.6%. Fe在催化剂表面主要以 Fe3+形态存在,而 Mn主要包括 Mn4+和 Mn3+; Mn的添加提高了 Fe在催化剂表面的积累,促进了催化剂比表面积增大和活性物种分散,改善了催化剂氧化还原性能和对 NH3的吸附能力.催化剂的高活性主要是由于其具有较大的比表面积、高度分散的活性物种、增加的还原特性和表面酸性、较低的结合能、较高的 Mn4+/Mn3+和增强的表面吸附氧.此外,8Fe-8Mn/Al2O3的催化性能受 H2O和 SO2影响较小,抗 H2O和 SO2能力较强.同时,反应温度对催化剂的抗硫性有重要影响,在较低的反应温度下,催化剂抗硫性更好; SO2造成催化剂活性降低主要是由于催化剂表面硫酸盐物种的生成.一方面,表面硫酸铵盐的生成造成催化剂孔道堵塞和比表面积降低,减少了反应中的气固接触从而导致活性降低;另一方面,催化剂表面的活性物种被硫酸化,造成反应中的有效活性位减少,从而降低了催化剂活性.     

Ni-Al类水滑石的制备及其Ni/Al2O3加氢脱硫研究

采用共沉淀方法合成了不同Ni/Al比的镍铝类水滑石,将其作为催化剂前驱体,制备了Ni/Al2O3加氢脱硫催化剂.通过X射线衍射法(XRD),程序升温还原(H2-TPR),热重分析(TG),傅里叶变换红外光谱(FT-IR)等技术对催化剂进行了表征.利用10 mL固定床装置在不同温度,压力,体积空速和氢油比条件下对Ni/Al2O3催化剂的加氢脱硫活性进行了评价.结果表明,XRD图和FT-IR图中均出现了Ni-Al类水滑石的特征峰,TG图呈现出两个明显阶段的失重,在Ni-Al2O3-HT的XRD图中最强的衍射角对应单质金属Ni粒子的(111)晶面.脱硫结果显示Ni-Al类水滑石作为前驱体在适当的条件下,FCC汽油的硫含量降至10 ppm以下.类水滑石作为前驱体的Ni/Al2O3加氢脱硫活性很好,说明类水滑石作为前驱体在加氢脱硫领域有好的应用前景.     

氢还原下铁钼催化剂的表面性质

用XPS对H_2还原下的铁钼催化剂的表面性质进行了研究。实验表明:H_2还原使表面钼离子由Mo~(6+)还原为Mo~(5+)和Mo~(4+),并与Fe~(3+)作用氧化为Mo~(6+);Fe~(3+)则由于与Mo~(5+)和Mo~(4+)作用以及H_2还原而变为Fe~(2+),从而形成了一个没有O_2存在,仅有H_2作用下的Mars-Krevelen氧化还原循环过程。在催化剂表面上生成的FeMoO_4,其Mo~(6+)的3d3/2和3d5/2的结合能值比Fe_2(MoO_4)_3中的Mo~(6+)的3d能级结合能值低。Mo(或Mo和Fe)离子键合的O~(2-)与H_2作用生成的Mo(Fe)-OH,其Os结合能的测定值低于键合于Mo(Fe)离子中的O~(2-)的Os结合能值,并且该结合能峰由于-OH间的相互作用结合成的水的脱附而消失。此外.给出了还原过程中H_2与催化剂表面O~(2-)相互作用的反应图式。     

Catalytic dehydration of ethanol using transition metal oxide catalysts

The aim of this work is to study catalytic ethanol dehydration using different prepared catalysts, which include Fe(2)O(3), Mn(2)O(3), and calcined physical mixtures of both ferric and manganese oxides with alumina and/or silica gel. The physicochemical properties of these catalysts were investigated via X-ray powder diffraction (XRD), acidity measurement, and nitrogen adsorption-desorption at -196 degrees C. The catalytic activities of such catalysts were tested through conversion of ethanol at 200-500 degrees C using a catalytic flow system operated under atmospheric pressure. The results obtained indicated that the dehydration reaction on the catalyst relies on surface acidity, whereas the ethylene production selectivity depends on the catalyst chemical constituents.     

Regenerable Fe-Mn-ZnO/SiO2 sorbents for room temperature removal of H2S from fuel reformates: performance, active sites, Operando studies

Fe- and Mn-promoted H(2)S sorbents Fe(x)-Mn(y)-Zn(1-x-y)O/SiO(2) (x, y = 0, 0.025) for desulfurization of model fuel reformates at room temperature were prepared, tested and characterized. Sulfur uptake capacity at 25 °C significantly exceeds that of both commercial unsupported ZnO sorbents and un-promoted supported ZnO/SiO(2) sorbents. Sulfur capacity and breakthrough characteristics remain satisfactory after multiple (～10) cycles of adsorption/regeneration, with regeneration performed by a simple and robust heating in air. XRD shows that both "calcined" and "spent" sorbents contain nano-dispersed ZnO, and XPS confirms conversion of ZnO to ZnS. "Calcined" sorbent contains Fe(3+) and Mn(3+) that are reduced to Mn(2+) upon reaction with H(2)S, but not with H(2). Operando ESR is used for the first time to study dynamics of reduction of Mn(3+) promoter sites simultaneously with measuring sulfidation dynamics of the Fe(x)-Mn(y)-Zn(1-x-y)O/SiO(2) sorbent. Fe cations are believed to occupy the surface of supported ZnO nanocrystallites, while Mn cations are distributed within ZnO.     

Preparation of Highly Active Pt-K/γ-AI203 Catalyst for 0-Phenylphenol Synthesis from 0-Cyclohexenyl-cyclohexanone Dehydrogenation

0.5%Pt-K/y-Al2O3 catalysts for the synthesis of 0-phenylphenol(OPP) from 0-cyclohexenyl-cyciohexanone (dimer) dehydrogenation were prepared by means of a two subsequent impregnation method.The effects of catalyst preparation parameters,such as K promoters,calcination,and reduction conditions,were investigated.The results showed that the addition of K2SO4 to Pt/y-Al2O3 catalyst notably promoted the selectivity of OPP,and its optimum content was found to be 6% in mass fraction.The higher activity was obtained when Pt/y-Al2O3 catalyst was calcined in nitrogen atmosphere at 400-500℃ and then reduced at the same temperature for 3 h in hydrogen atmosphere.The conversion of the dimer and the selectivity of OPP were always above 99% and 90%,respectively,over 0.5%Pt-6% K2SO4/γ-Al2O3 catalyst during the pilot scale test of 8000 h.     

X-ray absorption spectroscopy of Mn/Co/TiO2 Fischer-Tropsch catalysts: relationships between preparation method, molecular structure, and catalyst performance

The effects of the addition of manganese to a series of TiO(2)-supported cobalt Fischer-Tropsch (FT) catalysts prepared by different methods were studied by a combination of X-ray diffraction (XRD), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and in situ X-ray absorption fine structure (XAFS) spectroscopy at the Co and Mn K-edges. After calcination, the catalysts were generally composed of large Co(3)O(4) clusters in the range 15-35 nm and a MnO(2)-type phase, which existed either dispersed on the TiO(2) surface or covering the Co(3)O(4) particles. Manganese was also found to coexist with the Co(3)O(4) in the form of Co(3-x)Mn(x)O(4) solutions, as revealed by XRD and XAFS. Characterization of the catalysts after H(2) reduction at 350 degrees C by XAFS and TEM showed mostly the formation of very small Co(0) particles (around 2-6 nm), indicating that the cobalt phase tends to redisperse during the reduction process from Co(3)O(4) to Co(0). The presence of manganese was found to hamper the cobalt reducibility, with this effect being more severe when Co(3-x)Mn(x)O(4) solutions were initially present in the catalyst precursors. Moreover, the presence of manganese generally led to the formation of larger cobalt agglomerates ( approximately 8-15 nm) upon reduction, probably as a consequence of the decrease in cobalt reducibility. The XAFS results revealed that all reduced catalysts contained manganese entirely in a Mn(2+) state, and two well-distinguished compounds could be identified: (1) a highly dispersed Ti(2)MnO(4)-type phase located at the TiO(2) surface and (2) a less dispersed MnO phase being in the proximity of the cobalt particles. Furthermore, the MnO was also found to exist partially mixed with a CoO phase in the form of rock-salt Mn(1-x)Co(x)O-type solid solutions. The existence of the later solutions was further confirmed by scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) for a Mn-rich sample. Finally, the cobalt active site composition in the catalysts after reduction at 300 and 350 degrees C was linked to the catalytic performances obtained under reaction conditions of 220 degrees C, 1 bar, and H(2)/CO = 2. The catalysts with larger Co(0) particles ( approximately >5 nm) and lower Co reduction extents displayed a higher intrinsic hydrogenation activity and a longer catalyst lifetime. Interestingly, the MnO and Mn(1-x)Co(x)O species effectively promoted these larger Co(0) particles by increasing the C(5+) selectivity and decreasing the CH(4) production, while they did not significantly influence the selectivity of the catalysts containing very small Co(0) particles.