Selective Oxidation of CO in Excess H2 over Ru/Al2O3 Catalysts Modified with Metal Oxide

The Ru/Al_2O_3 catalysts modified with metal oxide(K_2O and La_2O_3)were prepared via incipient wetness impregnation method from RuCl_3·nH_2O mixed with nitrate loading on Al_2O3 support. The activity of catalysts was evaluated under simulative conditions for the preferential oxidation of CO (CO-PROX)from the hydrogen-rich gas streams produced by reforming gas,and the performances of catalysts were investigated by XRD and TPR.The results showed that the activity temperature of the modified catalysts Ru-K_2O/Al_2O3 and Ru-La_2O_3/Al_2O_3 were lowered approximately 30℃compared with pure Ru/Al_2O_3,and the activity temperature range was widened.The conversion of CO on Ru-K_2O/Al_2O_3 and Ru-La_2O_3/Al_2O_3 was above 99% at 140-160℃,suitable to remove CO in a hydrogen-rich gas and the selectivity of Ru-La_2O_3/Al_2O_3 was higher than that of Ru-K_2O/Al_2O_3 in the active temperature range. Slight methanation reaction was detected at 220℃and above.     

矿物质氧化物对燃煤烟气中砷/铅的吸附特性研究

选取典型的矿物质氧化物为吸附剂，在两段式固定床反应器中研究了模拟烟气气氛下吸附剂吸附As₂O₃、PbO的特性，吸附反应的原子态密度、吸附位、吸附能等通过密度泛函理论（DFT）计算获得。结果表明，CaO的砷吸附容量最大，900 ℃吸附砷容量为5.25 mg/g；其次是Fe₂O₃、MgO、Al₂O₃，吸附的砷以As³⁺和As⁵⁺的砷酸盐形式存在，高岭土和飞灰具有较大的PbO吸附容量，最大吸附容量分别为6.69和2.75 mg/g；其次是SiO₂和Al₂O₃，并且50%SiO₂/50%Al₂O₃ 混合吸附剂的铅吸附容量高于单一氧化物，吸附剂表面O原子是As₂O₃的吸附活性位点，吸附剂暴露的不饱和Si和Al原子是PbO的吸附活性位点，此外温度、烟气气氛对吸附容量和吸附产物有显著影响。     

Ni/MgO/Al2O3催化剂上以1-甲基萘为模型化合物高温焦炉煤气焦油的催化转化

采用共浸渍薄水铝石(AlOOH)方法制备了一系列Ni/MgO/Al₂O₃催化剂, 并采用N₂气吸附及Ｘ射线衍射等手段进行了表征. 选择1-甲基萘作为焦油模型化合物, 研究了该催化剂催化转化具有较低水蒸气/碳摩尔比(n_H2O/n_C) 的高温焦炉煤气(COG)中焦油催化反应性能. 考察了催化剂中MgO含量及反应条件等对催化剂性能的影响. 实验结果表明, 在775 ℃和n_H2O/n_C=0.7条件下, MgO改性的Ni/MgO/Al₂O₃催化剂对1-甲基萘催化转化为小分子气体反应具有较好的催化活性和稳定性; 热重分析表明, MgO的加入能显著提高催化剂的抗积炭能力. 在Ni/MgO/Al₂O₃催化剂上, 反应气中高浓度H₂S气体(0.25%, 体积分数)能够促进焦油催化转化为小分子气体, 这可能是由于H₂S在Ni表面的可逆吸附形成更适合于重整反应的活性位, 同时抑制了烷烃裂解吸附形成的碳在金属中的溶解、扩散并最终形成积炭过程.     

Aluminum-type superparamagnetic adsorbents: Synthesis and application on fluoride removal

Two effective types of superparamagnetic nano-scale adsorbents of bayerite/SiO₂/Fe₃O₄ have been synthesized via three sequential steps: chemical precipitation of Fe₃O₄, coating of SiO₂ on Fe₃O₄ using acidifying method, and further coating of bayerite (Al(OH)₃) on SiO₂/Fe₃O₄ adopting sol–gel (MASG) or homogeneous precipitation (MAHP) methods. The characteristics of MASG and MAHP were identified using the transmission electron microscopy (TEM) micrograph, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray powder diffractometer (XRD), and superconducing quantum interference device (SQUID). Removal of fluoride from aqueous solution was examined to evaluate the adsorptive capacity of MASG, MAHP, and commercial activated alumina (CA), and the effects of enclosure of Fe₃O₄ with SiO₂ for SiO₂/Fe₃O₄, MASG, and MAHP particles. Among the adsorbents tested under the same experimental condition, MASG is the most effective adsorbent, of which the adsorption capacities are 38 g/kg (based on adsorbent mass of adsorption in terms of equilibrium constant q_L of Langmuir isotherm), and can compete with CA even at a high pH value. The innovative superparamagnetic adsorbents synthesized in this study possess physicochemical stability at pH range of 6–8 and great potential in the adsorption processes due to not only their high adsorption capacity but also the conveniently magnetic separation which can overcome the difficulty in solid–liquid separation for nano-particles in solutions.     

Synthesis of alumina nanotubes using carbon nanotubes as templates

Alumina nanotubes have been fabricated using carbon nanotubes (CNTs) as templates at 1473 K. The Al₂O₃ nanotubes are polycrystals. They are less than 100 nm in outer diameter and tens of nanometer in inner diameter, which is close to the outer diameters of the templates. Under certain conditions, AlN and Al₂O₃ nanowires can also be fabricated in this reaction system. Discussions on the growth mechanisms of these nanotubes and nanowires are presented.     

碳纳米管/FeS类Fenton催化剂的制备及催化性能

以浮动催化热分解法制备碳纳米管(CNTs), 采用氧化-还原-硫化的方法制备了CNTs/FeS催化剂, 采用X射线衍射(XRD)、 透射电子显微镜(TEM)和热重(TG)分析等技术对催化剂进行了结构表征. 将CNTs/FeS作为类Fenton催化剂用于水中环丙沙星的去除, 研究了降解过程中H₂O₂浓度、 CNTs/FeS催化剂的投加量、 环丙沙星浓度及pH等因素对催化降解性能的影响. 结果表明, CNTs/FeS类Fenton催化反应在H₂O₂浓度为20 mmol/L和CNTs/FeS催化剂的投加量为10 mg的条件下具有最优的降解效果, 其催化反应过程符合一级动力学方程, 且具有更加宽泛的pH适应范围(pH=3~8), 同时, CNTs/FeS类Fenton催化剂在使用寿命方面也具有一定的优势.     

新型磷酸硅铝分子筛SAPO-56的合成与表征

以N,N,N',N'-四甲基-1,6-己二胺(TMHD)为模板剂,采用水热法在Al₂O₃-P₂O₅-SiO₂体系中合成了SAPO-56分子筛.固定模板剂和水,得到Al-Si-P三元体系相图.当原料物质的量比为0.52)/n(M)<0.7(M=SiO²⁺Al₂O³⁺P₂O₅),0.152O₃)/n(M)<0.4及0.12O₅)/n(M)<0.3时,出现SAPO-56合成的纯相区.固定合成凝胶中硅、铝、磷和水的量,模板剂的用量改变对合成影响较大.n(TMHD)/n(P₂O₅)≥2时,产物是纯SAPO-56.用XRD,SEM,IR,DTA-TG和吸附等方法研究了产物的物化性能.结果表明,SAPO-56分子筛具有较好的热稳定性(骨架坍塌温度为1150℃)和较大的水吸附量(41%).SAPO-56分子筛催化剂对甲醇转化制烯烃反应表现出了良好的催化活性和较高的C₂和C₃烯烃选择性.     

Pd/Co3O4纳米颗粒负载于Al2O3纳米片高效催化甲烷燃烧

We report an efficient catalyst composed of ternary components prepared by inlaying Pd/Co₃O₄ nanoparticles in alkaline Al₂O₃ nanosheets for catalytic oxidation of methane. Pd/Co₃O₄ inlaid in alkaline Al₂O₃ exhibited a higher ability to break the C-H bond of methane than Pd/Co₃O₄ supported on SiO₂, ZrO₂, CeO₂, and acidic or neutral Al₂O₃. Our results show more oxygen vacancies and higher amounts of surface adsorbed oxygen on the surface of Pd/Co₃O₄/alkaline Al₂O₃ than on other catalysts, which is responsible for methane activation and conversion. Further, the Pd/Co₃O₄/alkaline Al₂O₃ catalyst can almost restore to its initial value in the absence of water when 5% (volume fraction) vapor water was cut off, although a decrease in activity occurred when water vapor was introduced to the reaction system. Even under a condition similar to the exhaust of a lean-burn natural gas engine, the catalytic performance of the Pd/Co₃O₄/alkaline Al₂O₃ catalyst is excellent, that is, methane could be completely converted when the sample temperature in the reaction atmosphere was ramped to 400℃.     

Co/Fe/Al2O3/cordierite催化C3H6选择性还原NO的实验研究

采用溶胶凝胶法和浸渍法制备了负载于蜂窝陶瓷上的Co/Fe/Al₂O₃/cordierite催化剂,在陶瓷管流动反应器上对其催化C₃H₆选择性还原NO的性能进行了测试。结果表明,该催化剂表现出最优脱硝性能,在模拟烟气条件下,当反应温度为550 ℃时可实现97%的脱硝效率。Co的引入可显著增强Fe/Al₂O₃/cordierite催化剂抗SO₂和H₂O的能力。在模拟烟气中同时引入0.02% SO₂和3% H₂O后,1.5Co/Fe/Al₂O₃/cordierite的脱硝性能受影响甚微,当反应温度高于500 ℃时1.5Co/Fe/Al₂O₃/cordierite催化C₃H₆还原NO的效率均可达到90%以上;相比之下,未经Co修饰的催化剂Fe/Al₂O₃/cordierite脱硝性能受到了严重的抑制,在整个反应温度区间（200-700 ℃）内,其催化C₃H₆还原NO的效率最高不足50%。XRD和SEM表征结果表明,经过适量的Co修饰后的1.5Co/Fe/Al₂O₃/cordierite表面变得更疏松,且形成了以钴铁和钴铝双金属氧化物为主要成分的球状晶粒。H₂-TPR结果表明,相比于Fe/Al₂O₃/cordierite,1.5Co/Fe/Al₂O₃/cordierite有更好的低温还原性能。Py-FTIR结果表明,Co的引入可使催化剂表面的Lewis酸明显增加,且生成了Brønsted酸。N₂吸附-脱附表征结果表明,Co可增大催化剂的比表面积。     

CO分子在不同类型Al2O3表面的吸附构型和电子结构

采用基于赝势平面波基组的密度泛函理论方法对CO分子在α-Al₂O₃（0001）以及γ-Al₂O₃的（100）、（110C）、（110D）表面上的吸附构型和电子结构进行系统研究.计算结果表明,CO倾向于选取C端吸附在表层Al原子上,并主要通过其5σ轨道与表面发生作用,吸附后部分电子从CO转移到底物,导致各Al₂O₃表面功函均发生不同程度的下降,与气相相比,吸附后CO分子的C-O伸缩振动频率均发生蓝移.通过对比CO在各表面上的吸附情况,可以看出CO可作为检测Al₂O₂不同类型表面活性中心的有效探针分子.     

新晶态磷酸铝分子筛CFAP-6的合成与性质

磷酸铝分子筛是新的一类晶态无机材料.1982年美国联合碳化物公司首次公布了约廿种不同结构的磷酸铝分子筛的合成专利^[1],作者在研究P₂O₅-Al₂O₃-H₂O系统的水热合成中^[2],发现用Al₂(SO₄)₃溶液作为Al₂O₃源,固体(NH₄)₃PO₄·3H₂O作为P₂O₅源,加入适量的有机胺,也能合成分子筛相,新晶态分子筛CFAP-6就是用上述原料,在二正丁胺-(NH₄)₂O-P₂O₅-Al₂O₃-H₂O系统中水热合成的。     

新型大孔结构重油加氢催化剂的制备、表征与评价

将聚苯乙烯（PS）颗粒模板加入到铝溶胶中,经干燥、煅烧除去PS模板制备了大孔氧化铝载体;采用低温N₂吸附 脱附和SEM对合成Al₂O₃的孔结构进行了表征;将Co-Mo活性组分担载在大孔氧化铝载体上制得重油加氢催化剂,并以大港焦化蜡油为原料在固定床高压微反装置上对合成的催化剂进行活性评价。实验表明,加入PS模板后,Al2O3的比表面积增加了41.5m²/g,孔体积增加了0.35cm³/g;加氢脱硫活性提高了12%,脱氮活性提高了22%。     

Adsorption of bacterial surface polysaccharides on mineral oxides is mediated by hydrogen bonds

Adhesion of bacterial cells to solid surfaces is often largely affected by bacterial surface polymers. In this study, we investigated the adsorption of three different O-antigens isolated from bacterial lipopolysaccharides on TiO₂, Al₂O₃, and SiO₂. The O-antigens of Escherichia coli 08 DSM 46243 and Citrobacter freundii PCM 1487 had high affinity for TiO₂ and low affinity for Al₂O₃, whereas the O-antigens of Stenotrophomonas maltophilia 70401 had low affinities for both surfaces. Adsorption on SiO₂ was low for all polysaccharides. The dependence of the adsorption on the molecular mass of polysaccharides was investigated with dextrans of various chain lengths. The affinity increased with the molecular mass. The affinity of the dextrans was reduced compared with the O-antigen of E. coli, which had similar chemical composition and molecular mass. The adsorption of the E. coli and C. freundii O-antigens on Al₂O₃ and TiO₂ was irreversible, whereas for the S. maltophilia O-antigen it was partially reversible. The reversibility of dextran adsorption decreased with increasing molecular mass.

Infrared spectroscopy showed that all bacterial O-antigens and the dextrans formed hydrogen bonds with surface hydroxyl groups or interacted with surface-bound water of TiO₂, Al₂O₃, and SiO₂. A concentration-dependent mechanism of adsorption was observed with TiO₂. At low polysaccharide concentrations, the surface water molecules ware replaced by the polysaccharides, and at increased concentration the surface hydroxyl groups were involved in the formation of hydrogen bonds. At higher surface coverages, the adsorbed polysaccharides formed loops between the few adsorbed units.     

负载型氨基功能化离子液体吸附CO2性能差异研究

以Al₂O₃、SiO₂和活性炭为载体,采用浸渍法制备了负载型离子液体（[NH₂p-mim]X:X= Br-,PF₆-,BF₄-,NTf₂-）CO₂吸附剂,利用红外光谱（FT-IR）、元素分析(EA)、热重差热分析（TG-DTA）等技术对负载型离子     

程序升温脱附法对低变反应体系的吸-脱附研究

本文采用程序升温脱附法(TPD)研究了低变反应各组分CO、H₂O、CO₂和H₂在Cu/ZnO/A1₂O₃型低变催化剂上的吸-脱附行为,并对与Cu/ZnO/A1₂O₃具有可此相对组成的六种样品进行了类似的讨论,通过对所得TPD谱图的定性分析发现:构成Cu/ZnO/A1₂O₃型低变催化剂的各个组元对低变反应各组分的吸-脱附作用互不相同,且不同的组元具有各自的吸-脱附特征。     

不同吸附剂上动态吸附-脱附挥发性有机气体性能研究

采用气相色谱法和热重分析(TG)研究了活性炭以及5A、NaY、13X、ZSM-5(Si0_2/Al_2O_3=27、300)、Hβ和MCM-41分子筛对正己烷、甲苯和乙酸乙酯的动态吸附-脱附性能,系统考察了挥发性有机气体(VOCs)浓度与种类及体积空速对吸附容量的影响。结果表明,增加体积空速和VOCs浓度,一定程度上能够提升吸附容量;活性炭吸附剂对三种VOCs具有较高的单位质量吸附量,而13X与NaY对三种VOCs具有更大的单位体积吸附量。     

Ruthenium Catalyst Supported on New Type of Graphite-Doped Alumina for Ammonia Synthesis

In the study of Ru catalyst, various supports have been used, e. g. MgO, Al₂O₃, MgAl₂O₄, zeolite active carbon^[1-3]. The carbon covered alumina offers the advantages of the electron withdrawing capacity of carbon and the stability of alumina and at the same tame eliminates the disadvantages of the low strength of carbon and the acidity of alumina. In the present work., we describe the synthesis and reactivity of ruthenium supported on various Al₂O₃ for the production of ammonia from hydrogen and nitrogen.     

Green synthesis of methyl trifluoropyruvate catalyzed by solid acids

Solid acids – NiSO₄/Al₂O₃, Fe₂(SO₄)₃/Al₂O₃ and TiO₂/SO₄²⁻ – appeared to be effective catalysts for the acid catalyzed synthesis of methyl ester of trifluoropyruvic acid. They are active at 150–180 °C.     

不同载体Ni基催化剂生物质热解气甲烷化反应性能

采用浸渍法制备了Ni金属负载在不同载体(SiO2、ZrO2、CeO2、Al2O3和Al2O3-CeO2)表面形成的催化剂,研究了水蒸气和载体对生物质热解气甲烷化反应性能的影响。结果表明,随着水蒸气量的增加CO转化率逐渐增大,而甲烷选择性呈现先增加后降低的变化趋势,当nw ater/ngas比值为0.26时达到最大。载体Al2O3相比SiO2、ZrO2和CeO2具有更大的比表面积和Ni金属分散度,促进了生物质热解气甲烷化反应活性和选择性。相比于Ni-Al2O3催化剂,Al2O3-CeO2复合载体具有更多的镍金属负载量活性金属分散度,以及最好的低温甲烷化反应性能。在300℃的低温条件下,Ni-Al2O3-CeO2催化剂的CO转化率达到97%,CH4增长率达到110%。     

生物柴油合成反应中KNO3/Al2O3催化剂的活性物种与失活研究

制备了KNO₃/Al₂O₃负载型固体碱催化剂，通过XRD、DRIFT、低温氮吸附、ICP和碱度滴定等手段对催化剂表面性质进行了表征，研究了其对大豆油与甲醇酯交换制备生物柴油的催化性能，剖析了在反应过程中该催化剂的催化本质以及失活原因。结果表明，高温焙烧后Al₂O₃表面KNO₃完全分解，形成了大量偏铝酸钾分散在载体表面；在酯交换反应时Al₂O₃表面的偏铝酸盐等活性组分不断溶出并参与反应，这是该催化剂表现出高活性的主要原因。在反应过程中生成的产物生物柴油和甘油对催化剂的活性有很大影响，其中，生物柴油与活性物种发生的皂化反应是造成催化剂失活的主要原因。