超细粒子催化剂用于CO加氢反应的研究

超细粒子催化剂以其良好的性能应用在CO加氢反应中,与沉淀法制得的催化剂相比,超细粒子催化剂活性高、产品选择性好、反应寿命长。本文还研究了加入不同助剂、由不同方法制备的和无定型合金超细粒子催化剂的F—T反应特性。     

超细粒子的合成技术

本文介绍了近年来超细粒子的主要制备方法，着重综述了微乳技术、超临界流体技术在超细粒子制备中的应用，并指出了其在研究和应用方面的进展。     

Sol-Gel法制备氧化铝负载铜基超细粒子影响因素的研究

通过对Sol-Gel法制备氧化铝负载铜基超细粒子的研究，表明PEG分散剂对粒度分布有重要影响；采用XRD对制得的催化剂表面组成进行了研究，指出了发生固相反应生成活性较低的CuAl2O4的影响因素。     

高分散负载型超细粒子催化剂的制备及应用

本文综述了高分散负载型超细粒子催化剂的制备及其在催化中应用的现状，展望了该类催化剂的应用前景。     

铜酞菁同质多晶现象的研究及其超细粒子的制备

采用路易斯酸配位法溶解了铜酞菁，并对路易斯酸溶解铜酞菁的机理进行了简单讨论，同时研究了溶解过程中不同溶剂对铜酞菁晶型的影响．最后，用路易斯酸溶解配位法和微射流纳米分散技术相结合的方法成功制备了铜酞菁超细粒子，并用激光粒度仪、原子力显微镜、紫外可见分光光度计对超细粒子的粒径和吸收光谱进行了表征．     

无载体Fe／Zn超细粒子催化剂的磁学性质

根据铁的磁性特点，借助磁性测试方法，研究了ＦＴ合成Ｆｅ／Ｚｎ超细粒子催化剂的磁学性质，并考察了样品还原后磁学性质的变化，利用程序升温热磁还原法（ＴＰＲＭ）对样品在程序升温还原过程中磁性的变化进行了跟踪，发现锌对铁的还原行为有显著影响，锌对铁的还原有抑制作用，并能够稳定二价铁，使其不易被进一步还原到零价态，针对样品的超细粒子的特点，观察了其超顺磁现象。     

硅胶负载型烯烃聚合催化剂的研究Ⅳ化学活化对催化剂形态的影响

ＳＥＭ观察发现了催化剂制备过程中颗粒的破碎和聚结现象，破碎随化学活化时三乙基铝量的增加而加剧，同时还发现了细粒子和碎片在粒径较大催化剂颗粒表面的聚结现象，发生聚结的细粒子或碎片的粒径一般在２０μｍ以下，破碎和聚结都破坏了催化剂的宏观形态，较多的三乙基铝量也改变了催化剂颗粒表面的微观形态，局部表面形成了絮团状物质     

杀菌防霉涂料

含二氧化钛光解催化剂的杀菌水溶性涂料及其制备 题述涂料含分散在水溶液[含水溶性（糖）醇类]中的二氧化钛和／或氢氧化钛超细粒子。例如，一种水性涂料含10％二氧化钛和／或氢氧化钛水溶液[由5mL四氯化钛在由50％（体积分数，下同）异丙醇和50％水构成的995mL溶液中反应制备]，具有良好的杀菌性和清洁性。     

TiO_2超细粒子的微乳法制备、表征及性能研究

采用表面活性剂OP-7、正庚烷、水和异戊醇形成的微乳体系制备TiO2超细粒子,并考察水和异戊醇含量对TiO2超细粒子平均粒径的影响。所得产物易于分离,溶剂可回收,产率达80%。结果表明,500℃灼烧2h所制备的TiO2超细粒子为锐钛型。采用FTIR、XRD、BET、DSC、TEM对TiO2超细粒子进行表征,由FTIR分析可知,表面无残留有机物;由DSC分析可得晶型转变温度为437 3℃;根据XRD分析计算的平均粒径为9 7nm,颗粒分散度较高;采用BET法测定比表面积为85 8m2/g。以苯酚的光催化氧化作为目标反应来评价TiO2超细粒子的光催化活性。苯酚光催化降解反应2 5h,降解率可达85%。     

固体超强酸催化剂改性研究进展

负载型固体超强酸是近年来发展的一种新型催化材料 ,对许多化学反应有较好的催化活性、选择性及重复使用性能 ,并可催化许多均相反应难以进行的各种化学反应。综述了国内外此类催化剂改性研究的最新进展 ,包括载体、促进剂、制备条件、酸中心结构的研究、利用纳米技术制备固体超强酸催化剂。讨论了固体超强酸催化剂理论及催化剂现代表征方法 ,催化剂酸中心形成、失活机理 ,固体超强酸催化剂的应用。最后指出了今后固体超强酸催化剂的发展方向     

超细镍粉的制备进展

超细镍粉是良好的电、磁热敏材料,在催化剂、磁性材料、烧结活化剂、导电浆料、电池材料、硬质合金粘结剂等方面具有广阔的应用前景,已成为国内外新颖功能材料开发的热点之一。文章简介了超细镍粉的物理、化学特性、应用领域及发展前景,并介绍了超细镍粉的几类较成熟的制备方法如固相法、液相法、气相法和电化学法及其研究进展,提出了制备纳米镍粉的一种新思路。引用文献32篇。     

高频氢等离子体增强还原制备超细铜粉

利用高频感应热氢等离子体强化还原制备超细铜粉,考察了加料速率、还原氢气流量、氢气分布位置、反应区空间、冷却温度等因素对铜粉颗粒性能的影响,对制备的铜粉颗粒进行氧含量、XRD晶体结构、松装密度、粒度分布和比表面积的表征。结果表明,优化的工艺条件为反应区内径100 mm,加料速率4 g/min,淬火气氩气气量500 L/h,氢气气量500 L/h并通入少量载气,由氢等离子电离产生的氢自由基可强化反应实现瞬时还原,不仅可控制铜粉形貌,还能有效控制铜粉颗粒大小;利用该方法制备出粒径分布100?200 nm、分散性好的超细球形铜粉颗粒。该方法操作简便、产品纯度高、气氛可控、对环境污染小。     

Synthesis of Higher Alcohols from Syngas over Ultrafine Mo—Co—K Catalysts

Ultrafine Mo–Co–K catalysts were prepared and tested for higher alcohol synthesis. The catalysts exhibited high catalytic activity. The effect of the mole ratio of cobalt and molybdenum in the catalysts upon the catalytic performance of higher alcohol synthesis was investigated. Among the ultrafine Mo–Co–K catalysts, the best one corresponded to the Co/Mo mole ratio of 1:7. The XPS spectra revealed that molybdenum was present in two species: Mo⁶⁺ and Mo⁴⁺ on the surface of reduced catalysts, and the Mo⁴⁺ species content depended strongly on the Co/Mo mole ratio. The selectivity towards higher alcohols was found to be related to the Mo⁴⁺ species content. A linear relation between the selectivity and Mo⁴⁺ species content led to the conclusion that the Mo⁴⁺ species was the main active species for higher alcohol synthesis over the ultrafine Mo–Co–K catalysts.     

CO2 Hydrogenation to Methanol Over Cu/ZnO/Al2O3 Catalysts Prepared by a Novel Gel-Network-Coprecipitation Method

A novel gel-network-coprecipitation process has been developed to prepare ultrafine Cu/ZnO/Al₂O₃ catalysts for methanol synthesis from CO₂ hydrogenation. It is demonstrated that the gel-network-coprecipitation method can allow the preparation of the ultrafine Cu/ZnO/Al₂O₃ catalysts by homogeneous coprecipitation of the metal nitrate salts in the gel network formed by gelatin solution, which makes the metallic copper in the reduced catalyst exist in much smaller crystallite size and exhibit a much higher metallic copper-specific surface area. The effect of the gel concentration of gelatin on the structure, morphology and catalytic properties of the Cu/ZnO/Al₂O₃ catalysts for methanol synthesis from hydrogenation of carbon dioxide was investigated. The Cu/ZnO/Al₂O₃ catalysts prepared by the gel-network-coprecipitation method exhibit a high catalytic activity and selectivity in CO₂ hydrogenation to methanol.     

Fischer-Tropsch synthesis on Fe-Mn ultrafine catalysts

The Fischer-Tropsch (FT) synthesis on Fe-Mn ultrafine catalysts prepared by a special degradation method of Fe-Mn complexes is presented. The effects of preparation method and Mn content on the FT performance are examined and the active phases and the role of Mn are elucidated.     

Modification of hierarchically porous SiC ultrafine fibers with tunable nitrogen-containing surface

Silicon carbide (SiC) has been regarded as a good catalyst support owning to its excellent properties. However, the weak interaction between SiC and noble metal nanoparticles (NPs) hindered the high dispersion of active NPs, resulting in low activity and poor durability. To create charged sites favorable for catalysts deposition, we applied an effective strategy to modify hierarchically porous SiC ultrafine fibers with tunable nitrogen-containing composition on the surface. The obtained N–C/SiC fibers can inherit the enhanced affinity of N–C with noble metal NPs as well as the intrinsic stability of SiC and the hierarchically porous structure. Thus it would be very promising as catalysts support for Fischer–Tropsch reaction, electrocatalytic reaction, etc, especially in harsh environment.     

改进共沉淀法制Cu基甲醇催化剂

采用传统共沉淀法和加表面活性剂改进共沉淀法制备了两种超细 Cu/ Zn O/ Al2 O3 催化剂 ,并应用 XRD,TEM对催化剂的结构和形貌进行了表征 ,同时用流动固定床微型反应器在3.0 MPa和体积空速 760 0 h-1下考察了其催化合成气合成甲醇的活性 .结果表明 ,改进共沉淀法制备的超细 Cu/ Zn O/ Al2 O3 催化剂具有比传统共沉淀法制备的催化剂更细的粒径和更高的催化活性 .同时从理论上对表面活性剂的作用机制进行了讨论 .     

Glucose hydrogenation on Co–B amorphous alloy catalysts and the promoting effect of metal additives

Two kinds of ultrafine Co–B amorphous alloy catalysts, denoted as P‐1 Co–B and P‐2W Co–B, were prepared by chemical reduction with borohydride in aqueous or 50% (v/v) ethanol/water solution, respectively. In comparison with the corresponding Co‐based crystalline catalysts and Ni‐based catalysts, these catalysts exhibited higher activity during the liquid phase glucose hydrogenation, possibly due to the unique amorphous characteristics and the lower d‐band electron density, which was favorable for hydrogen dissociative chemisorption. Addition of Cr‐, Mo‐ or W‐promoters could further increase the conversion of Co–B amorphous catalyst, which was mainly attributed to the dispersion effect of promoters and the adsorption and polarization of carbonyl groups by these promoters. The different effects of W‐ from Cr‐ and Mo‐promoters on the conversion were observed and are discussed. © 2001 Society of Chemical Industry     

溶胶-凝胶法负载型催化剂上糠醛加氢制备2-甲基呋喃

采用溶胶-凝胶法制备负载型Cu-Cr/SiO2催化剂,进行糠醛气相加氢合成2-甲基呋喃。在无梯度反应器中考察了Cu/Cr摩尔比、温度、氢醛摩尔比对催化加氢性能的影响。并通过X射线衍射探讨了催化剂的活性中心成分。