利用生物质气化合成气在FeCuZnAlK催化剂上高效制备清洁生物燃料

研究了生物质气化合成气在Fe_1.5Cu₁Zn₁Al₁K_0.117催化剂上高效转化为清洁生物燃料的合成过程. 利用生物质气化合成气合成的生物燃料最大产率为1.59 kg/(kgcatal·h), 其中醇占0.57 kg/(kgcatal·h), 液体烃占1.02 kg/(kgcatal·h). 在生物燃料中, 醇类产物主要为C2⁺醇(主要为C2-C6高碳醇), 其含量占总醇的7     

生物质气经由二甲醚两步法制备低碳烯烃

制备出NiSAPO-34及NiSAPO-34/HZSM-5催化剂,考察了其对二甲醚催化转化制备低碳烯烃的性能．利用Cu/Zn/Al/HZSM-5和筛选出的2%NiSAPO-34/HZSM-5催化剂进行生物质气经由二甲醚两步法制备低碳烯烃的实验, 结果表明在SAPO-34上添加2%的Ni不改变其结构, 但降低了酸中心数量, 并生成了较强的酸中心． 添加少量具有稳定酸中心的HZSM-5, 该催化剂的活性提高到3 h以上, 反应进行2 h获得了最高的低碳烯烃选择性为90.8%． 当把该催化剂应用到两步催化转化过程的第二个反应器中, 其高催化活性可达5 h以上． 当以低氢碳比生物质气(H₂/CO/CO₂/N₂/CH₄=41.5/26.9/14.2/14.6/2.89)作为原料时,经两步转化,低碳烯烃的收率达到84.6 g/m³_syngas．     

表面活性剂修饰的CuCoMn催化剂催化合成低碳醇

分别采用阳离子(十六烷基三甲基溴化铵,CTAB)、阴离子(十二烷基硫酸钠,SDS)、非离子(三嵌段共聚物,P123)三种不同类型的表面活性剂对CuCoMn基催化剂进行改性,利用N₂吸脱附、XRD、XPS、IR手段表征了催化剂的微观结构．在生物质基合成气合成高醇中的应用研究结果表明,SDS修饰的CuCoMn催化剂表现出较高的CO转化率(29.7%),而CTAB修饰的CuCoMn催化剂具有优良的高醇选择性(41.2%)．同时,三种表面活性剂修饰的催化剂均不同程度地提高了高醇产率及其在醇产     

GREAT MAGNETIC ENTROPY CHANGE IN La(Fe, M)13 (M=Si, Al) WITH Co DOPING

Very large magnetic entropy change Δ S_M, which originates from a fully reversible second-order transition at Curie temperature T_C, has been discovered in compounds La(Fe, Si)₁₃, La(Fe, Al)₁₃ and those with Co doping. The maximum change ΔS_M\approx19 J·kg^-1·K^-1, achieved in LaFe_11.4Si_1.6 at 209K upon a 5T magnetic field change, exceeds that of Gd by more than a factor of 2. The T_C of the Co-doped compounds shifts to higher temperatures. ΔS_M still has a considerable large magnitude near room temperature. The phenomena of very large ΔS_M, convenience of adjustment of T_C, and also thesuperiority of low cost, strongly suggest that the compounds La(Fe, M)₁₃ (M=Si, Al) with Co doping are suitable candidates for magnetic refrigerants at high temperatures.     

钴改性Fe3O4-MnO2催化转化生物质合成气制备液体燃料

本文制备了用于费托合成反应的钴改性Fe₃O₄-MnO₂双功能催化剂,并探究了钴负载量对Fe-Co协同效应的影响以及Fe₁Co_xMn₁催化剂的费托合成反应性能. 实验发现,在Fe₃O₄-Mn催化剂中加入Co可促进铁氧化物的还原、增加反应过程中铁位点的活性. 此外,Co的加入可增强Fe-Co金属间的电子转移,加强两者的协同作用,提高催化性能. Co负载较高的Fe₁Co_xMn₁催化剂可进一步促进加氢反应能力,使产品分布向短链烃方向转移. 在280 ^°C、2.0 MPa和3000 h^-1的最佳工况条件下,Fe₁Co₁Mn₁催化剂的液体燃料收率最高.     

纤维素和甲醇共催化热解制备对二甲苯

本文对纤维素和甲醇在不同金属氧化物改性的ZSM5催化剂作用下共催化快速热解实现一步制备可再生对二甲苯的过程进行了研究. 结果表明,镧改性的ZSM5催化剂是生产生物基对二甲苯的有效催化剂. 对二甲苯的选择性和产率主要由催化剂酸性、反应温度和甲醇含量决定. 在20%La₂O₃-ZSM5(80)催化剂作用下,纤维素与33wt%甲醇共催化快速热解获得对二甲苯的最高收率和对二甲苯/二甲苯的最高比率分别为14.5 C-mol%和86.8%. 本文详细研究了催化热解过程中催化剂的失活,基于产物的分析和催化剂的表征提出了由纤维素制备对二甲苯的可能反应途径.     

三元硅化物CaAlSi的结构和超导电性

应用线性响应的线性糕模轨道方法计算AlB₂型结构的新超导体CaAlSi的电子能带、声子谱及电子-声子耦合常数，并讨论了它们的超导电性.通过比较两种结构模型的计算结果可以看出：若CaAlSi中Al，Si原子沿c轴方向以—Al—Al—Al—(或—Si—Si—Si—) 排列，低频B_1g模式的声子频率沿A-L方向出现虚频, 使得这种结构处于不稳定状态，电子-声子耦合表现异常增大；若Al，Si原子沿c轴     

基于约束非平衡溶剂化理论的对硝基苯胺π-π*光谱移动 (cited: 1)

采用共沉淀法制备不同组分类水滑石前驱体Co-M-Al和Co-M-Ce-Al (M=Zn, Ni, Cu)复合氧化物催化剂催化分解N₂O. 结果表明,Co-M-Al系列氧化物催化剂的催化活性Co-Ni-Al系列>Co-Zn-Al系列>Co-Cu-Al系列;CeO₂添加使得催化剂催化活性进一步提高,N₂O分解温度T₅₀和T₉₀均下降80 oC;继续负载碱金属K也使氧化物催化剂催化活性提高,N₂O分解温度T₅₀和T₉₀下降约50 oC.     

Superacid Catalyst SO42-/ZrO2-La2O3 Prepared by Ultrasonic Co-precipitation and Low Temperature Aging

低温陈化超声波共沉淀法制得SO₄^2-/ZrO^2-La₂O₃前驱体, 经H₂SO₄处理, 在不同温度下焙烧得到纳米晶催化剂SO₄^2-/ZrO^2-La₂O₃;用Hammett指示剂法测定其酸性. 用XRD、BET、TEM、IR和XPS对样品进行表征,其催化活性用醋酸和甘油的酯化反应进行了评价. 结果表明经超声波搅拌和低温(-15 ºC)陈化,650 ºC焙烧4 h得到的固体超强酸表现出较高催化活性.     

在太阳光照射和不外加酸下TiO2双功能催化剂光催化还原Cr(VI)离子

利用硫酸氧钛铵的热分解控制制备了氮和硫共同掺杂的TiO₂双功能光催化剂. TiO₂双功能光催化剂同时具备光催化性能和较强的Br?nsted酸性,因此能够在太阳光照射和不外加酸下有效光催化还原Cr(VI)离子. 其光催化还原Cr(VI)离子的活性要优于通过外加硫酸调节到等同pH值和太阳光照射下P25光催化剂光催化还原Cr(VI)离子的活性.     

Synthesis of Pt modified ZSM-5 and beta zeolite catalysts: influence of ultrasonic irradiation and preparation methods on physico-chemical and catalytic properties in pentane isomerization

Influence of preparation methods and ultrasound irradiation on physico-chemical and catalytic properties was investigated by synthesizing Pt-ZSM-5 and Pt-Beta catalysts by in-situ and impregnation methods and applying ultrasound irradiation to synthesis gel mixture of ZSM-5 and Beta zeolites. It was concluded from the X-ray powder diffraction patterns of Pt-ZSM-5 and Pt-Beta zeolite catalysts that introduction of Pt by in-situ method and ultrasound irradiation did not influence the structures of ZSM-5 and Beta zeolites. Morphology of ZSM-5 and Beta zeolites were investigated by scanning electron microscopy. SEM micrographs showed that the Pt-ZSM-5-IS-US catalyst synthesized by in-situ method with ultrasound irradiation resulted in smaller crystals of ZSM-5 than Pt-ZSM-5-IS catalyst prepared without ultrasound irradiation. Furthermore SEM micrographs of Pt-Beta-11-IS-US zeolite synthesized using ultrasound irradiation showed much smaller crystals than Pt-Beta-11-IM indicating that ultrasound irradiation had a significant effect on the morphology of Beta zeolite. Conversion of n-pentane and selectivity to iso-pentane over the Pt-ZSM-5-IS-US zeolite catalysts prepared by ultrasound irradiation during in-situ introduction of platinum was higher than the catalysts prepared without the ultrasound irradiation. Furthermore ultrasound irradiated and in-situ synthesized Pt-Beta-11-IS-US catalyst also showed higher selectivity to iso-pentane than Pt-H-Beta-11-IM prepared by impregnation method.     

The Study of Zeolite ZSM-5 by Auger Electron Spectroscopy

The dependence of the surface Si/Al ratio in function of the volume Si/Al ratio was studied, for zeolite of type: A, X, clinoptilolite, mordenite and three samples of ZSM-5. Surface measurements were made by Auger electron spectroscopy (AES), and volume (bulk) measurements by atomic absorption spectrophotometry. It was found that the surface Si/Al ratio is identical with the volume Si/Al ratio. The dependence of the surface Si/Al ratio on the crystallization degree for zeolite ZSM-5 was also studied. We obtained some informations about the kinetics and mechanism of the crystallization process.     

镍改性ZSM-5催化剂及其SCR催化性能

采用液态离子交换法制备了不同负载量的镍改性ZSM-5分子筛催化剂,并考察了上述催化剂的微观结构和物理化学特性及其在NH3-SCR反应中的催化性能。结果表明:在负载量<10.9%时镍在分子筛中具有高度的分散性,而随着镍负载量的进一步增加,分子筛表面开始出现较大的NiO颗粒;镍元素只以+2价存在于分子筛催化剂中;在NH₃-SCR反应中,镍负载量低于14.9%时,增加镍负载量将提高催化剂的低温活性;当反应温度超过300℃时,高温催化中心开始起作用,但随镍负载量的增加,高温活性开始下降时的温度逐渐降低。     

Fe-ZSM-5杂原子分子筛的合成与表征

采用静态水热法分别以正丁胺、四丙基溴化铵为模板剂合成ZSM-5分子筛及Fe-ZSM-5杂原子分子筛；利用XRD与FT-IR对其结构进行表征；考察了Mo改性后分子筛催化剂上甲烷脱氢芳构化的反应性能。结果表明，Fe部分进入了分子筛的骨架，导致分子筛的结晶度及表面酸强度的下降，使Mo／Fe-ZSM-5催化剂的反应性能较Mo／HZSM-5显著下降。     

Electrical conductivity response and sensitivity of ZSM-5, Y,and mordenite zeolites towards ethanol vapor

This work is an attempt to search for highly selective sensing materials for ethanol vapor. The electrical conductivity response of ZSM-5, Y, and mordenite zeolites towards ethanol vapor have been investigated for the effects of the framework, the charge balancing cation type, and the Si/Al ratio. All zeolites were characterized using XRD, FT-IR, SEM, TGA, BET, and NH₃-TPD techniques. For the effect of the zeolite framework type, H⁺Y has a higher electrical conductivity sensitivity value than that of H⁺MOR because of a greater pore volume and available surface area. For the effect of the charge balancing cation, all NH₄ ⁺ZSM-5 zeolites (Si/Al = 23, 50, 80, 280) show negative responses, whereas the H⁺Y zeolites (Si/Al = 30, 60, 80) and the H⁺MOR zeolites (Si/Al = 30, 200) show positive responses. These differing behaviors can be traced to the electrostatic field at the cation sites in zeolite micropores, and their hydrophilic–hydrophobic character, which affect the adsorption properties of the zeolites. For the effect of Si/Al ratio, the electrical conductivity sensitivity towards the ethanol decreases with increasing Si/Al ratio or decreasing Al content, and there is a lesser degree of interaction between ethanol molecules and the active sites of the zeolites due to its higher hydrophobicity and the lower amount of cations. However, the H⁺Y (Si/Al = 5.1) and the H⁺MOR (Si/Al = 19) zeolites have lower conductivity sensitivity than those of H⁺Y (Si/Al = 30) and H⁺MOR (Si/Al = 30), respectively. The interactions between the C₂H₅OH molecules and the zeolites with respect to the electrical conductivity sensitivity were investigated and verified through infrared spectroscopy.     

Physicochemical characteristics of ZSM-5/SAPO-34 composite catalyst for MTO reaction

SAPO-34 and ZSM-5 are the most well-known catalyst for MTO reaction. A combination of ZSM-5 and SAPO-34 might give rise to optimal catalyst to meet a change of market demand for ethylene, propylene and butadiene. In this study, we have developed ZSM-5/SAPO-34 composite catalysts to control the composition of light olefins in MTO reaction. ZSM-5/SAPO-34 composite catalysts showed very different physicochemical and catalytic properties with respect to ZSM-5 and SAPO-34 synthetic procedure. The physicochemical properties of the composite catalysts have been compared by XRD, SEM, N₂ isotherm, FT-IR and NH₃-TPD. Their catalytic performances were also evaluated for MTO reaction. The series composite catalyst synthesized by successive crystallization of SAPO-34 synthetic gel after ZSM-5 crystallization exhibited relatively high catalytic performance.     

The Study of Zeolite ZSM-5 by a Dielectric Spectroscopy Method

The dielectric absorption spectrum of zeolite ZSM-5, in the range of frequencies 100 c - 10 Mc, was studied. The influence of the crystallization degree and influence of the Si/Al ratio on the amplitude of the dielectric absorption were analysed. It was observed that _max depends on the Si/Al ratio in an exponential form. An excess of Et.OH in the mixture of crystallization influences favorably the kinetics of the process.     

Mn／ZSM-5催化剂及其SCR催化性能研究

采用液态离子交换法制备了不同含量的Mn／ZSM-5型分子筛催化剂,并考察了上述催化剂的物理化学特性及其在NH3-SCR反应中的催化性能。理化分析结果表明：所制备催化剂在Mn含量≤9．2％时具有高度的分散性,分子筛表面团聚的氧化锰颗粒粒径小于4nm;锰元素主要富集于分子筛的浅层及表面。催化性能研究结果表明：Mn含量达到1...     

Ultrasound-assisted rapid hydrothermal design of efficient nanostructured MFI-Type aluminosilicate catalyst for methanol to propylene reaction

The influence of ultrasound-assisted rapid hydrothermal synthesis of aluminosilicate ZSM-5 catalysts was examined in this work. A series of MFI-type nanostructured materials with sonochemical approach and conventional heating were synthesized and evaluated for conversion of methanol to propylene reaction. The prepared samples were tested by characterization analyses such as XRD, FESEM, BET-BJH, FTIR, TPD-NH₃ and TG/DTG. The obtained results confirmed that ultrasound treatment enhanced the nucleation process and crystal growth for ZSM-5 sample synthesized at moderate temperature of 250 °C. Therefore, it was found the formation of pure MFI zeolite with high crystallinity and improved textural, structural and acidic properties for ZSM-5(UH-250) sample compared with the other zeolites. This observation was attributed to the relationship between the perfect crystallization mechanism and catalytic properties, which led to producing an efficient MFI zeolite toward the optimal catalytic performance. In this manner, the methanol conversion and products selectivity of prepared materials were carried out in MTP reaction at 460 °C and atmospheric pressure. The ZSM-5(UH-250) zeolite with slower deactivation regime exhibited the constant level of methanol conversion (84%) and high propylene selectivity (78%) after 2100 min time on stream. Moreover, the synthesis pathway for MFI zeolite at moderate temperature and also deactivation mechanism of improved sample were proposed.     

Experimental and simulated propene isotherms on porous solids

The lack of treatment capacity of hydrocarbons by three-way catalysts during the “cold start” period creates an important environmental problem. During this period, the temperature of the three-way catalyst is too low for effective operation and cannot convert the hydrocarbons in the exhaust. 50-80% of the total hydrocarbon emissions are produced in this phase that accomplishes the first 60-120 s of the engine operation. In this study, the technology chosen to treat these emissions is the use of HC-traps, and molecular simulations are tested as a tool to reproduce the experimental adsorption behaviour of porous solids. Therefore, experimental and simulated adsorption isotherms of propene (model hydrocarbon) have been obtained for four different crystalline materials with distinctive framework structures (3D and 1D) and a variety of Si/Al ratios and cations (three zeolites: ZSM-5, BETA and Mordenite; and a silicoaluminophosphate molecular sieve: SAPO-5).