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Solvent‐Free Syntheses of Hierarchically Porous Aluminophosphate‐Based Zeolites with AEL and AFI Structures
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Yinying Jin Xian Chen Qi Sun Na Sheng Dr. Yan Liu Chaoqun Bian Fang Chen Dr. Xiangju Meng Prof. Feng‐Shou Xiao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17616-17623
Development of sustainable routes for synthesizing aluminophosphate‐based zeolites are very important because of their wide applications. As a typical sustainable route, solvent‐free synthesis of zeolites not only decreases polluted wastes but also increases product yields. Systematic solvent‐free syntheses of hierarchically porous aluminophosphate‐based zeolites with AEL and AFI structures is presented. XRD patterns and SEM images show that these samples have high crystallinity. N2 sorption isotherm tests show that these samples are hierarchically porous, and their surface areas are comparable with those of corresponding zeolites from hydrothermal route. Chosen as an example, catalytic oxidation of ethylbenzene with O2 shows that cobalt substituted APO‐11 from the solvent‐free route (S‐CoAPO‐11) is more active than conventional CoAPO‐11 from hydrothermal route owing to the sample hierarchical porosity. 相似文献
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Gas Phase Selective Catalytic Oxidation of Toluene to Benzaldehyde on V2O5-Ag2O/η-Al2O3 Catalyst 总被引:1,自引:0,他引:1
TonglaiZhang LiqiuMao WeihuaLiu 《天然气化学杂志》2004,13(4):238-243
Gas phase selective catalytic oxidation of toluene to benzaldehyde was studied on V2O5-Ag2O/η-Al2O3 catalyst prepared by impregnation. The catalyst was characterized by XRD, XPS, TEM,and FT-IR. The catalytic results showed that toluene conversion and selectivity for benzaldehyde on catalyst sample No.4 (V/(V Ag)=0.68) was higher than other catalysts with different V/Ag ratios. This was attributed to the higher surface area, larger pore volume and pore diameter of the catalyst sample No.4 than the other catalysts. The XRD patterns recorded from the catalyst before and after the oxidation reaction revealed that the new phases were developed, and this suggested that silver had entered the vanadium lattice. XPS results showed that the vanadium on the surface of No.4 and No.5 sample was more than that in the bulk, thus forming a vanadium rich layer on the surface. It was noted that when the catalyst was doped by potassium promoter, the toluene conversion and selectivity for benzalde hydewere higher than those on the undoped catalyst. This was attributed to the disordered structure of V2O5 lattice of the K-doped catalyst and a better interfacial contact between the particles. 相似文献
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采用模拟实验方法,在氧化气氛工况和SCR(选择性催化还原法)工况下,对比研究新鲜的和运行40 000 h的SCR催化剂对零价汞(Hg0)的氧化效率,并结合N2吸/脱附、SEM-EDS、FT-IR、离子色谱法等手段对催化剂的组成及结构进行了表征。结果表明,在氧化气氛工况下(一定的HCl和O2浓度),40 000 h催化剂对零价汞的氧化效率比新鲜催化剂低5%~20%,但是,在SCR工况(氧化气氛下加入NH3和NO)下,氧化效率仅下降5%~10%。运行40 000 h催化剂出现表面颗粒的团聚现像,而且比表面积、活性物质V及V5+=O基团的含量均相对下降;然而,运行40 000 h催化剂的水溶性离子含量(特别是Na+、K+、NH4+、SO42-)要高于新鲜催化剂。这些因素都会影响催化剂表面活性位和内部孔道结构,从而影响到催化剂对于烟气中Hg0的氧化效率。 相似文献
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Gas phase selective catalytic oxidation of toluene to benzaldehyde was studied on V2O5-Ag2O/η-Al2O3 catalyst prepared by impregnation. The catalyst was characterized by XRD, XPS, TEM,and FT-IR. The catalytic results showed that toluene conversion and selectivity for benzaldehyde on catalyst sample No.4 (V/(V Ag)=0.68) was higher than other catalysts with different V/Ag ratios. This was attributed to the higher surface area, larger pore volume and pore diameter of the catalyst sample No.4 than the other catalysts. The XRD patterns recorded from the catalyst before and after the oxidation reaction revealed that the new phases were developed, and this suggested that silver had entered the vanadium lattice. XPS results showed that the vanadium on the surface of No.4 and No.5 sample was more than that in the bulk, thus forming a vanadium rich layer on the surface. It was noted that when the catalyst was doped by potassium promoter, the toluene conversion and selectivity for benzaldehyde were higher than those on the undoped catalyst. This was attributed to the disordered structure of V2O5 lattice of the K-doped catalyst and a better interfacial contact between the particles. 相似文献
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甲苯气相选择氧化制苯甲醛 Ⅳ.助剂锂、钾、铯对V_2O_5/TiO_2催化剂性能的影响 总被引:1,自引:0,他引:1
在V2O5/TiO2催化剂中分别添加Li、K、Cs等碱金属离子,利用BET、XRD、XPS、H2-TPR、O2-TPD-MS和化学分析方法,研究了催化剂结构和性能的变化.结果表明,催化剂在添加不同碱金属离子后,其结构和表面活性氧发生了很大变化.K离子可以改善催化剂的活性、提高反应选择性;Li离子能提高催化剂活性,但在相当宽的温度范围内使反应选择性下降;在693K以下,Cs离子对催化剂的活性和选择性均起抑制作用. 相似文献
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稀土对钒—钛苯酐催化剂活性的影响 总被引:2,自引:1,他引:2
在邻二甲苯气相氧化制苯酐的V2O5-TiO2催化剂中,添加少量La、Pr、Sm或Nd后,催化剂活性有不同程度的提高。本文应用FT-IR研究了氧化有后的苯酐催化剂,明显观察到在V-Ti苯酐催化剂中添加稀土后,V-O键的吸收峰发生红移,最大红移达到235cm^-1。苯酐催化剂加入稀土后,对分子的活化作用与催化活性剂评价的结果是一致的。 相似文献
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Hua Chang Jiang Ling Zeng Bin Long Yin 《中国化学快报》2007,18(5):585-587
Some Mo-V-Te-La catalysts with varied component were prepared by hydrothermal synthesis and dried with microwave method. The component of the catalyst were greatly affected the crystal structure and Raman spectrum. The phase in the catalysts was different when the Mo, V, and Te content varied. When the catalyst containing the same Mo, V content, due to the effect of dopant of Te element (V0.07 Mo0.93)5O14 became the main phase in the catalyst. The catalyst also showed good activity for the reaction of selective oxidation propane to acrolein and acrylic acid. 相似文献
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M-Na-P-Mo-V/SiO2系列催化剂对异丁烯氧化反应的催化性能 总被引:10,自引:0,他引:10
以浸渍法制备了M-Na-P-Mo-V/SiO2系列催化剂,并用FT-IR和TPR对催化剂进行了表征,考察了催化剂上的异丁烯化反应.结果表明,在空速900h-1和345℃的反应条件下,过渡金属的引入可提高甲基丙烯醛的选择性.其中Cu对催化性能的改善最佳,甲基丙烯醛选择性可达65.7%;而在Na-P-Mo-V/SiO2催化剂上,乙酸选择性可达50%,但甲基丙烯醛选性仅为4.1%.在催化剂中引入过渡金属时,Cu在提高甲基丙烯醛选择性的同时,也抑制了完全氧化产物COx的生成;Fe提高双键断裂产物和完全氧化产物选择性的同时,使甲基丙烯醛选择性下降;Zn对反应的影响不很大.TPR结果表明,在入Cu的催化剂中,Cu与杂多酸阴离子之间可能存在“溢流”作用. 相似文献
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V_2O_5/CeO_2催化剂上甲醇氧化一步法合成二甲氧基甲烷 总被引:1,自引:0,他引:1
采用溶胶-凝胶法制备了V2O5/CeO2催化剂,并用于甲醇氧化一步法合成二甲氧基甲烷(DMM)反应中.考察了V2O5含量对钒氧化物的存在状态、催化剂表面酸性、氧化-还原性及其催化甲醇氧化反应性能的影响.结果表明,V2O5含量为15%时钒氧化物呈单层分散,小于15%时以孤立或聚合态存在,大于20%时出现V2O5晶体,达到30%时出现CeVO4.当V2O5含量为15%时,较高的钒氧化物分散度使催化剂具有较强的氧化还原能力和较多的酸性中心,从而使催化剂具有较高的活性和DMM选择性. 相似文献
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A basic study for possible kinetic-catalytic methods in non-aqueous solvents with vanadium as a redox catalyst is described. The redox behaviour of the V(V)/V(IV) couple is studied by cyclic voltanimetry at a carbon electrode in acetonitrile. Vanadium oscillates between the two oxidation states without chemical side reactions, and is thus promising as a redox catalyst in non-aqueous media. The oxidizing power of the couple is increased with increasing p-toluenesulphonic acid concentrations and is decreased in the presence of solvents of increasing donor strength. The influence of common activators on the formal potential of the couple is discussed. 相似文献
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VPO催化剂制备条件对其催化甲苯氨氧化反应性能的影响 总被引:1,自引:0,他引:1
用浸渍法制备了负载型钒磷氧(VPO)催化剂,并以甲苯氨氧化合成苯甲腈为探针反应,考察了载体、还原剂、P/V比和V2O5负载量对催化剂性能的影响. 结果表明,大比表面积SiO2负载的VPO催化剂性能稳定,在高温下也具有较好的选择性. 采用不同还原剂制备的催化剂在反应一段时间后活性趋于一致,表明催化剂活性中心是在反应气氛下形成的. P/V比对催化剂活性和结构影响较大,P的加入破坏了V2O5的晶型结构,使磷酸盐物种从催化剂体相向表面聚集,减少了催化剂表面存在的过度氧化物种O-和O-2的数量,选择性氧化物种晶格氧(O2-)起主要氧化作用,提高了催化剂的选择性. V2O5负载量增大,催化剂活性提高,但生成苯甲腈的选择性降低. 表面单分子层覆盖的VOx可能是反应的活性位和选择性位. 相似文献
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In this work, we study the fabrication, structural characterization, and electrochemical activity of titanium‐supported binary Au? Ru catalysts for glucose oxidation. The catalysts including Au99Ru1, Au95Ru5, Au93Ru7 and Au88Ru12 were prepared by a hydrothermal method using formaldehyde as a reduction agent. The morphologies of the prepared Au? Ru catalyst structures are characterized by porous dendritic particles with roughened surfaces with nano‐sized flakes. Electrochemical catalytic activity of the binary Au? Ru catalysts towards glucose oxidation in alkaline solutions was investigated using cyclic voltammetry and chronoamperometry. All binary Au? Ru catalysts facilitate glucose oxidation at the lower potentials and deliver higher anodic oxidation currents compared to pure Au catalyst. Among them, the binary Au95Ru5 catalyst presents the most negative onset potential of ?0.872 V (vs. Ag/AgCl, 3 M KCl) for glucose oxidation in 0.1 M NaOH solution. For the Au95Ru5 catalyst, chronoamperometric data at the potential step of ?0.65 V (vs. Ag/AgCl,3 M KCl) exhibit a well linear dependence of the anodic oxidation current density on glucose concentration in the range of 0 to 15 mM glucose. 相似文献
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采用有机相法制备钒磷氧化物催化剂,通过空气或氧气气氛中不同时间的原位预处理以系统调变样品中V5+物种的含量及其状态,并考察对催化正丁烷选择氧化制马来酐的反应性能的影响。理化表征手段的结果表明,空气或氧气预处理改变了V物种的价态及V5+/V4+的相对含量,但对催化剂的比表面积和表面P/V比没有显著影响。表面V5+/V4+的合适比例及相应的结构状态可能在V5+-V4+物种之间产生较好的协同作用,从而获得较为理想的催化反应性能。 相似文献
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Yang JY Chen S Dougherty WG Kassel WS Bullock RM DuBois DL Raugei S Rousseau R Dupuis M Rakowski DuBois M 《Chemical communications (Cambridge, England)》2010,46(45):8618-8620
A bis-diphosphine nickel complex with tert-butyl functionalized pendant amines [Ni(P(Cy)(2)N(t-Bu)(2))(2)](2+) has been synthesized. It is a highly active electrocatalyst for the oxidation of hydrogen in the presence of base. The turnover rate of 50 s(-1) under 1.0 atm H(2) at a potential of -0.77 V vs. the ferrocene couple is 5 times faster than the rate reported heretofore for any other synthetic molecular H(2) oxidation catalyst. 相似文献
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