不同聚合物分散剂对Pt/SAPO-11催化剂性能的影响

采用浸渍法制备了经过不同聚合物分散剂处理的Pt/SAPO-11催化剂,并通过X射线衍射(XRD)、透射电子显微镜(TEM)、N₂吸附-脱附和NH₃程序升温脱附(TPD)等对催化剂的组织结构进行了表征。结果表明,分散剂不会破坏催化剂的结构,反而提高了其孔体积、孔径和比表面积,同时改变了沸石的酸强度和酸量,其中以聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂孔体积、孔径和酸性分布最佳。在固定床反应器上对不同分散剂处理的Pt/SAPO-11催化剂催化性能进行评价,结果表明聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂也表现出最佳的催化性能,麻风树油的加氢脱氧率高达99.45%,生物航空煤油组分收率和异构烷烃组分(C₈~C₁₆)的选择性分别达到了44.67%和56.37%。     

不同聚合物分散剂对Pt/SAPO-11催化剂性能的影响

采用浸渍法制备了经过不同聚合物分散剂处理的Pt/SAPO-11催化剂,并通过X射线衍射(XRD)、透射电子显微镜(TEM)、N₂吸附-脱附和N_H3程序升温脱附(TPD)等对催化剂的组织结构进行了表征。结果表明,分散剂不会破坏催化剂的结构,反而提高了其孔体积、孔径和比表面积,同时改变了沸石的酸强度和酸量,其中以聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂孔体积、孔径和酸性分布最佳。在固定床反应器上对不同分散剂处理的Pt/SAPO-11催化剂催化性能进行评价,结果表明聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂也表现出最佳的催化性能,麻风树油的加氢脱氧率高达99.45%,生物航空煤油组分收率和异构烷烃组分(C₈~C₁₆)的选择性分别达到了44.67%和56.37%。     

酸、盐处理对Pt/SAPO-11物化及其催化性能的影响

采用不同酸和盐浸渍处理SAPO-11分子筛,然后负载Pt制成改性的Pt/SAPO-11催化剂,用XRF、XRD、N_2吸附-脱附、SEM、NH_3-TPD和Py-IR对催化剂进行表征,分析其物理化学性能。结果表明,酸和盐处理没有破坏SAPO-11的骨架结构,还提高了催化剂的孔容、孔径、比表面积等性质,催化剂的酸性、酸量也明显发生了改变。在固定床反应器中,评价了改性的Pt/SAPO-11催化小桐子油一步加氢制异构烷烃性能;结合催化剂表征数据表明,颗粒粒径、比表面积、孔径、酸性和酸量影响催化剂的活性及产物分布。对比发现,经0.5 mol/L柠檬酸处理的Pt/SAPO-11催化剂孔径大小、酸性、B酸和L酸量分布合适,因此,一步加氢催化处理小桐子油性能优异;其中,生物航油组分(C_(8-16))的收率为32.47%,异构烷烃(C8-16)选择性为53.13%。     

M/Al2O3-CeO2（M=Pt-Ru，Ru，Pt）催化剂在甲胺催化湿式氧化中的活性与选择性

采用浸渍法制备了M/Al₂O₃-CeO₂（M=Pt-Ru,Ru,Pt）催化剂,并将其用于甲胺的催化湿式氧化反应（CWAO）.结果表明,Pt-Ru/Al₂O₃-CeO₂具有最佳活性和选择性.运用程序升温还原、X射线光电子能谱、X射线衍射、透射电子显微镜、N₂吸附和CO化学吸附等技术对催化剂的物化性质进行了表征.Pt组分的引入可有效提高双金属催化剂活性组分的分散度,从而明显提高了其催化性能.升降温过程中总有机碳（TOC）转化率与N₂选择性迟滞效应表明,甲胺CWAO遵循化学吸附-脱附机理.     

金属助剂对Pt/SAPO-11催化剂物化及异构性能的影响

通过浸渍法制备了Pt/SAPO-11催化剂,分步浸渍法制备了LaPt/SAPO-11、CePt/SAPO-11和SnPt/SAPO-11双金属催化剂。通过X射线衍射、低温氮物理吸附、氨程序升温脱附、氢气化学吸附和吡啶吸附红外等手段对所得样品进行了表征。实验结果表明,助剂的引入导致了催化剂的比表面积和微孔孔容降低,B酸量减少而L酸量增加,总酸量有所下降,Pt组分的分散度提高。在360℃时,对正庚烷的临氢异构化反应中,Pt/SAPO-11催化剂的正庚烷转化率为65.14%,C7异构体收率为61.67%;当分别加入La和Ce,Pt/SAPO-11的正庚烷转化率提高至77.40%和78.12%,C7异构体收率分别提高至69.72%和68.48%;而加入Sn后,Pt/SAPO-11的正庚烷转化率和C7异构体收率分别降至63.22%和59.09%。     

超声辅助浸渍法制备高分散Pt/CMK-3-US加氢脱萘催化剂

以CMK-3介孔碳作为载体,分别采用传统浸渍法、超声辅助浸渍法、载体硝酸处理法和表面活性剂辅助浸渍法备了Pt/CMK-3、Pt/CMK-3-US、Pt/CMK-3-HNO₃和Pt/CMK-3-CTAB催化剂,并通过表征和催化性能评价进行研究。表征方法包括XRD、BET、SEM、TEM和H₂-TPR,结果表明Pt/CMK-3中Pt分散性最差,Pt/CMK-3-HNO₃和Pt/CMK-3-CTAB中Pt的分散度较好,但是HNO₃对介孔碳的孔道结构有破坏作用,且Pt/CMK-3-HNO₃和Pt/CMK-3-CTAB中的介孔碳的表面性质具有明显变化,只有超声法可以在很好地保持CMK-3的孔道结构和表面性质的基础上提高铂的分散度,Pt的粒径在3 nm左右。萘加氢催化性能评价结果表明Pt/CMK-3-US的催化加氢活性及产物选择性高于Pt/CMK-3,且明显高于Pt/CMK-3-HNO₃和Pt/CMK-3-CTAB。萘转化率可以达到98%以上,十氢萘选择性可以达到95%以上。     

介孔交联蒙脱土固体酸催化剂的结构与性能

采用溶胶凝胶法制备介孔钛交联蒙脱土，再采用SO₄^2-和CeO₂进行两次改性，然后以之为载体，制备铜基交联蒙脱土介孔固体酸催化剂。 催化剂的结构通过BET、XRD、TPR、Py-IR、FTIR、XPS和SEM等手段进行表征，并研究了它们在富氧条件下对丙烯选择还原NO的催化性能。结果表明，钛交联剂能很好地撑开蒙脱土的土层，形成良好的介孔结构，其孔径分布集中在3～7 nm，并且使制得的交联蒙脱土载体的比表面积明显增大；SO₄     

Fe3O4修饰的Pt-Ru/C纳米催化剂的制备及其在无溶剂条件下邻氯硝基苯选择性加氢的催化性能

采用浸渍法制备了一系列Pt/Ru质量比不同的Fe₃O₄修饰的Pt-Ru/Fe₃O₄/C催化剂, 运用透射电镜(TEM)、能量弥散X射线谱(EDX)、X射线光电子能谱(XPS)、X射线粉末衍射(XRD)等手段对Pt-Ru/Fe₃O₄/C一系列催化剂进行了表征, 并考察了Pt/Ru质量比不同对催化剂Pt-Ru/Fe₃O₄/C在无溶剂条件下催化邻氯硝基苯(o-CNB)选择性加氢制备邻氯苯胺(o-CAN)催化性能的影响. 研究结果表明, 催化剂的催化活性和对目标产物的选择性跟活性组分Pt、Ru比例有关. 随着Pt/Ru比例的减小, 目标产物o-CAN的选择性有所升高, 然而反应物o-CNB的转化率有所下降. 当Pt/Ru的质量比为2时, o-CNB的转化率降为76.5%, 而目标产物o-CAN的选择性仍然为100%. 与此同时, 我们还对Pt-Ru/Fe₃O₄/C催化剂高的催化活性和目标产物的高选择性可能的原因进行了分析.     

不同金属改性HZSM-5催化剂的甲醇羰基化反应性能

以具有酸性特性的HZSM-5分子筛为载体,结合金属本身具有的羰基化活性,可以更好的提高羰基化反应效率。采用负压沉积沉淀法对HZSM-5催化剂进行Pt、Pd、Cu、Au、Zn改性,制备不同酸度的催化剂。利用X射线衍射、NH₃程序升温脱附、吡啶吸附FTIR、N₂吸附-脱附和X射线荧光分析研究了不同金属对催化剂物理化学性质及不同负载型HZSM-5催化剂对甲醇羰基化产物的分布和产率的影响。结果表明,不同金属的引入对HZSM-5催化剂的比表面积、孔径和孔体积影响较小,但明显地改变了催化剂表面的酸强度。Pt、Au、Zn和Cu改性后的催化剂更有利于甲醇羰基化反应的进行,其中Cu/HZSM-5催化剂在400℃的甲醇转化率高达90.2%,比HZSM-5催化剂的甲醇转化率高12%,但目标产物的选择性比Pt/HZSM-5及Au/HZSM-5的低。总的来看,金属的引入改变了催化剂表面Brønsted酸（B酸）和Lewis酸（L酸）中心的数量,甲醇的转化率随总酸量的增加而增加,催化剂表面B酸与L酸的比例在0.3~0.5时,催化剂表现出更好的羰基化作用。     

Ce掺杂对碳纳米管负载Mn催化剂结构及SCR反应性能的影响

采用等体积浸渍法制备多壁碳纳米管(MWCNTs)负载Ce-Mn的催化剂,考察了Ce掺杂对Mn/MWCNTs催化剂上NH₃选择性催化还原(SCR)NO_x反应活性的影响.并运用透射电镜扫描、N₂吸附-脱附、程序升温还原、X射线光电子能谱、X射线衍射等手段,重点考察了Ce掺杂对Mn/MWCNTs催化剂结构性质的影响.结果表明,Ce掺杂能显著提高催化剂的SCR活性,其活性增量随着Ce含量的增加先增大后减小;当Ce/Mn为0.6时,催化剂活性最佳.表征结果显示,Mn/MWCNTs中添加Ce后,金属氧化物在MWCNTs上的分散程度提高;催化剂的比表面积和孔体积增大,平均孔径减小;氧化能力提高;表面氧含量增加,Mn化合价升高;结晶度降低,Mn主要以无定形或微晶形式存在,Ce主要以CeO₂物相存在.     

Pt/SAPO-11催化剂载体的改性对正十四烷临氢转化性能的影响

以Pt/SAPO-11双功能催化剂为基础,对催化剂载体进行柠檬酸、炭黑改性,以正十四烷为模型化合物,通过催化剂表征和反应评价,探索了催化剂载体的改性对正十四烷临氢转化性能的影响。结果表明,异构化产物以单甲基异构物为主,改性没有改变催化剂的酸强度,但使得酸浓度有所下降。通过柠檬酸调变催化剂的酸性使得催化剂的低温催化活性显著提高,采用炭黑扩孔改性,有效改善了催化剂的传质性能,提高了催化剂的单甲基异构体选择性。柠檬酸和炭黑改性的催化剂裂化产物均以C6为主,改性并没有改变SAPO-11分子筛的孔道限制效应,裂化产物呈现一定的择型效应,裂化产物分布呈现出不对称分布的特点。     

Comparison ofn-decane hydroconversion with Pt/SAPO-5 and Pt/SAPO-11 catalysts

The product distributions from bifunctional conversion ofn-decane over Pt/SAPO-5 and Pt/SAPO-11 catalysts are compared in detail. Selectivities in decane reaction vary largely with the catalyst employed: Pt/SAPO-11 produces high yields of feed isomers, whereas Pt/SAPO-5 gives high yields of cracked products and only under mild reaction conditions are isodecanes the main products obtained. These selectivities seem to be determined by the structure of the catalyst.     

Synthesis and characterization of SAPO-11 molecular sieves from alcoholic systems

Summary SAPO-11 molecular sieves were synthesized from aqueous and nonaqueous systems by using different alcoholic solvents and their physicochemical properties were compared. The SAPO-11 samples synthesized from alcoholic systems had larger external surface area, higher Si contents and higher acidity than those of the sample synthesized from the aqueous system. Thereby, loaded with 0.5 wt.%Pt, the resulting Pt/SAPO-11 catalysts synthesized from alcoholic systems exhibited higher catalytic activities and selectivity for n-dodecane hydyroisomerization. Among the catalysts synthesized from alcoholic systems, the Pt/SAPO-11 catalyst synthesized from polybasic alcohol systems possessed the highest catalytic activities.     

Selective hydroisomerization of n-dodecane over platinum supported on zeolites

In this study, in order to develop catalysts for the selective isomerization of higher paraffin, the hydroisomerization reaction of n-dodecane was performed as a model reaction. Pt/ZSM-48, Pt/HZSM-5, Pt/HY, and Pt/SAPO-11 were examined for the selective hydroisomerization of n-dodecane. The catalysts were characterized via X-ray powder diffraction, N₂ adsorption, and the temperature-programmed desorption of ammonia. Among the catalysts studied, the Pt/HZSM-48 catalyst exhibited the best isomerization selectivity in the hydroisomerization reaction of n-dodecane, which is attributed to the moderate acid sites and medium-sized pores present in the HZSM-48. The highest iso-dodecane yield was obtained at a reaction temperature of 280 °C in the Pt/HZSM-48 catalyst. The optimal selectivity of the n-dodecane hydroisomerization over the Pt/SAPO-11 catalyst was obtained at approximately 300 °C, which was slightly higher than that of the Pt/HZSM-48 catalyst.     

SAPO-11/Beta复合分子筛的合成及其异构化性能研究

以Beta分子筛为硅源通过水热合成法合成了SAPO-11/Beta复合分子筛,采用X射线衍射、N2物理吸脱附、扫描电镜、透视电镜-能谱分析、固体核磁及吡啶红外等方法对单分子筛、复合分子筛和机械混合分子筛的物化性质进行了表征.以正十二烷为模型化合物,在固定床反应器上考察了铂负载型分子筛催化剂的异构化性能.结果表明,复合分子筛的物理化学性质明显不同于单分子筛和机械混合分子筛,其呈现核壳结构,SAPO-11和Beta间存在化学作用,使得复合分子筛具有适宜的B酸分布.在正十二烷异构化反应中,复合分子筛催化剂的异构化性能优于单分子筛催化剂和机械混合分子筛催化剂,多支链异构体收率高.     

Selective hydrogenation of o-chloronitrobenzene (o-CNB) over supported Pt and Pd catalysts obtained by laser vaporization deposition of bulk metals

Carbon nanotubes (CNTs), γ-alumina (γ-Al₂O₃) and silica (SiO₂) supported Pt and Pd catalysts were produced by laser vaporization deposition of respective bulk metals. The catalysts were characterized by inductive coupled plasma emission spectrometer (ICP), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The catalytic properties of the catalysts were investigated in the liquid phase hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) under 333 K and 1.0 MPa hydrogen pressure. The results show that the catalytic properties are greatly affected by the supports. Pt/CNTs catalyst exhibits the best catalytic performance among the Pt-based catalysts, producing o-CAN with 99.6% selectivity at complete conversion. Pd/CNTs catalyst exhibits the best catalytic performance among the Pd-based catalysts, giving o-CAN with 95.2% selectivity at complete conversion. For Pt-based catalysts, geometric effect and the textures and properties of the supports play important roles on catalytic properties. On the other hand, geometric effect, electronic effect and the textures and properties of the supports simultaneously influence the catalytic properties of the Pd-based catalysts. In addition, hydrogenolysis of the C–Cl bond can be well inhibited over all catalysts prepared by laser vaporization deposition.     

In-situ Synthesis of Gallium-Containing SAPO-11 Molecular Sieves and Superior Catalytic Performance of Their NiWS Supported Catalysts for Hydroisomerization of n-Hexadecane

In order to prepare a high-performance SAPO-11 (silicoaluminophosphate-11) based non-noble metal supported catalyst for the hydroisomerization of long-chain n-alkanes, gallium-modified SAPO-11 molecular sieve was successfully synthesized by the in-situ synthesis method, and the NiWS supported catalyst was prepared for the hydroisomerization of n-hexadecane. The effects of Ga-modification on the physicochemical properties of SAPO-11 molecular sieve, the active phase properties, and the catalytic performance of the catalyst were studied. Through a series of physicochemical characterizations, it was found that the introduction of Ga increased the mesoporous volume of SAPO-11 molecular sieve, reduced their acid density and strength, but improved the amount of medium-strong Brønsted acid. The Ga-modification weakened the interaction between the active metals and the support, increased the sulfidation degree of active metals, and increased the stacking number and dispersion of active phase. The results of catalytic performance evaluation showed that the catalytic activity and isomerization selectivity of the Ga-modified SAPO-11 molecular sieve based catalysts were improved, and the yield of i-hexadecane of NiW/2Ga-SAPO-11 was the highest, which was 40.30 % higher than that of NiW/SAPO-11. By analyzing the distribution of isomeric products, it was found that the Ga-modified SAPO-11 molecular sieve was helpful in improving the hydroisomerization depth of n-hexadecane over the catalyst.