A highly efficient synthesis approach of supported Pt-Ru catalyst for direct methanol fuel cell

A highly efficient synthesis approach of urea-assisted homogeneous deposition (HD) coupled with H₂ reduction has been employed to synthesize carbon-supported Pt-Ru catalyst with high metal loading of 60 wt%. The urea-assisted HD method permits in situ gradual and homogeneous generation of hydroxide ions, resulting in smaller Pt-Ru nanaoparticles deposited on the carbon support along with better particle size distribution compared with the catalyst prepared by the conventional impregnation-NaBH₄ reduction. The Pt-Ru catalyst prepared by the HD-H₂ method has demonstrated greatly enhanced catalytic activity towards methanol oxidation and much improved fuel cell performance compared with the one prepared by impregnation-NaBH₄ reduction. HD-H₂ method is simple with mild synthesis condition, but provides very efficient approach for the preparation of Pt-based catalysts for fuel cells.     

Semi-indirect synthesis of LPG from syngas: Conversion of DME into LPG

Efficient conversion of dimethyl ether (DME) into liquefied petroleum gas (LPG) with a hybrid catalyst is a novel method for semi-indirect synthesis of LPG fuel from syngas. The hybrid catalysts consisting of zeolite and hydrogenation catalyst were investigated in a fixed bed reactor. Experimental results demonstrated that the hybrid catalyst consisting of (Pd/SiO₂) and USY efficiently converted DME into LPG and restrained decomposition of DME into CO and H₂. With that catalyst, the one through conversion of DME reached about 100%, almost no CO and CO₂ were produced and selectivity for LPG was more than 65%.     

Direct synthesis of LPG from syngas derived from air-POM

Direct synthesis of liquefied petroleum gas (LPG) from a low-cost syngas derived from partial oxidation of methane with air (air-POM) was investigated over a hybrid catalyst consisting of methanol synthesis catalyst and Pd-modified Y-zeolite. The hybrid catalyst demonstrated a high activity and more than 73% selectivity for LPG fraction. BET, NH₃-TPD and TPO-MS were carried out to study the properties of Pd-Y before and after reaction. The results indicated that coke deposition on Pd-Y was the main contribution to the slow deactivation of hybrid catalyst.     

HZSM-5对生物质合成气一步法合成LPG的影响

研究了MeLi与HZSM-5型分子筛不同质量配比混合制备的合成液化石油气(LPG)催化剂的性能,评价了不同硅铝比(硅铝摩尔比为25、38、50)HZSM-5型分子筛酸性对LPG合成的影响,结果表明,MeLi与HTZSM-5型分子筛质量比在2∶1时对合成LPG最佳,随着分子筛硅铝摩尔比的降低,分子筛的酸性增强,CO单程转化率提高.HZSM-5型分子筛在合成LPG过程中,硅铝比为38时最佳,空速在1 500 h->时,CO转化率为84.87%,碳氢化合物产物中C3 C4所占比例(摩尔分数)最高,达到58.21%.通过计算,每吨干基生物质气化得到合成气,经合成单程转化可得到0.0786 t LPG,联产电力607 kWh.     

钌基催化剂用于直接法合成气制低碳烯烃反应

以γ-Al₂O₃为载体,通过等体积浸渍法制备钌基催化剂,用其进行催化CO加氢,研究制低碳烯烃反应中钌基催化剂的催化性能,考察催化剂的焙烧温度、工艺条件及碱金属助剂Na对钌基催化剂CO加氢反应的影响。结果发现,焙烧温度400 ℃制备的钌基催化剂具有最大的比表面积,在反应温度220 ℃、反应压力1.0 MPa和空速1 500 mL·(h·g)^-1条件下,可以保证较高的CO转化率及低碳烯烃选择性。碱金属助剂Na提高了催化剂催化活性,Na质量分数为4%6%时,钌基催化剂表现出最佳的CO转化率及低碳烯烃选择性。     

A highly active and stable Fe-Mn catalyst for slurry Fischer–Tropsch synthesis

A highly stable and active Fe-Mn catalyst for slurry Fischer–Tropsch synthesis (FTS) was prepared and scaled up for the application in the industrial pilot plant at Institute of Coal Chemistry (ICC), Chinese Academy of Sciences (CAS). One Lab-scale catalyst and one scaled-up catalyst are introduced in the present paper. The particle size of the Lab-scale catalyst is about 5–15 μm, while it is increased to 30–90 μm for the scaled-up catalyst. Simultaneously, the morphology of the catalyst was greatly improved after the catalyst being scaled up. Both the Lab-scale and scale-up catalysts show high FTS activity. CO conversion of the Lab-scale catalyst and the scaled-up one are over 70.0% (H₂/CO = 0.67, 275 °C, 1.5 MPa and 3000 h⁻¹) and 55.0% (H₂/CO = 0.67, 260 °C, 1.5 MPa and 2000 h⁻¹), respectively. The catalysts also possess excellent stability, no obvious deactivation was observed during stable run of 4200 h and 1200 h on stream for the two catalysts. However, the Lab-scale catalyst produced more methane (about 8–10 wt%) and C_2–4 (22–30 wt%) and less C5⁺ hydrocarbon (55–70 wt%). Meanwhile, the hydrocarbon distribution of the catalyst was greatly improved for after the catalyst being scaled up, and the distribution of hydrocarbon products become much preferable. The selectivity to methane was well controlled at about 5 wt%, and the sum of and was increased to 91–93 wt%. On the whole, the scaled-up catalyst satisfies the requirements of the application for FTS in the industrial pilot plant of slurry bubble column reactor (SBCR) at ICC, CAS.     

A highly efficient catalyst for direct synthesis of methyl acrylate via methoxycarbonylation of acetylene

A non-petroleum approach for the catalytic synthesis of methyl acrylate via methoxycarbonylation of acetylene with carbon monoxide and methanol as nucleophilic reagent has been studied under various conditions. Pd(OAc)₂/2-PyPPh₂/p-tsa was found to be a highly efficient catalytic system. The types of phosphorus ligands and their concentration was a determinative factor for catalytic activity. Mono-dentate phosphorus ligand such as triphenylphosphine has no activity while 2-(diphenylphosphino)pyridine with a mixed N-P bidentate structure has an excellent activity. Catalytic performance of acids depends on their acidic strength and coordinative property. Among all acidic promoters, p-toluenesulfonic acid displayed an excellent performance. Other parameters such as solvent polarity and initial pressure of carbon monoxide have also important influences on the hydroesterification of acetylene. It is beneficial for the reaction that the solvents have a high polarity. At low pressure of carbon monoxide, to high active palladium catalyst, the reaction easily proceeded. However, at high pressure of carbon monoxide, acetylene will transfer from solution to gas phase, resulting in lower conversion of acetylene. In addition, due to steric hindrance of alcohols, methanol has a highest activity in hydroesterification of acetylene in low carbon alcohols. Under the optimal reaction conditions, 99.5% of acetylene conversion and 99.7% of selectivity toward methyl acrylate as well as 2,502 h^?1 TOF were achieved.     

Liquid phase methanol and dimethyl ether synthesis from syngas

The Liquid Phase Methanol Synthesis (LPMeOH^TM) process has been investigated in our laboratories since 1982The reaction chemistry of liquid phase methanol synthesis over commercial Cu/ZnO/Al₂O₃ catalysts, established for diverse feed gas conditions including H₂-rich, CO-rich, CO₂-rich, and CO-free environments, is predominantly based on the CO₂ hydrogenation reaction and the forward water-gas shift reactionImportant aspects of the liquid phase methanol synthesis investigated in this in-depth study include global kinetic rate expressions, external mass transfer mechanisms and rates, correlation for the overall gas-to-liquid mass transfer rate coefficient, computation of the multicomponent phase equilibrium and prediction of the ultimate and isolated chemical equilibrium compositions, thermal stability analysis of the liquid phase methanol synthesis reactor, investigation of pore diffusion in the methanol catalyst, and elucidation of catalyst deactivation/regenerationThese studies were conducted in a mechanically agitated slurry reactor as well as in a liquid entrained reactorA novel liquid phase process for co-production of dimethyl ether (DME) and methanol has also been developedThe process is based on dual-catalytic synthesis in a single reactor stage, where the methanol synthesis and water gas shift reactions takes place over Cu/ZnO/Al₂O₃ catalysts and the in-situ methanol dehydration reaction takes place over -Al₂O₃ catalystCo-production of DME and methanol can increase the single-stage reactor productivity by as much as 80%. By varying the mass ratios of methanol synthesis catalyst to methanol dehydration catalyst, it is possible to co-produce DME and methanol in any fixed proportion, from 5% DME to 95% DMEAlso, dual catalysts exhibit higher activity, and more importantly these activities are sustained for a longer catalyst on-stream life by alleviating catalyst deactivation.     

铜基甲醇合成催化剂失活原因的探讨

采用加压微型反应器和化学分析、原子吸收光谱法、X 射线荧光分析、X 射线衍射峰宽化法和其它分析方法对工业使用前后的铜基甲醇合成催化剂M K101 进行了分析和讨论。探讨了该催化剂的失活原因。     

煤制化学品：合成气直接制低碳烯烃催化剂研究进展

低碳烯烃是重要的化工原料,直接法合成气制低碳烯烃是非石油路线生产烯烃的新途径。本文首先介绍了直接法合成气催化转化制烯烃的两种工艺路线,即双功能催化剂反应偶联和费-托合成路线制低碳烯烃;接着对CO加氢反应的热力学进行了分析。重点从催化剂活性相、尺寸效应、助剂、金属载体相互作用等方面对合成气直接法制低碳烯烃催化剂的研究进展以及CO加氢反应机理进行了综述。文章指出：在基础研究方面,反应机理仍待进一步明晰,催化剂的开发应聚焦于对O/P及产物链长的精准调控;工业化方面,要考虑到真实的工业化反应环境与实验室反应之间的差异,同时要注意与上下游的产业联合。     

A novel silicalite-1 zeolite shell encapsulated iron-based catalyst for controlling synthesis of light alkenes from syngas

A well-designed zeolite capsule catalyst with a Core (Fe/SiO₂)-Shell (Silicalite-1) structure was successfully prepared by zeolite seeding and then zeolite shell growing via secondary hydrothermal method. The characterization on this zeolite capsule catalyst indicated that it had a compact, defect-free zeolite shell enwrapping core catalyst tightly. The application of this zeolite capsule catalyst was the direct synthesis of light alkenes from syngas via Fischer–Tropsch synthesis (FTS) reaction. This zeolite capsule catalyst exhibited excellent abilities compared with the traditional FTS catalyst, both on the controlled synthesis of the desirable light alkenes and the suppressing formation of the undesired long-chain hydrocarbons.     

生物质气一步法合成二甲醚双功能催化剂失活研究

概述了生物质气一步法合成二甲醚双功能催化剂的热失活、中毒失活的原因及其解决方案。提出了载体是二甲醚合成催化剂需要突破的重点,将整体式催化剂载体应用二甲醚合成中,不失为一个新的研究方向。     

Pd-Co/CNT复合催化剂的制备及甲醇电氧化性能

以Pd Cl₂和Co(NO₃)₂为原料，采用分步乙二醇还原法制备了多壁碳纳米管负载Pd-Co复合纳米催化剂Pd-Co/CNT。利用TEM、XRD和XPS对催化剂的结构进行了表征，考察了其甲醇电氧化性能。结果显示，Co的引入使Pd催化剂的分散性得到改善，其电化学表面积可达39.7 m²/g。循环伏安测试表明，当Pd∶Co物质的量比为1∶0.2时，Pd-Co/CNT的甲醇氧化峰电流密度约为Pd/CNT的2.7倍。计时电流结果表明，Co的添加使催化剂的活性衰减比例由Pd/CNT的63.8%降至54.2%，显示出较强的抗中毒能力。Pd-Co复合催化剂性能的改善归因于Pd与Co之间的协同相互作用。     

Preparation and characterization of carbon nanotube-promoted Co–Cu catalyst for higher alcohol synthesis from syngas

A cobalt–copper catalyst promoted by “herringbone-type” multiwalled carbon nanotubes (CNTs) was developed. This catalyst displayed excellent performance for higher alcohol synthesis (HAS) from syngas, with the (C_2–8-alc. + DME)-STY reached 760 mg/(g·h) under the reaction conditions of 5.0 MPa and 573 K, which was 1.78 times that of the CNT-free host, Co₃Cu₁. The addition of a minor amount of the CNTs to the Co₃Cu₁ host did not cause a marked change in apparent activation energy for the HAS, but led to an increase at the surface of the catalyst of the concentration of catalytically active Co-species, CoO(OH), a kind of surface Co-species related closely to the selective formation of the higher alcohols. Excellent adsorption performance of this kind of CNTs for H₂ generated a surface micro-environment with a high concentration of H-adspecies on the functioning catalyst, thus increasing the rate of surface hydrogenation reactions in the HAS. Moreover, synergistic action of the high surface-concentration H-adspecies with CO₂ in the feed-gas led to a greater inhibition for the WGS side-reaction. All these factors contribute considerably to an increase in the yield of alcohols.     

LC308合成甲醇催化剂的研制

通过实验室研究和工厂模拟试验 ,结果表明 :新研制的 L C30 8甲醇催化剂与工厂使用的几种牌号的甲醇催化剂相比具有初活性、CO单程转化率、粗醇中甲醇含量高等特点 ,催化剂综合性能有明显提高。如在相同操作工况的工业装置中使用 ,可使甲醇产量提高 5 %～ 10 %。同时副产蒸汽增多 ,甲醇精制过程单位能耗降低。     

含CO2合成气低温合成甲醇的研究

以含CO₂的合成气为原料,Cu-Zn基催化剂,醇溶剂,低温、低压（443 K、3.0 MPa）下合成甲醇。考察了时间、溶剂和催化剂对反应的影响。结果表明,随着反应时间的增加,碳的总转化率、甲醇选择性及收率均逐渐增加;醇溶剂参与反应,但并不被消耗,起到助催化作用,且2-丁醇溶剂表现出较高的反应活性;ZnO、Y₂O₃、La₂O₃、MgO和Al₂O₃作为载体制得的Cu/M_xO_y催化剂,Cu/ZnO呈现出较高的反应活性;稀土元素La作为助剂,能提高Cu-Zn基催化剂的活性,当使用n(Cu)∶n(Zn+La)=1∶1,且n(Zn)∶n(La)=3∶2的Cu/ZnO/La2O3催化剂进行甲醇合成反应时,碳总转化率、甲醇的选择性和收率均高于Cu/ZnO催化剂。     

影响甲醇合成催化剂时空收率的因素

研究温度、压力、空速、原料气组成等对甲醇合成催化剂时空收率的影响 ,以及催化剂使用前后的时空收率 ,CO、 CO2 转化率 ,粗甲醇含水量 ,粗甲醇中杂质的变化规律。并对实验结果进行了数学关联和综合分析     

合成气催化合成甲醇Cu基催化剂的研究

介绍了合成气催化合成甲醇Cu基催化剂的制备方法——沉淀法,并指出在制备过程中为避免催化剂失活应注意的问题。介绍了3种Cu基催化剂的活性中心模型,分别为：Cu0,Cu＋及Cu0-Cu＋模型。详细介绍了催化剂合成甲醇的反应机理：CO机理,CO2机理和CO与CO2混合反应机理。最后对甲醇合成催化剂制备提出了改进意见。     

液化石油气轿车尾气净化催化剂的研制

针对燃料为液化石油气轿车尾气排放特点,使用耐高温氧化铝载体材料和高性能的铈锆氧化物材料,设计了活性组分为贵金属Pd和Rh不同配比的净化催化剂,用BET、TPR和XRD等手段进行表征,研究了催化剂的空燃比特性和起燃温度特性,结果表明,催化剂具有较好的活性和高温稳定性。     

Polyol synthesis of highly active PtRu/C catalyst with high metal loading

Highly loaded PtRu/C catalyst with high activity toward methanol electrooxidation was synthesized via a modified polyol process. XRD patterns indicated that the prepared catalyst was highly alloyed and TEM results showed that the metal nanoparticles were small and uniformly distributed on the carbon support despite the high metal loading. EDX results suggested that the two metals distributed uniformly in the catalyst. Electrochemical characterization and single cell test jointly showed that the prepared 40-20 wt.%PtRu/C catalyst possessed high activity toward methanol electrooxidation.