活性炭材料对镍基催化剂乙醇气相羰化性能的影响

采用浸渍法制备了负载在竹炭(BC)、柱状煤质炭(CYC)、果壳炭(FC)、木质炭(WC)和椰壳炭(CC)上的5种Ni基催化剂,考察了镍分散度、还原性能及催化乙醇气相羰化制丙酸的性能.用N2物理吸附法、X射线光电子能谱和程序升温脱附等方法研究了活性炭的孔结构特性、表面含氧官能团种类和数量.结果表明,Ni/CC的羰化活性最高,乙醇转化率和丙酸选择性分别为96.1%和93.2%,而Ni/BC的羰化活性最低,乙醇转化率和丙酸选择性分别为63.0%和32.7%.催化剂催化羰化性能与其载体活性炭材料的性质密切相关.     

K促进的Fe/椰壳炭催化剂对甲烷氮气常压合成氨性能的影响

采用等体积浸渍法制备了一系列催化剂用于甲烷氮气常压合成氨反应.对Si O2、γ-Al2O3、煤质柱状炭、椰壳活性炭为载体的Fe基催化剂的活性评价结果显示椰壳炭载体最优;通过对Zr、Ce、K等多种助剂的筛选,发现K促进的Fe基催化剂氨生成速率最高.利用XRD、SEM、BET等手段对载体和催化剂进行表征,结果表明椰壳炭具有规则孔道且孔容增大,催化剂还原后有新晶相KFe O2生成.最后在固定床微分反应器中,考察了常压合成氨催化剂的负载顺序及最优工况.结果表明,在常压700℃、VCH4/VN2=2/1、空速为2 800 m L/h时,催化剂3%K-5%Fe/椰壳炭的氨生成速率最高可达1.04×10-6mol·g-1·s-1,是现有文献值的83.5倍,将具有深远的工业应用前景.     

表面含氧基团对AuCl3-CuCl2/C双组分非汞催化剂催化性能的影响

采用HNO₃氧化及在He气氛围经不同温度焙烧处理椰壳活性炭, 以此活性炭为载体, 通过浸渍法制得AuCl₃-CuCl₂/C双组分非汞催化剂, 并用于乙炔氢氯化反应评价. 结果表明, 分别以HNO₃处理、 未处理和400 ℃焙烧处理活性炭为载体的催化剂乙炔转化率最高分别可达98%, 96%和90%; 而以700和1000 ℃焙烧的活性炭为载体的催化剂反应4 h后乙炔转化率急剧下降为30%. 考察了活性炭表面的含氧基团(尤其是羟基)对Au基催化剂的催化性能的影响.     

椰壳炭磺酸催化环氧苯乙烷的醇解反应

利用椰壳制备的固体炭磺酸催化环氧苯乙烷的醇开环反应.考察了椰壳炭磺酸催化剂用量,溶剂对产率的影响.比较了椰壳炭磺酸与磺酸树脂、对甲苯磺酸和硫酸氢钠等传统磺酸型催化剂在该反应中的催化性能.结果表明,椰壳炭磺酸是一种绿色高效的固体酸催化剂.     

镍基催化剂上苯酐选择性加氢合成苯酞

分别以SiO2,TiO2,γ-Al2O3,TiO2-SiO2和TiO2-Al2O3为载体,以硝酸镍为镍源,采用等体积浸渍法制备了一系列镍基催化剂,并将其用于苯酐选择性加氢合成苯酞反应.结果表明,以TiO2-SiO2为载体制备的镍催化剂上Ni0活性组分分散度较高,催化剂表现出较高的活性和苯酞选择性.在此基础上,采用溶胶-凝胶法制备出了一系列Ni/TiO2-SiO2催化剂,考察了催化剂制备中各因素(包括溶剂、焙烧温度、还原温度和镍前驱体类型等)对其催化苯酐加氢反应性能的影响.结果表明,将镍前驱体溶于不同溶剂制备的催化剂性能差异很大,其中以水为溶剂制备的催化剂活性较高,且性能优于等体积浸渍法制备的相应催化剂.焙烧温度和还原温度过高会导致活性组分镍晶粒度变大,致使催化剂活性明显降低.镍源对Ni/TiO2-SiO2催化剂的性能影响较大,以硫酸镍为镍源制备的催化剂几乎无活性,而以氯化镍和硝酸镍为镍源制备的催化剂表现出较高的催化活性和选择性,其中以氯化镍制备的催化剂性能略高于硝酸镍,苯酐转化率为100%,苯酞选择性为88.5%.     

炭材料负载金属催化剂催化硅氢加成反应进展

炭材料具有比表面积大、孔径可调、取材广泛等优点,以其为载体负载金属活性组分制备硅氢加成催化剂极具发展前景.我们详细总结了近20年不同炭材料如活性炭、石墨与石墨烯、碳纳米管、富勒烯、卡宾等在硅氢加成反应中负载金属催化剂的制备方法、催化性能以及可能的催化机理,并对有望应用到该反应的新型炭材料载体进行了对比与展望.认为未来硅氢加成炭负载型催化剂的研究可聚焦于(1)探寻新型双金属活性组分以进一步提高催化活性;(2)研发更具优势的金属配体,明晰配体与载体、配体与金属之间的相互作用关系以提高催化选择性与稳定性;(3)结合科学可靠的催化机理研究,以期研发出更符合可持续发展要求的炭负载型硅氢加成金属催化剂,可使硅氢加成反应基本实现原子经济性.     

活性炭载体对聚合物电解质膜燃料电池中炭载铂电催化剂性能的影响

分别以松木炭和Vulcan XC-72炭为载体制得载铂电催化作用，在聚合物电解质膜燃料电池（PEMFC）中对其性能进行了比较。结果表明：Vulcan XC-72炭作载体的电催化剂性能显著优于松木炭作载体的电催化剂，利用多种分析对活性炭的物理和表面化学性质进行了系统的研究，发现活性炭的孔径、电导率和表面含氧基团和电催化剂性能有很大的影响。     

一种酸处理炭载体负载的铱基催化剂及其制备方法和应用

一种用于甲醇经羰基化制乙酸甲酯的酸处理载体负载催化剂及其制备方法。由主活性组分和载体两部分组成,主活性组分为铱和过渡金属或其氧化物助剂,其含量为催化剂重量的0.01%～5.0%和0.1%～30%;载体为酸处理炭载体,包括经过酸处理椰壳炭或杏壳炭及其他酸处理的碳化载体。酸处理的目的在于提高乙酸甲酯选择性,降低甲烷。按本发明提供一种通过浸渍法将金属负载在酸处理载体上,形成Ir基催化剂。在固定床反应器中,在一定的温度和压力以及本催化剂作用下,CH_3OH/CO可高活性、高选择性地转化为乙酸甲酯,且降低了甲烷的选择性。     

碳改性对Ni/Al2O3催化剂顺酐加氢合成γ-丁内酯反应性能的影响

通过热解蔗糖/Al2O3前驱体的方法制备了炭包覆改性Al2O3(CCA)载体,并采用等体积浸渍制备了负载量17 %的镍基催化剂.对载体及相应催化剂进行了TPO-MS、N2物理吸附、TPR、XRD等测试表征,并考察了催化剂顺酐(MA)加氢合成γ-丁内酯(GBL)的反应性能.结果表明,适量炭的引入改变了载体Al2O3的表面性质,使金属-载体相互作用减弱,活性组分镍的分散度提高,催化剂在MA加氢反应中表现出高的GBL选择性.当Al2O3中引入8.9 %的炭时,催化剂表现出最高的催化活性,在210 ℃,5 MPa氢气压力下反应3 h时,MA转化率达98%以上,GBL选择性达91.71 %.     

炭改性对Ni/Al_2O_3催化剂顺酐加氢合成γ-丁内酯反应性能的影响

通过热解蔗糖/Al2O3前驱体的方法制备了炭包覆改性Al2O3(CCA)载体,并采用等体积浸渍制备了负载量17%的镍基催化剂.对载体及相应催化剂进行了TPO-MS、N2物理吸附、TPR、XRD等测试表征,并考察了催化剂顺酐(MA)加氢合成γ-丁内酯(GBL)的反应性能.结果表明,适量炭的引入改变了载体Al2O3的表面性质,使金属-载体相互作用减弱,活性组分镍的分散度提高,催化剂在MA加氢反应中表现出高的GBL选择性.当Al2O3中引入8.9%的炭时,催化剂表现出最高的催化活性,在210℃,5 MPa氢气压力下反应3 h时,MA转化率达98%以上,GBL选择性达91.71%.     

Synthesis of carbon nanotubes by catalytic pyrolysis method with Feitknecht compound as precursor of NiZnAl catalyst

Carbon nanotubes are synthesized by catalytic pyrolysis method with a kind of new type catalyst--nickel-zinc-alumina catalyst prepared from Feitknecht compound. Tubular carbon nanotubes, bamboo-shaped carbon naotubes, herringbone carbon nanotubues and branched carbon nanotubes are all found formed at moderate temperature. It is important for the formation of quasi-liquid state of the metal nanoparticles at the tip of carbon naotubes during the growth of carbon nanotubes to lead to different kinds of carbon nanotubes. It is likely that the addition of zinc make the activity of nickel catalyst after calcinations and reduction changed strangely.     

氮化SBA-16负载镍基催化剂的制备及其对甲烷二氧化碳重整反应的催化性能

通过软模板法合成了SBA-16分子筛,采用高温氨气氮化的方法使有序介孔硅材料中的氧原子部分被氮原子取代,得到氮化的SBA-16载体(SBA-16-N)。采用满孔浸渍法制备了镍基催化剂,并将制得的Ni/SBA-16和Ni/SBA-16-N催化剂用于甲烷二氧化碳重整反应。通过透射电镜、氮气物理吸附、X射线衍射、X射线光电子能谱和二氧化碳程序升温脱附等手段研究了载体和催化剂的结构,并利用热重分析对反应之后回收催化剂进行了表征。结果表明,高温氮化后的分子筛中掺入了氮元素,增加了载体的碱性,改善了载体对反应气体的吸附活化能力,增强了载体与金属之间的相互作用,从而提高了催化剂的活性和抗积炭性能。     

石墨烯负载镍催化CO_2加氢甲烷化

采用改进的Hummers法制备了氧化石墨烯(GO),经水合肼还原得到石墨烯(RGO),通过浸渍法制备了石墨烯负载的镍基催化剂(Ni/RGO);对其催化二氧化碳甲烷化反应的性能进行了研究,并与以碳纳米管(CNTs)和活性炭(AC)为载体负载的Ni基催化剂进行了比较.由于催化剂的载体分别为RGO,CNTs和AC,所以Ni将会表现出不同的形态.利用红外光谱(FTIR)、比表面积(BET)测试、程序升温还原(H2-TPR)、X射线衍射(XRD)分析和透射电子显微镜(TEM)等表征手段对其结构及物理性质进行了表征.结果表明,Ni/RGO具有相对较大的比表面积(316 m~2/g),Ni在Ni/RGO上的颗粒尺寸(5.3 nm)小于其在Ni/CNTs(8.9 nm)和Ni/AC(11.6 nm)上的颗粒尺寸;该催化剂在二氧化碳甲烷化反应中具有更高的催化活性和选择性,而且具有良好的使用寿命.     

La~2NiO~4催化制备纳米碳管

制备了四方结构复合氧化物La~2NiO~4,并以其为催化剂前体,甲烷和一氧化碳为碳,合成出大量高纯度的纳米碳管。XRD结果表明La~2NiO~4经还原后,在La~2O~3的隔离作用下Ni晶粒实现纳米级均匀分散。利用TEM,HRTEM,SEM,XRD,Raman等手段对所制备的纳米碳管进行了观察和表征。所制备的纳米碳管管径均匀、石墨化程度较高,该法制备纳米碳管工艺简单、产量较高,产品易于纯化。     

Catalytic performances of Ni/mesoporous SiO_2 catalysts for dry reforming of methane to hydrogen

Several mesoporous silicas with different morphologies were controllably prepared by sol-gel method with adjustable ratio of dual template,and they were further impregnated with aqueous solution of nickel nitrate,followed by calcination in air.The synthesized silica supports and supported nickel samples were characterized using N_2-adsorption/desorption,X-ray diffraction(XRD),H_2 temperature-programmed reduction(H_2-TPR),Scanning electron microscope(SEM),Transmission electron microscope(TEM) and thermo-gravimetric analysis(TGA-DTG) techniques.The Ni nanoparticles supported on shell-like silica are highly dispersed and yielded much narrower nickel particle-size than those on other mesoporous silica.The methane reforming with dioxide carbon reaction results showed that Ni nanoparticles supported on shell-like silica carrier exhibited the better catalytic performance and catalytic stability than those of nickel catalyst supported on other silica carrier.The thermo-gravimetric analysis on used nickel catalysts uncovered that catalyst deactivation depends on the type and nature of the coke deposited.The heterogeneous nature of the deposited coke was observed on nickel nanoparticles supported on spherical and peanut-like silica.Much narrower and lower TGA derivative peak was founded on Ni catalyst supported on the shell-like silica.     

Electrodeposition of platinum–nickel alloy nanocomposites on polyaniline-multiwalled carbon nanotubes for carbon monoxide redox

An electrochemical method was developed to deposit platinum (Pt)–nickel (Ni) alloy nanocomposites on polyaniline-multiwalled carbon nanotubes (Pt–Ni/PAN/MWCNTs). The material was characterized by various methods including field emission scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical techniques. An appreciably improved catalysis toward oxidation of carbon monoxide (CO) was observed at the Pt–Ni/PAN/MWCNTs nanocomposites (real ratio of Pt–Ni of 17:1), which was interpreted by a mechanism based on the bifunctional catalysis. The successful preparation of Pt–Ni/PAN/MWCNTs nanocomposites opens a new path to synthesize the promising catalysts for CO.     

Nickel catalysts supported on MgO with different specific surface area for carbon dioxide reforming of methane

In this paper, three kinds of MgO with different specific surface area were prepared, and their effects on the catalytic performance of nickel catalysts for the carbon dioxide reforming of methane were investigated. The results showed that MgO support with the higher specific surface area led to the higher dispersion of the active metal, which resulted in the higher initial activity. On the other hand, the specific surface area of MgO materials might not be the dominant factor for the basicity of support to chemisorb and activate CO₂, which was another important factor for the performance of catalysts. Herein, Ni/MgO(CA) catalyst with proper specific surface area and strong ability to activate CO₂ exhibited stable catalytic property and the carbon species deposited on the Ni/MgO(CA) catalyst after 10 h of reaction at 650 °C were mainly activated carbon species.     

纳米碳管负载金属镍催化叶绿素加氢反应

用等体积浸渍法制备了纳米碳管负载金属镍催化剂，采用电镜(TEM）、红外光谱（IR）对催化剂的形貌、结构进行了表征.并考察了常温常压下不同Ni负载量的催化剂对叶绿素加氢反应的性能.结果表明，纳米碳管负载镍催化剂在催化反应过程中保持高分散态，不会发生团聚.而经过硝酸氧化后的纳米碳管负载镍催化剂在催化反应中表现出高的活性.当Ni负载量为7％时，催化活性最好，叶绿素分子开环生成各种小分子.     

Preparation and characterization of nanoporous carbon supports on a nickel/sibunit catalyst

A nanoporous composite carbon material was developed; this material was prepared by the synthesis of catalytic filamentous carbon (CFC) on a Ni catalyst supported onto the Sibunit carbon support. The texture characteristics (specific surface area and pore structure) of this material were studied. The effects of the conditions of supporting bivalent nickel compounds from aqueous or water-ethanol solutions in the presence of urea and the pretreatment of the parent Sibunit (oxidation and reduction) on the yield of synthesized carbon were considered. The distribution of Ni inside a Sibunit granule was studied using energy dispersive X-ray microanalysis. The surface morphology of the Ni/Sibunit catalyst, as well as the synthesized carbon layer, was studied by scanning electron microscopy. It was found that a maximum yield of carbon (50–60 g/(g Ni)) was obtained on the precipitation of nickel compounds from water-ethanol solutions with an ethanol concentration of 5 to 50 vol %. The preliminary surface oxidation or reduction of the parent Sibunit resulted in a considerable decrease in the yield of carbon (by a factor of 2 or more). The parent Sibunit phase occurred within the prepared nanoporous carbon material, whereas a shell formed by CFC occurred on the outside.     

Olivary particles: unique carbon microstructure synthesized by catalytic pyrolysis of acetone

Olivary (olive-shaped) carbon particles (OCPs) with a diameter of approximately 1.5-2 mum at the middle and a length of approximately 3-4 mum were synthesized by pyrolysis of acetone with metallic zinc as the catalyst at 600 degrees C. The content of the OCPs in the product is related to the catalyst, the pyrolysis temperature, and the time of ultrasonic dispersion before pyrolysis. The content of the OCPs was over 90% of the product under the optimum condition. Mg, Ni, Fe, Cu, Zn, and Cd powder were used as catalysts in the experiments, respectively, in which the metallic zinc powder was outstanding in the pyrolyzing process; the metallic iron and cadmium powder also improved the formation of the olivary carbon particles; however, magnesium, nickel, and copper could not operate the catalysis. Through Fourier transform infrared spectroscopy analysis, the mechanism of the formation of the olivary carbon particles was suggested to be an indirectly catalytic and self-assemble process. By high-resolution transmission electron microscope observation, an interesting arrangement of crystal planes of carbon was found that (002) planes of graphite near the surface are vertical to the surface of the OCPs and not parallel as usual.