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过刊目录

    催化学报
    Chinese Journal of Catalysis

    2014, Vol. 35, No. 6
    Online: 2014-05-30

    封面介绍:

    吴树昌等研究发现, 水合肼还原硝基苯可以在碳材料催化作用下发生, 碳表面的含氧基团, 而不是比表面积、孔结构、形貌、结构缺陷以及铁杂质对反应活性有重大影响. 在各种官能团中, 羰基的作用非常重要, 而羧基和酸酐对反应不利. 反应通过直接途径进行, 中间体亚硝基苯可直接转化为苯胺. 见本期第 914–921 页.

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    目录
    第35卷第6期目次
    2014, 35 (6):  0-0. 
    摘要 ( 143 )   PDF(1773KB) ( 505 )  
    编者语
    Preface to Special Issue on Carbon in Catalysis
    Dr. Dangsheng Su
    2014, 35 (6):  777-777.  DOI: 10.1016/S1872-2067(14)60142-X
    摘要 ( 175 )   [Full Text(HTML)] () PDF(199KB) ( 374 )  
    散文
    Classification of carbon materials for developing structure-properties relationships based on the aggregate state of the precursors
    Oleksiy V. Khavryuchenko, Volodymyr D. Khavryuchenko
    2014, 35 (6):  778-782.  DOI: 10.1016/S1872-2067(14)60112-1
    摘要 ( 275 )   [Full Text(HTML)] () PDF(481KB) ( 812 )  

    Modern carbon science lacks an efficient structure-related classi-fication of materials. We present an approach based on dividing carbon materials by the aggregate state of the precursor. The common features in the structure of carbon particles that allow putting them into a group are discussed, with particular attention to the potential energy stored in the carbon structure from differ-ent rates of relaxation during the synthesis and prearrangement of structural motifs due to the effect of the precursor structure.

    研究视角
    Carbon-based catalysts:Opening new scenario to develop next-generation nano-engineered catalytic materials
    Claudio Ampelli, Siglinda Perathoner, Gabriele Centi
    2014, 35 (6):  783-791.  DOI: 10.1016/S1872-2067(14)60139-X
    摘要 ( 296 )   [Full Text(HTML)] () PDF(859KB) ( 851 )  

    This essay analyses some of the recent development in nanocarbons (carbon materials having a defined and controlled nano-scale dimension and functional properties which strongly depend on their nano-scale features and architecture), with reference to their use as advanced catalytic materials. It is remarked how their features open new possibilities for catalysis and that they represent a new class of catalytic materials. Although carbon is used from long time in catalysis as support and electrocatalytic applications, nanocarbons offer unconventional ways for their utilization and to address some of the new challenges deriving from moving to a more sustainable future. This essay comments how nanocarbons are a key element to develop next-generation catalytic materials, but remarking that this goal requires overcoming some of the actual limits in current research. Some aspects are discussed to give a glimpse on new directions and needs for R&D to progress in this direction.

    小综述
    Catalysis:An old but new challenge for graphene-based materials
    Ljubisa R. Radovic, Camila Mora-Vilches, Adolfo J. A. Salgado-Casanova
    2014, 35 (6):  792-797.  DOI: 10.1016/S1872-2067(14)60130-3
    摘要 ( 348 )   [Full Text(HTML)] () PDF(362KB) ( 544 )  

    An assessment is offered regarding the progress made, and the remaining challenges, in the field of carbocatalysis. The fundamental principles that govern the preparation and performance of sp2-hybridized carbon materials in heterogeneous catalysis have been known for decades, and the level of understanding of key issues-especially the importance of textural and ion-exchange properties (i.e., surface area, pore size distribution, and proton transfer)-remains quite satisfactory. The opportunities for novel catalytic materials-especially graphene nanosheets and carbon nanotubes-are tremendous, especially when it comes to taking advantage of their structural order, such that electron transfer can be both better understood and controlled to enhance catalytic activity and selectivity.

    Carbon nanohybrids used as catalysts and emulsifiers for reactions in biphasic aqueous/organic systems
    Daniel E. Resasco
    2014, 35 (6):  798-806.  DOI: 10.1016/S1872-2067(14)60119-4
    摘要 ( 275 )   [Full Text(HTML)] () PDF(894KB) ( 562 )  

    This mini-review summarizes some novel aspects of reactions conducted in aqueous/organic emulsions stabilized by carbon nanohybrids functionalized with catalytic species. Carbon nanohybrids represent a family of solid catalysts that not only can stabilize water-oil emulsions in the same fashion as Pickering emulsions, but also catalyze reactions at the liquid/liquid interface. Several examples are discussed in this mini-review. They include (a) aldol condensation-hydrodeoxygenation tandem reactions catalyzed by basic (MgO) and metal (Pd) catalysts, respectively; (b) Fischer-Tropsch synthesis catalyzed by carbon-nanotube-supported Ru; and (c) emulsion polymerization of styrene for the production of conductive polymer composites. Conducting these reactions in emulsion generates important advantages, such as increased liquid/liquid interfacial area that consequently means faster mass transfer rates of molecules between the two phases, effective separation of products from the reaction mixture by differences in the water-oil solubility, and significant changes in product selectivity that can be adjusted by modifying the emulsion characteristics.

    On the photoactivity of S-doped nanoporous carbons:Importance of surface chemistry and porosity
    Teresa J. Bandosz, Mykola Seredych
    2014, 35 (6):  807-814.  DOI: 10.1016/S1872-2067(14)60100-5
    摘要 ( 245 )   [Full Text(HTML)] () PDF(1181KB) ( 387 )  

    This minireview summarizes our recent findings on the photoactivity of S-doped nanoporous carbons. The materials were either synthesized from the sulfur-containing polymers or obtained by heat treatment of commercial carbon with hydrogen sulfide. Their surface was extensively characterized from the points of view of its surface chemistry, porosity, morphology, and electronic properties. The carbons showed enhanced activity towards oxidation of arsine and removal of dibenzothiophenes from model diesel fuel. The latter were oxidized to various oxygen containing intermediates and the cleavage of C-C bonds in aromatic ring was detected when carbon with adsorbed species was exposed to UV or visible light. Irradiation resulted in generation of photocurrent in a broad range of wavelength. The presence of sulfur led to the reduction of oxygen and contributed to an increased capacitive performance. We link these effects to the presence of reduced sulfur in the small pores which enhances the dispersive interactions via inducing a positive charge to carbon atoms, to sulfur in oxygenated forms which contribute to Faradaic reactions and increase the polar interactions, and to the hydrophobicity of a surface in small pores where oxygen can be reduced by excited electrons from chromophoric-like sulfur containing groups.

    综述
    Proton catalysis with active carbons and partially pyrolyzed carbonaceous materials
    V. V. Strelko, S. S. Stavitskaya, Yu. I. Gorlov
    2014, 35 (6):  815-823.  DOI: 10.1016/S1872-2067(14)60147-9
    摘要 ( 226 )   [Full Text(HTML)] () PDF(501KB) ( 619 )  

    The development of environmentally friendly solid acid catalysts is a priority task. Highly oxidized activated carbon and their ion-substituted (saline) forms are effective proton transfer catalysts in esterification, hydrolysis, and dehydration, and thus are promising candidates as solid acid catalysts. Computations by the ab initio method indicated the cause for the enchanced acidity of the carboxylic groups attached to the surface of highly oxidized carbon. The synthesis of phosphorilated carbon was considered, and the proton transfer reactions catalyzed by them in recent studies were analyzed. The development of an amorphous carbon acid catalyst comprising polycyclic carbonaceous (graphene) sheets with-SO3H,-COOH and phenolic type OH-groups was carried out. These new catalysts were synthesized by partial pyrolysis and subsequent sulfonation of carbohydrates, polymers, and other organic compounds. Their high catalytic activities in proton transfere reactions including the processing of bio-based raw materials was demonsrated.

    Carbon mediated catalysis:A review on oxidative dehydrogenation
    De Chen, Anders Holmen, Zhijun Sui, Xinggui Zhou
    2014, 35 (6):  824-841.  DOI: 10.1016/S1872-2067(14)60120-0
    摘要 ( 364 )   [Full Text(HTML)] () PDF(1027KB) ( 1084 )  

    Carbon mediated catalysis has gained an increasing attention in both areas of nanocatalysis and nanomaterials. The progress in carbon nanomaterials provides many new opportunities to manipulate the types and properties of active sites of catalysts through manipulating structures, functionalities and properties of carbon surfaces. The present review focuses on progresses in carbon mediated oxidative dehydrogenation reactions of ethylbenzene, propane, and butane. The state-of-the- art of the developments of carbon mediated catalysis is discussed in terms of fundamental studies on adsorption of oxygen and hydrocarbons, reaction mechanism as well as effects of carbon nanomaterial structures and surface functional groups on the catalytic performance. We highlight the importance and challenges in tuning of the electron density of carbon and oxygen on carbon surfaces for improving selectivity in oxidative dehydrogenation reactions.

    Functional carbons and carbon nanohybrids for the catalytic conversion of biomass to renewable chemicals in the condensed phase
    John Matthiesen, Thomas Hoff, Chi Liu, Charles Pueschel, Radhika Rao, Jean-Philippe Tessonnier
    2014, 35 (6):  842-855.  DOI: 10.1016/S1872-2067(14)60122-4
    摘要 ( 333 )   [Full Text(HTML)] () PDF(1180KB) ( 756 )  

    The production of chemicals from lignocellulosic biomass provides opportunities to synthesize chemicals with new functionalities and grow a more sustainable chemical industry. However, new challenges emerge as research transitions from petrochemistry to biorenewable chemistry. Compared to petrochemisty, the selective conversion of biomass-derived carbohydrates requires most catalytic reactions to take place at low temperatures (< 300℃) and in the condensed phase to prevent reactants and products from degrading. The stability of heterogeneous catalysts in liquid water above the normal boiling point represents one of the major challenges to overcome. Herein, we review some of the latest advances in the field with an emphasis on the role of carbon materials and carbon nanohybrids in addressing this challenge.

    研究论文
    Comparing characterization of functionalized multi-walled carbon nanotubes by potentiometric proton titration, NEXAFS, and XPS
    Zhiteng Zhang, Lisa Pfefferle, Gary L. Haller
    2014, 35 (6):  856-863.  DOI: 10.1016/S1872-2067(14)60123-6
    摘要 ( 304 )   [Full Text(HTML)] () PDF(435KB) ( 738 )  

    Since the discovery of carbon nanotubes (CNT), this material has been recognized as an attractive catalyst support. CNT must be functionalized before use as a catalyst support and typically this involves oxidation. However, the functional group distribution on the CNT is very complex mixture of groups and varies with oxidation agent used. Here a simple acid-base titration is introduced to characterize the oxygen functionalized CNT. By comparing characterization with near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) for both at the C and O K-edges, it can be demonstrated that potentiometric proton titration can be a fast and quantitative analysis for Brönsted acid functional groups on CNT.

    A selective way to create defects by the thermal treatment of fluorinated double walled carbon nanotubes
    Hiroyuki Muramatsu, Kazunori Fujisawa, Yong-Il Ko, Kap-Seung Yang, Takuya Hayashi, Morinobu Endo, Cheol-Min Yang, Yong Chae Jung, Yoong Ahm Kim
    2014, 35 (6):  864-868.  DOI: 10.1016/S1872-2067(14)60107-8
    摘要 ( 222 )   [Full Text(HTML)] () PDF(1404KB) ( 569 )  

    Nanoscale defects in the outer tube to preserve the electrical and optical features of the inner tube can be engineered to exploit the intrinsic properties of double walled carbon nanotubes (DWCNTs) for various promising applications. We demonstrated a selective way to make defects in the outer tube by the fluorination of DWCNTs followed by the thermal detachment of the F atoms at 1000℃ in argon. Fluorinated DWCNTs with different amounts of F atoms were prepared by reacting with fluorine gas at 25, 200, and 400℃ that gave the stoichiometry of CF0.20, CF0.30, and CF0.43, respectively. At the three different temperatures used, we observed preservation of the coaxial morphology in the fluorinated DWCNTs. For the DWCNTs fluorinated at 25 and 200℃, the strong radial breathing modes (RBMs) of the inner tube and weakened RBMs of the outer tube indicated selective fluorine attachment onto the outer tube. However, the disappearance of the RBMs in the Raman spectrum of the DWCNTs fluorinated at 400℃ showed the introduction of F atoms onto both inner and outer tubes. There was no significant change in the morphology and optical properties when the DWCNTs fluorinated at 25 and 200℃ were thermally treated at 1000℃ in argon. However, in the case of the DWCNTs fluorinated at 400℃, the recovery of strong RBMs from the inner tube and weakened RBMs from the outer tube indicated the selective introduction of substantial defects on the outer tube while preserving the original tubular shape. The thermal detachment of F atoms from fluorinated DWCNTs is an efficient way to make highly defective outer tubes for preserving the electrical conduction and optical activity of the inner tubes.

    Low-temperature graphitization of amorphous carbon nanospheres
    Katia Barbera, Leone Frusteri, Giuseppe Italiano, Lorenzo Spadaro, Francesco Frusteri, Siglinda Perathoner, Gabriele Centi
    2014, 35 (6):  869-876.  DOI: 10.1016/S1872-2067(14)60098-X
    摘要 ( 353 )   [Full Text(HTML)] () PDF(1049KB) ( 927 )  

    The investigation by SEM/TEM, porosity, and X-ray diffraction measurements of the graphitization process starting from amorphous carbon nanospheres, prepared by glucose carbonization, is reported. Aspects studied are the annealing temperature in the 750-1000℃ range, the type of inert carrier gas, and time of treatment in the 2-6 h range. It is investigated how these parameters influence the structural and morphological characteristics of the carbon materials obtained as well as their nanostructure. It is shown that it is possible to maintain after graphitization the round-shaped macro morphology, a high surface area and porosity, and especially a large structural disorder in the graphitic layers stacking, with the presence of rather small ordered domains. These are characteristics interesting for various catalytic applications. The key in obtaining these characteristics is the thermal treatment in a flow of N2. It was demonstrated that the use of He rather than N2 does not allow obtaining the same results. The effect is attributed to the presence of traces of oxygen, enough to create the presence of oxygen functional groups on the surface temperatures higher than 750℃, when graphitization occurs. These oxygen functional groups favor the graphitization process.

    以细菌纤维素为前驱体简便制备氮掺杂碳纤维气凝胶作为高效氧还原催化剂
    孟凡陆, 李霖, 吴中, 钟海霞, 李建忱, 鄢俊敏
    2014, 35 (6):  877-883.  DOI: 10.1016/S1872-2067(14)60126-1
    摘要 ( 301 )   [Full Text(HTML)] () PDF(1440KB) ( 815 )  

    数十年来,碳气凝胶因其在催化剂载体、电容器和锂电池电极材料以及吸附剂等领域的潜在应用而备受关注.然而,传统碳气凝胶的制备往往使用昂贵且有毒的前驱体,其方法也较为复杂,不利于大规模生产及应用.本文介绍了一种以细菌纤维素为前驱体制备氮掺杂碳纤维气凝胶的方法.该方法廉价高效,简单易行且对环境无害.所制气凝胶具有密度低、孔隙度高、比表面积大以及导电性良好等优点.它继承了细菌纤维素生物质优异的三维交联多孔结构的特点,可直接用作氧还原催化剂,表现出优异的催化性能,预示着其广泛的应用前景.这在该领域的应用报道尚属首次.

    Solution phase synthesis of halogenated graphene and the electrocatalytic activity for oxygen reduction reaction
    Kuang-Hsu Wu, Da-Wei Wang, Qingcong Zeng, Yang Li, Ian R. Gentle
    2014, 35 (6):  884-890.  DOI: 10.1016/S1872-2067(14)60108-X
    摘要 ( 294 )   [Full Text(HTML)] () PDF(913KB) ( 569 )  

    Metal-free carbon electrocatalyts for the oxygen reduction reaction (ORR) are attractive for their high activity and economic advantages. However, the origin of the activity has never been clearly elucidated in a systematic manner. Halogen group elements are good candidates for elucidating the effect, although it has been a difficult task due to safety issues. In this report, we demonstrate the synthesis of Cl-, Br-and I-doped reduced graphene oxide through two solution phase syntheses. We have evaluated the effectiveness of doping and performed electrochemical measurements of the ORR activity on these halogenated graphene materials. Our results suggest that the high electronegativity of the dopant is not the key factor for high ORR activity; both Br-and I-doped graphene promoted ORR more efficiently than Cl-doped graphene. Furthermore, an unexpected sulfur-doping in acidic conditions suggests that a high level of sulfide can degrade the ORR activity of the graphene material.

    Electrocatalytic oxygen evolution reaction at a FeNi composite on a carbon nanofiber matrix in alkaline media
    Xianghua An, Dongyoon Shin, Joey D. Ocon, Jae Kwang Lee, Young-il Son, Jaeyoung Lee
    2014, 35 (6):  891-895.  DOI: 10.1016/S1872-2067(14)60127-3
    摘要 ( 384 )   [Full Text(HTML)] () PDF(466KB) ( 714 )  

    Non-noble metals such as Fe and Ni have comparable electrocatalytic activity and stability to that of Ir and Ru in an oxygen evolution reaction (OER). In this study, we synthesized carbon nanofibers with embedded FeNi composites (FeNi-CNFs) as OER electrocatalysts by a facile route comprising electrospinning and the pyrolysis of a mixture of metal precursors and a polymer solution. FeNi-CNFs demonstrated catalytic activity and stability that were better than that of 20 wt% Ir on Vulcan carbon black in oxidizing water to produce oxygen in an alkaline media. Physicochemical and electrochemical characterization revealed that Fe and Ni had synergistic roles that enhanced OER activity by the uniform formation and widening of pores in the carbon structure, while the CNF matrix also contributed to the increased stability of the catalyst.

    Catalytic performance of heteroatom-modified carbon nanotubes in advanced oxidation processes
    João Restivo, Raquel P. Rocha, Adrián M. T. Silva, José J. M. Órfão, Manuel F. R. Pereira, José L. Figueiredo
    2014, 35 (6):  896-905.  DOI: 10.1016/S1872-2067(14)60103-0
    摘要 ( 223 )   [Full Text(HTML)] () PDF(539KB) ( 632 )  

    Multi-walled carbon nanotubes (CNTs) were submitted to chemical and thermal treatments in order to incorporate different heteroatoms on the surface. O-, S-and N-containing groups were successfully introduced onto the CNTs without significant changes of the textural properties. The catalytic activity of these heteroatom-modified CNTs was studied in two liquid phase oxidation processes: catalytic ozonation and catalytic wet air oxidation (CWAO), using oxalic acid and phenol as model compounds. In both cases, the presence of strongly acidic O-containing groups was found to decrease the catalytic activity of the CNTs. On the other hand, the introduction of S species (mainly sulfonic acids) enhanced the removal rate of the model compounds, particularly in the CWAO of phenol. Additional experiments were performed with a radical scavenger and sodium persulfate, in order to clarify the reaction mechanism. Nitrogen functionalities improve the catalytic performance of the original CNTs, regardless of the process or of the pollutant.

    Nitrogen-doped carbon nanotubes on silicon carbide as a metal-free catalyst
    Cuong Duong-Viet, Housseinou Ba, Yuefeng Liu, Lai Truong-Phuoc, Jean-Mario Nhut, Cuong Pham-Huu
    2014, 35 (6):  906-913.  DOI: 10.1016/S1872-2067(14)60116-9
    摘要 ( 269 )   [Full Text(HTML)] () PDF(886KB) ( 850 )  

    A hierarchical metal-free catalyst consisting of nitrogen-doped carbon nanotubes decorated onto a silicon carbide (N-CNTs/SiC) macroscopic host structure was prepared. The influence of N-CNTs incorporation on the physical properties of the support was evaluated using different characterization techniques. The catalyst was tested as a metal-free catalyst in the selective oxidation of H2S and steam-free dehydrogenation of ethylbenzene. The N-CNTs/SiC catalyst exhibited extremely good desulfurization performance compared to a Fe2O3/SiC catalyst under less conducive reaction conditions such as low temperature, high space velocity, and a low O2-to-H2S molar ratio. For the dehydrogenation of ethylbenzene, a higher dehydrogenation activity was obtained with the N-CNTs/SiC catalyst compared to a commercial K-Fe/Al2O3 catalyst. The N-CNTs/SiC catalyst also displayed good stability as a function of time on stream for both reactions, which was attributed to the strong anchoring of the nitrogen dopant in the carbon matrix. The extrudate shape of the SiC support allowed the direct macroscopic shaping of the catalyst for use in a conventional fixed-bed reactor without the problems of catalyst handling, transportation, and pressure drop across the catalyst bed that are encountered with nanoscopic carbon-based catalysts.

    碳材料催化硝基苯还原反应
    吴树昌, 温国栋, 钟炳伟, 张炳森, 谷献模, 王宁, 苏党生
    2014, 35 (6):  914-921.  DOI: 10.1016/S1872-2067(14)60102-9
    摘要 ( 268 )   [Full Text(HTML)] () PDF(775KB) ( 863 )  

    本文对碳材料(主要是碳纳米管)催化硝基苯的还原反应进行了系统研究.通过热重分析、程序升温脱附、透射电子显微镜、物理吸附以及拉曼光谱等表征,发现碳材料表面的含氧官能团在反应中起着重要的作用,而比表面、孔结构、形貌、结构缺陷以及可能存在的铁杂质对反应没有显著影响.羰基的作用非常重要,但是羧基和酸酐对反应不利.除此之外,材料的π电子体系也很关键,因为它可以传递电子,并且利于硝基苯的吸附.硝基苯还原按照直接路径进行,反应过程中生成的中间体亚硝基苯可以迅速转化为苯胺.

    氮掺杂石墨烯的生长机理及其在乙苯选择性氧化中的应用
    唐沛, 高勇军, 杨敬贺, 李文静, 赵华博, 马丁
    2014, 35 (6):  922-928.  DOI: 10.1016/S1872-2067(14)60150-9
    摘要 ( 258 )   [Full Text(HTML)] () PDF(777KB) ( 598 )  

    以热解氧化石墨烯材料为碳基底,分别使用有机氮源和无机氮源对其进行氮掺杂处理,制备了一系列氮掺杂石墨烯材料.采用透射电子显微镜、扫描电子显微镜、拉曼光谱和X射线光电子能谱等表征方法考察了氮掺杂石墨烯的生长机理.结果表明,随着制备过程中退火温度的改变,氮掺杂石墨烯中不同氮物种的含量有显著差别.这种差异是由不同氮物种化学环境的差异所导致的.所制备的含氮石墨烯材料对乙苯选择性氧化制苯乙酮反应均表现出优良的催化活性.其中,石墨氮的含量对于提高苯乙酮收率起到至关重要的作用.此外,通过氧化剂控制活化的方法可以消除过多的结构缺陷和过量氮掺杂对催化反应的不利影响,有效提升氮掺杂石墨烯的催化活性.

    Esterification of levulinic acid into ethyl levulinate catalysed by sulfonated hydrothermal carbons
    Filoklis D. Pileidis, Maham Tabassum, Sam Coutts, Maria-Magdalena Titirici
    2014, 35 (6):  929-936.  DOI: 10.1016/S1872-2067(14)60125-X
    摘要 ( 397 )   [Full Text(HTML)] () PDF(764KB) ( 1434 )  

    The synthesis of carbon-based, heterogeneous sulphonic catalysts for the production of levulinate esters. Hydrothermal treatment at moderated temperatures was employed to generate highly functional carbonaceous materials, referred to as hydrothermal carbons (HTCs), from both glucose, cellulose and rye straw. The products were sulfonated to generate solid acid-catalysts. Characterisation of the as-synthesised materials as well as catalyst activity tests were performed. SEM images indicate the micrometre-sized particles present in both HTCs were largely unaffected by sulfonation, although cellulose-derived HTC displayed signs of inadequate hydrolysis. FT-IR spectroscopy and elemental analysis confirmed successful incorporation of sulphonic groups. 13C solid state NMR, in addition to TGA, elucidated the carbons' structural composition and supported the commonly-proposed hydrothermal carbonisation mechanism. Finally, the catalysts were tested via levulinic acid-ethanol esterification and gave high conversion and ester-selectivities (> 90%).

    碱性条件下Ru/C催化5-羟甲基糠醛选择氧化反应
    解佳翰, 聂俊芳, 刘海超
    2014, 35 (6):  937-944.  DOI: 10.1016/S1872-2067(14)60136-4
    摘要 ( 383 )   [Full Text(HTML)] () PDF(652KB) ( 1023 )  

    以活性炭负载金属钌(Ru/C)为催化剂,在碱性水溶液中研究了5-羟甲基糠醛(HMF)选择氧化反应.与MgO,Ca(OH)2和NaOH相比,加入具有合适碱强度的镁铝水滑石有利于生成5-甲酰基-2-呋喃甲酸(FFCA)或2,5-呋喃二甲酸(FDCA).X射线光电子能谱实验表明金属态的钌是活性催化中心.同位素示踪结果则表明水而非氧气提供了5-甲酰基-2-呋喃甲酸及2,5-呋喃二甲酸等羧酸产物的氧源.根据这些结果,并结合HMF和2,5-呋喃二甲醛氧化的动力学研究,我们提出HMF选择性氧化制备FFCA遵循Langmuir-Hinshelwood反应机理.其中,HMF在金属Ru表面饱和解离吸附,在解离吸附的氧原子的协助下发生β-脱氢生成2,5-呋喃二甲醛(DFF)吸附物种.该DFF物种进一步发生水合与氧化形成FFCA产物.

    Fragrances by selective oxidation of long-chain alcohols
    Alberto Villa, Carine E-Chan-Thaw, Marco Schiavoni, Sebastiano Campisi, Di Wang, Laura Prati
    2014, 35 (6):  945-951.  DOI: 10.1016/S1872-2067(14)60101-7
    摘要 ( 229 )   [Full Text(HTML)] () PDF(403KB) ( 607 )  

    The activity and the selectivity of Ru and Pt based carbon catalysts in the selective oxidation of long-chain aliphatic alcohols (C8, C10, C12) have been investigated. Ru/AC and Pt/AC always showed good initial activity, however deactivation phenomena rapidly depressed the catalytic performance of the catalysts. These phenomena can be limited by modification of Ru/AC and Pt/AC with Au improving the durability of the catalyst. Ru/AC and AuRu/AC showed good selectivity to the corresponding aldehyde (>95%) making these catalysts promising for fragrances manufacturing. The advantage in using Au modified catalyst lies on the easier regeneration procedure compared to the one necessary for Ru/AC. Pt /AC and AuPt/AC showed a lower selectivity to aldehyde promoting the formation of the acid and the ester formation respectively. The addition of water in the solvent system speeds up the reaction rate but drastically decreased the selectivity to aldehyde especially in the case of Pt based catalysts.

    石墨烯负载的金属氧化物纳米颗粒的可控制备及催化性能
    伍颖斯, 余皓, 王红娟, 彭峰
    2014, 35 (6):  952-959.  DOI: 10.1016/S1872-2067(14)60114-5
    摘要 ( 365 )   [Full Text(HTML)] () PDF(1632KB) ( 922 )  

    采用直接浸渍法、过氧化氢均相氧化沉积法和氨水催化水解法制备了石墨烯负载的铁、钴、镍金属氧化物纳米颗粒.研究了三种沉积方法对颗粒尺寸分布的影响;采用透射电子显微镜、傅里叶变换红外光谱、X射线衍射和X射线光电子能谱表征了催化剂的形貌与结构.用过氧化氢均相氧化沉淀法可制得粒径分布最均匀的纳米颗粒.过氧化氢的氧化作用可使石墨烯表面的氧化基团含量最大化,为纳米颗粒提供了足够的吸附与成核点.氨水加速了金属离子的水解与成核,导致纳米颗粒的粒径增大与不均.以苯甲醇氧化为探针反应考察了催化剂的性能.催化剂的活性按以下顺序逐渐下降:过氧化氢辅助沉积法>直接浸渍法>氨水催化水解法,与纳米颗粒尺寸增长趋势一致.纳米催化剂颗粒尺寸与其活性的良好关联性显示,发展石墨烯负载尺寸可控的纳米催化剂的方法具有重要意义.

    Catalytic and capacity properties of nanocomposites based on cobalt oxide and nitrogen-doped carbon nanofibers
    Olga Yu. Podyacheva, Andrei I. Stadnichenko, Svetlana A. Yashnik, Olga A. Stonkus, Elena M. Slavinskaya, Andrei I. Boronin, Andrei V. Puzynin, Zinfer R. Ismagilov
    2014, 35 (6):  960-969.  DOI: 10.1016/S1872-2067(14)60099-1
    摘要 ( 261 )   [Full Text(HTML)] () PDF(755KB) ( 496 )  

    The nanocomposites based on cobalt oxide and nitrogen-doped carbon nanofibers (N-CNFs) with cobalt oxide contents of 10-90 wt% were examined as catalysts in the CO oxidation and supercapacity electrodes. Depending on Co3O4 content, such nanocomposites have different morphologies of cobalt oxide nanoparticles, distributions over the bulk, and ratios of Co3+/Co2+ cations. The 90%Co3O4-N-CNFs nanocomposite showed the best activity because of the increased concentration of defects in N-CNFs. The capacitance of electrodes containing 10%Co3O4-N-CNFs was 95 F/g, which is 1.7 times higher than electrodes made from N-CNFs.

    Conversion of isopropyl alcohol over Ru and Pd loaded N-doped carbon nanotubes
    Anas Benyounes, Mohamed Kacimi, Mahfoud Ziyad, Philippe Serp
    2014, 35 (6):  970-978.  DOI: 10.1016/S1872-2067(14)60121-2
    摘要 ( 273 )   [Full Text(HTML)] () PDF(1856KB) ( 2021 )  

    Ru and Pd (2 wt%) loaded on pure and on N-doped carbon nanotubes (N-CNTs) were prepared and tested using the isopropyl alcohol decomposition reaction as probe reaction. The presence of nitrogen functionalities (pyridinic, pyrrolic, and quaternary nitrogen) on the nitrogen doped support induced a higher metal dispersion: Pd/N-CNT (1.8 nm) < Pd/CNT (4.9 nm), and Ru/N-CNT (2.4 nm) < Ru/CNT (3.0 nm). The catalytic activity of the supports was determined first. Isopropyl alcohol conversion produces acetone on CNTs while on N-CNTs it led to both dehydration and dehydrogenation products. At 210℃ and in the presence of air, the isopropyl alcohol conversion was higher on the N-CNTs (25%) than on the CNTs (11%). The Pd loaded catalysts were more active and more selective than the Ru ones. At 115℃, the Pd catalysts were 100% selective towards acetone for a conversion of 100%, whereas the Ru catalysts led to dehydration and dehydrogenation products. The nitrogen doping induced the appearance of redox properties when oxygen is present in the reaction mixture.

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    2014, 35 (6):  979-980. 
    摘要 ( 216 )   [Full Text(HTML)] () PDF(247KB) ( 269 )