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  • Vanadium−Doped Porous Silica Materials with High Catalytic Activity and Stability for Propane Dehydrogenation Reaction
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-17
    Ping Hu, Wan−Zhong Lang, Xi Yan, Xing−Fan Chen, Ya−Jun Guo
    更新日期:2018-01-17
  • Application of Ti-doped MoO2 microspheres prepared by spray pyrolysis to partial oxidation of n-dodecane
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-17
    Qusay Bkour, Kyungmin Im, Oscar G. Marin-Flores, M. Grant Norton, Su Ha, Jinsoo Kim
    更新日期:2018-01-17
  • 更新日期:2018-01-17
  • Catalytic oxidation of 1,2-dichloroethane over three-dimensional ordered meso-macroporous Co3O4/La0.7Sr0.3Fe0.5Co0.5O3: Destruction route and mechanism
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-17
    Mingjiao Tian, Chi He, Yanke Yu, Hua Pan, Louise Smith, Zeyu Jiang, Ningbo Gao, Yanfei Jian, Zhengping Hao, Qing Zhu
    更新日期:2018-01-17
  • 更新日期:2018-01-12
  • 更新日期:2018-01-11
  • Ethanol Synthesis Catalyzed by Single Ni Atom Supported on Mo6S8 support
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-10
    Xiaoli Zheng, Sibei Guo, Ling Guo
    更新日期:2018-01-10
  • Direct Z-Scheme heterojunction nanocomposite for the enhanced solar H2 production
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-09
    N. Subha, M. Mahalakshmi, M. Myilsamy, B. Neppolian, V. Murugesan
    更新日期:2018-01-10
  • Hydrodeoxygenation of guaiacol as a model compound of bio-oil in methanol over mesoporous noble metal catalysts
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-09
    E.A. Roldugina, E.R. Naranov, A.L. Maximov, E.A. Karakhanov
    更新日期:2018-01-09
  • Esterification of aqueous lactic acid solutions with ethanol using carbon solid acid catalysts: Amberlyst 15, sulfonated pyrolyzed wood and graphene oxide
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-05
    Van Chuc Nguyen, Ngoc Quynh Bui, Pascale Mascunan, Thi Thu Ha Vu, Pascal Fongarland, Nadine Essayem
    更新日期:2018-01-05
  • Vanadium-zirconium catalyst on different support for hydroxylation of benzene to phenol with O2 as the oxidant
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-04
    Weitao Wang, Na Li, Leilei Shi, Yangmin Ma, Xiufang Yang
    更新日期:2018-01-05
  • Developing Reactive Catalysts for Low Temperature Oxidative Coupling of Methane: On the Factors Deciding the Reaction Performance of Ln2Ce2O7 with Different Rare Earth A sites
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-04
    Junwei Xu, Liang Peng, Xiuzhong Fang, Ziyang Fu, Wenming Liu, Xianglan Xu, Honggen Peng, Renyang Zheng, Xiang Wang
    更新日期:2018-01-05
  • Oxidation of Aromatic Oxygenates for the Production of Terephthalic Acid
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-04
    Konstantinos A. Goulas, Mika Shiramizu, James R. Lattner, Basudeb Saha, Dionisios G. Vlachos
    更新日期:2018-01-05
  • Photocatalytic synthesis of 2,5-diformylfuran from 5-hydroxymethyfurfural or fructose over bimetallic Au-Ru nanoparticles supported on reduced graphene oxides
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-03
    Ben Ma, Yingyong Wang, Xiaoning Guo, Xili Tong, Chang Liu, Yunwei Wang, Xiangyun Guo
    更新日期:2018-01-04
  • Mg/Ga mixed-oxide catalysts for phenol methylation: outstanding performance in 2,4,6-trimethylphenol synthesis with co-feeding of water
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2018-01-03
    Tommaso Tabanelli, Stefano Cocchi, Bianca Gumina, Lorella Izzo, Massimo Mella, Sauro Passeri, Fabrizio Cavani, Carlo Lucarelli, Jan Schütz, Werner Bonrath, Thomas Netscher
    更新日期:2018-01-03
  • Alkylation of O-xylene and Styrene Catalyzed by Cross-linked Poly Acidic Ionic Liquids Catalyst with Novel Mesoporous-macroporous Structure
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-30
    Huaying Gao, Yuming Zhou, Xiaoli Sheng, Shuo Zhao, Chao Zhang, Jiasheng Fang, Beibei Wang
    更新日期:2017-12-31
  • Hydrotalcite-derived Co/Mg(Al)O as a stable and coke-resistant catalyst for low-temperature carbon dioxide reforming of methane
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-30
    Dalin Li, Shuping Xu, Kai Song, Chongqi Chen, Yingying Zhan, Lilong Jiang
    更新日期:2017-12-31
  • 更新日期:2017-12-31
  • Effect of Si/Al2 ratios in Mo/H-MCM-22 on methane dehydroaromatization
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-28
    Tae Hwan Lim, Kihun Nam, In Kyu Song, Kwan-Young Lee, Do Heui Kim
    更新日期:2017-12-31
  • Effect of Cobalt Loading on Structure and Catalytic Behavior of CoOx/SiO2 in CO2-Assisted Dehydrogenation of Ethane
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-28
    Rajesh Koirala, Olga V. Safonova, Sotiris E. Pratsinis, Alfons Baiker
    更新日期:2017-12-31
  • Promoting deoxygenation of triglycerides via Co-Ca loaded SiO2-Al2O3 catalyst
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-28
    N. Asikin-Mijan, H.V. Lee, J.C. Juan, A.R. Noorsaadah, Hwai Chyuan Ong, S.M. Razali, Y.H. Taufiq-Yap
    更新日期:2017-12-31
  • Ethyl benzene oxidative dehydrogenation to styrene on Al-B and Al-B-Sb catalysts
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-28
    Abdulrahim A. Al-Zahrani, Nagaraju Pasupulety, Muhammad A. Daous, Hafedh Driss, Arshid M. Ali, Sharif F. Zaman, Lachezar A. Petrov
    更新日期:2017-12-31
  • Study of NO removal and resistance to SO2 and H2O of MnOx/TiO2, MnOx/ZrO2 and MnOx/ZrO2–TiO2
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-27
    Bohan Jia, Jiaxiu Guo, Luo Hongdi, Song Shu, Ningjie Fang, Jianjun Li
    更新日期:2017-12-27
  • 更新日期:2017-12-27
  • 更新日期:2017-12-27
  • Formation of NH3 and N2O in a modern natural gas three-way catalyst designed for heavy-duty vehicles: the effects of simulated exhaust gas composition and ageing
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-24
    Pauliina Nevalainen, Niko M. Kinnunen, Anna Kirveslahti, Kauko Kallinen, Teuvo Maunula, Matthew Keenan, Mika Suvanto
    更新日期:2017-12-27
  • A sinter resistant Co Fischer-Tropsch catalyst promoted with Ru and supported on titania encapsulated by mesoporous silica
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-23
    Tumelo N. Phaahlamohlaka, Mbongiseni W. Dlamini, Mashikoane W. Mogodi, David O. Kumi, Linda L. Jewell, David G. Billing, Neil J. Coville
    更新日期:2017-12-27
  • 更新日期:2017-12-22
  • Enhanced catalytic ozonation performance of highly stabilized mesoporous ZnO doped g-C3N4 composite for efficient water decontamination
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-21
    Xiangjuan Yuan, Shule Duan, Guangyu Wu, Lei Sun, Gang Cao, Dongya Li, Haiming Xu, Qiang Li, Dongsheng Xia
    更新日期:2017-12-21
  • Highly efficient porous organic copolymer supported Rh catalysts for heterogeneous hydroformylation of butenes
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-19
    Yuqing Wang, Li Yan, Cunyao Li, Miao Jiang, Wenlong Wang, Yunjie Ding
    更新日期:2017-12-19
  • Low temperature prepared copper-iron mixed oxides for the selective CO oxidation in the presence of hydrogen
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-17
    M.P. Yeste, H. Vidal, A.L. García-Cabeza, J.C. Hernández-Garrido, F.M. Guerra, G.A. Cifredo, J.M. González-Leal, J.M. Gatica
    更新日期:2017-12-18
  • Catalytic evaluation of mesoporous metal oxides for liquid phase oxidation of styrene
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-15
    Ngonidzashe Masunga, Ginny Sasha Tito, Reinout Meijboom
    更新日期:2017-12-16
  • Facile synthesis of a superior MTP catalyst: Hierarchical micro-meso-macroporous ZSM-5 zeolites
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-13
    Hongyao Li, Yaquan Wang, Chunyang Fan, Chao Sun, Xiao Wang, Cui Wang, Xu Zhang, Shuhai Wang

    With the growing demand for propylene and the rapid depletion of petroleum resources, the methanol-to-propylene (MTP) reaction has aroused much interest in the industrial and academic research fields as an alternative route to produce propylene. Developing a highly efficient MTP catalyst by adopting a facile, efficient route is currently an important research goal. It is clear that the synthesis of a hierarchical micro-meso-macroporous ZSM-5 zeolite is regarded as the ideal strategy owing to its ability to minimize coke formation and to produce maximal catalytic efficiency in the MTP reaction. In this study, a superior MTP catalyst with a hierarchical micro-meso-macroporous structure (denoted as M-ZSM-5) has been successfully developed based on the passivation effect and the strong self-condensation of the short-chain organosilane 3-aminopropyltrimethoxy-silane (APTES) on the surfaces of nanocrystals in a quasi-solid-state system. This environmentally friendly synthetic strategy is operationally simple, with a high yield (above 80 %) and low cost and thus has considerable potential for industrial applications. In the quasi-solid-state system, APTES not only induced the formation of ultrafine nanocrystals but also ensured that these ultrafine nanocrystals were assembled in situ into hierarchical micro-meso-macroporous ZSM-5 zeolites. When applied to the methanol-to-propylene (MTP) reaction, the synthesized MZ-x (x = 1–5) zeolites exhibited a longer catalytic lifetime (31 h - 89 h) (at a high weight hourly space velocity of 8 h-1) than that of a commercial ZSM-5 catalyst (denoted as C1Z-1)(11 h), which are nearly three times and eight times longer than that of the C1Z-1 sample. In addition, the MZ-x (x = 1–5) catalysts also present a slightly higher propylene selectivity (39.92 %–41.89 %), butylene selectivity (22.29 %–23.65 %) and light olefins (C2= − C4 = ) selectivity (69.19 % ~ 71.43 %) than that of the C1Z-1 (39.86 %, 21.70 %, 68.46 %). These results were attributed to the abundant mesopores and macropores of M-ZSM-5 built by the ultrafine nanocrystals, offering a shorter diffusion path and more-accessible active sites for reaction.

    更新日期:2017-12-13
  • Synergistic effects of Nb2O5 promoter on Ru/Al2O3 for an aqueous-phase hydrodeoxygenation of glycerol to hydrocarbons
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-12
    Seongho Jeon, Yong Min Park, Jaeyeong Park, Kasi Saravanan, Hae-Kwon Jeong, Jong Wook Bae
    更新日期:2017-12-13
  • Effect of alkali and alkaline earth metal on Co/CeO2 catalyst for the water-gas shift reaction of waste derived synthesis gas
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-11
    Yeol-Lim Lee, Ajay Jha, Won-Jun Jang, Jae-Oh Shim, Chandrashekhar V. Rode, Byong-Hun Jeon, Jong Wook Bae, Hyun-Seog Roh

    We prepared a series of alkali (Na and K) and alkaline earth metal (Ca and Ba) promoted Co/CeO2 catalysts to investigate the effect of the promoter on the catalytic performance of the catalyst in the high-temperature water-gas shift (WGS) reaction of waste derived synthesis gas. Interestingly, alkali metal promoted catalysts deactivated rapidly compared to alkaline earth metal promoted catalysts. Alkaline earth metal promoted catalysts showed relatively higher stability (> 50 h) even at a very high gas hourly space velocity of 143,000 h−1. X−ray diffraction (XRD) and transmission electron microscopy (TEM) results reveal that the higher stability of the alkaline earth metal promoted catalysts was due to the strong resistance to sintering, showing a relatively small crystallite size of metallic cobalt compared to the alkali metal promoted catalysts after WGS reaction.

    更新日期:2017-12-11
  • Influence of H2O and H2S on the Composition, Activity, and Stability of Sulfided Mo, CoMo, and NiMo Supported on MgAl2O4 for Hydrodeoxygenation of Ethylene Glycol
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-10
    Trine Marie Hartmann Dabros, Abhijeet Gaur, Delfina Garcia Pintos, Paul Sprenger, Martin Høj, Thomas Willum Hansen, Felix Studt, Jostein Gabrielsen, Jan-Dierk Grunwaldt, Anker Degn Jensen

    In this work, density functional theory (DFT), catalytic activity tests, and in-situ X-ray absorption spectroscopy (XAS) was performed to gain detailed insights into the activity and stability of MoS2, Ni-MoS2, and Co-MoS2 catalysts used for hydrodeoxygenation (HDO) of ethylene glycol upon variation of the partial pressures of H2O and H2S. The results show high water tolerance of the catalysts and highlight the importance of promotion and H2S level during HDO. DFT calculations unraveled that the active edge of MoS2 could be stabilized against S-O exchanges by increasing the partial pressure of H2S or by promotion with either Ni or Co. The Mo, NiMo, and CoMo catalysts of the present study were all active and fairly selective for ethylene glycol HDO at 400 °C, 27 bar H2, and 550-2200 ppm H2S, and conversions of ≈ 50-100 %. The unpromoted Mo/MgAl2O4 catalyst had a lower stability and activity per gram catalyst than the promoted analogues. The NiMo and CoMo catalysts produced ethane, ethylene, and C1 cracking products with a C2/C1 ratio of 1.5-2.0 at 550 ppm H2S. This ratio of HDO to cracking could be increased to ≈ 2 at 2200 ppm H2S which also stabilized the activity. Removing H2S from the feed caused severe catalyst deactivation. Both DFT and catalytic activity tests indicated that increasing the H2S concentration increased the concentration of SH groups on the catalyst, which correspondingly activated and stabilized the catalytic HDO performance. In-situ XAS further supported that the catalysts were tolerant towards water when exposed to increasing water concentration with H2O/H2S ratios up to 300 at 400-450 °C. Raman spectroscopy and XAS showed that MoS2 was present in the prepared catalysts as small and highly dispersed particles, probably owing to a strong interaction with the support. Linear combination fitting (LCF) analysis of the X-ray absorption near edge structure (XANES) spectra obtained during in-situ sulfidation showed that Ni was sulfided faster than Mo and CoMo, and that Mo was sulfided faster when promoted with Ni. Extended X-ray absorption fine structure (EXAFS) results showed the presence of MoS2 in all sulfided catalysts. Sulfided CoMo was present as a mixture of CoMoS and Co9S8, whereas sulfided NiMo was present as NiMoS.

    更新日期:2017-12-10
  • Base free oxidation of 1,6-hexanediol to adipic acid over supported noble metal mono- and bimetallic catalysts
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-09
    Modibo MOUNGUENGUI-DIALLO, François VERMERSCH, Noémie PERRET, Catherine PINEL, Michèle BESSON

    1,6-Hexanediol is an emerging building-block chemical, which may be derived from biomass and can produce adipic acid for the synthesis of polymers. A series of supported Pt, Bi-Pt, Au, Pd, Au-Pd, and Au-Pt catalysts were prepared and evaluated in the aerobic oxidation of 1,6-hexanediol to adipic acid in aqueous solution without the addition of a base or an acid. The influences of various molar ratios of the metals in the bimetallic systems and the support (C, ZrO2) were studied. Under the conditions used, bismuth did not promote the catalytic performance of Pt catalysts. On the other hand, formation of an alloy of Au-Pd or Au-Pt made the catalysts very effective. A yield of adipic acid of ca. 96% was achieved at 70°C under 40 bar of air over the Au-Pt catalyst supported on zirconia with a Au/Pt molar ratio of about 1. Recycling tests revealed the possibility to use the catalyst up to 6 times without significant changes in its catalytic performance.

    更新日期:2017-12-10
  • Dichloromethane oxidation over FexZr1-x oxide catalysts
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-08
    Zhen Zhang, Hangqi Xia, Qiguang Dai, Xingyi Wang

    FexZr1-x-S mixed oxide catalysts were prepared by precipitation of FeSO4 and ZrOCl2, and used in catalytic oxidation of dichloromethane (DCM). Analyses by a series of characterization technologies reveal that Fe-O-Zr solid solution with tetragonal ZrO2 or α-Fe2O3 structure can be formed, dependent on Fe/Fe+Zr ratio. Residual SO42- species obtained from FeSO4 precursor exist in a form of bridged bidentate complex with Zr4+ or Fe3+ ion, which increases acidity significantly. FexZr1-x-S catalysts with Fe/Fe+Zr of 0.2~0.5 possess high contents of both SO42- and surface oxygen, and are highly active in catalytic combustion of DCM with T90 below 320 °C and TOFs at 200 °C of 0.98 ~ 1.89 μmol/(m2·min). Another test shows that the activity for the other CVOVs oxidation over Fe0.5Zr0.5-S is 1,2-dichloroethane > dichloromethane > trichloroethylene > 1,2-di chlorobenzene. Because the substitution of Cl species for surface oxygen is retarded, high stable activity maintains within reaction temperatures for at least 80 h. In situ FT-IR indicates that DCM is adsorbed and activated mainly through the formation of chloromethyl sulfate, which is oxidized quickly into formate ion. The synergism between SO42- complex anchoring on Zr-O-Fe solid solution and surface oxygen obtained from Fe2O3 cluster or nano-particles promotes the oxidation of formate.

    更新日期:2017-12-10
  • Photocatalytic synthesis of vanillin using N-doped carbon nanotubes/ZnO catalysts under UV-LED irradiation
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-07
    Maria J. Sampaio, Anas Benyounes, Philippe Serp, Joaquim L. Faria, Cláudia G. Silva

    ZnO synthesized by solid-state thermal process was combined with different contents of nitrogen-doped carbon nanotubes (N-CNT). The materials were characterized by several techniques including thermogravimetric analysis, N2 adsorption-desorption isotherms, scanning and transmission electron microscopies, and diffuse reflectance UV-Vis and photoluminescence spectroscopies. The performance of neat ZnO and N-CNT/ZnO composite materials was evaluated in the selective photocatalytic oxidation of vanillyl alcohol into vanillin under UV-LED irradiation. The presence of the carbon phase in the composite materials (from 5 to 10 wt.%) revealed to be crucial for increasing the performance of the photocatalysts. The best performance for vanillyl alcohol oxidation was obtained using the composite containing 5% of carbon phase (5%N-CNT/ZnO), with an increase of 22% in vanillin concentration comparing to neat ZnO after 2 h reaction. This enhancement in the efficiency of ZnO by the introduction of the carbon phase is attributed to the action of N-CNT as effective electron scavengers for ZnO, as revealed by the photoluminescence quenching, inhibiting the recombination of electrons and holes.

    更新日期:2017-12-07
  • Improving the low-temperature hydrothermal stability of Cu-SAPO-34 by the addition of Ag for ammonia selective catalytic reduction of NOx
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-05
    Xiao Xiang, Yi Cao, Lijing Sun, Pengfei Wu, Lei Cao, Shutao Xu, Peng Tian, Zhongmin Liu

    Ag promoted Cu-SAPO-34 has been developed to improve the low-temperature hydrothermal stability of Cu-SAPO-34 for the NH3-SCR reaction. Kinetic tests show that the addition of Ag into Cu-SAPO-34 doesn’t change the reaction mechanism. The ion-exchanged Ag species, which decrease the Brønsted acid density and provide more Lewis acid sites with moderate acidity, have a protective effect on the SAPO framework against low-temperature steaming treatment (LTST). Higher surface Cu content is observed for CuAg2.25-SAPO-34, although CuAg2.25-SAPO-34 and Cu-SAPO-34 have similar content of isolated Cu ions. In situ DRIFTS studies demonstrate, for the first time, the NH3 molecules adsorbed on the weak/moderate acid sites (independent of the acid types such as Brønsted acid or Lewis acid) are more active than on the strong acid sites for the low-temperature SCR reaction. Compared with the original catalyst Cu-SAPO-34, the enhanced SCR activity of CuAg2.25-SAPO-34 after LTST is ascribed to the better preservation of total acid sites, higher moderate acid density (Lewis acid sites) and larger amount of surface Cu species on the CuAg2.25-SAPO-34 catalyst.

    更新日期:2017-12-07
  • The Influence of Porosity and Active Sites of Zeolites Y and Beta on the Co-Cracking of n-Decane and 2-Ethylphenol
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-02
    Moritz Heuchel, Christian Dörr, Roman Boldushevskii, Swen Lang, Elias Klemm, Yvonne Traa

    We investigated the cracking of n-decane and 2-ethylphenol as co-substrate in a 90/10 wt.-% mixture over zeolites Y and beta. The use of these substrates aimed to better understand the occurring chemistry in applications such as Co-FCC. We employed a number of different zeolites Y with different amounts of active sites and pore volumes. Additionally, the pore system of zeolite beta was modified by basic leaching. The materials were characterized by N2physisorption, ICP-OES, XRD, 27Al, 1H, 13C MAS NMR, NH3-TPD, IR and TGA. It was found that the activity of the catalysts depends on the number of Brønsted acid sites as determined by NMR spectroscopy. Also most important is the mesopore volume/mesopore surface which is beneficial for the diffusion towards the micropores, especially for zeolite Y that is able to deoxygenate phenols.

    更新日期:2017-12-02
  • Silica deposition as an approach for improving the hydrothermal stability of an alumina support during glycerol aqueous phase reforming
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-02
    Fang Liu, Chukwuemeka Okolie, Ryan M. Ravenelle, John C. Crittenden, Carsten Sievers, Pieter C.A. Bruijnincx, Bert M. Weckhuysen

    Silica deposition on the benchmark aqueous phase reforming (APR) catalyst Pt/γ-Al2O3 is studied to prevent or limit hydrolytic attack of the support under hydrothermal APR conditions, for which boehmite formation by support hydration is a known cause for catalyst deactivation. Tetraethyl orthosilicate (TEOS) is employed as a silicon source in a straightforward liquid-phase, silylation process followed by catalyst calcination and reduction. Characterization by X-ray diffraction, temperature-programmed desorption of NH3, infrared, 27Al nuclear magnetic resonance and X-ray photoelectron spectroscopy of the fresh catalysts suggests that silica addition occurs preferentially on the support surface, resulting in weak Brønsted acid sites as well as in the formation of Si-O-Al linkages at the expense of specific surface Lewis acid sites. Silylation and calcination of Pt/γ-Al2O3 causes partial blockage of the metal surface area (12% loss), whereas γ-Al2O3 surface silica modification prior to Pt deposition makes controlled metal deposition difficult. Catalytic performance tests show the overcoated samples to be active in the APR of 5 wt.% glycerol, albeit with lower H2 production rates compared to the benchmark catalyst. Characterization of spent APR catalysts clearly demonstrates that silylation/calcination treatments effectively slows down the transformation of the γ-Al2O3 support due to the formation of a Si-O-Al interface. Overall, the lifetime of the catalyst is increased three-fold as a result of the surface overcoating treatment, with repetitive recycling ultimately leading to loss of the protective silica layer.

    更新日期:2017-12-02
  • Impact of desilication of desilication of *BEA zeolites on the catalytic performance in hydroisomerization of n-C10
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-12-02
    H. Sammoury, J. Toufaily, K. Cherry, T. Hamieh, Y. Pouilloux, L. Pinard

    Two commercial nanocrystal *BEA zeolites CP811 (P1) and CP814E (P2) with same total Si/Al ratio (Si/Altotal = 12) but different textural properties, were desilicated using different alkaline treatment; classical in presence of NaOH alone, or incorporated with a pore directing agent. P1 was desilicated by NaOH alone, and NaOH+TPABr, while P2 was desilicated in presence of NaOH+TBAOH. A synthesized microcrystal *BEA zeolite with Si/Al total ratio of 36, was also desilicated with NaOH alone, NaOH+TPABr, and NaOH+TBAOH. All parent and desilicated zeolites were transformed into bifunctional catalysts by platinum loading and were tested in the hydroisomerization of n-C10. P1 zeolite was impregnated with different Pt contents to insure maximum activity and selectivity towards isomers products. It has been seen that the improvement of the textural properties by desilication using the different pore directing agents, was not always the cause behind an increase or decrease in the activity and selectivity of the catalyst, but rather was more the location of the Pt particles and their predicted distance from the acidic sites. However, the presence of an interplay between the inter- and intracrystalline mesopores, with the additional parameter of Pt-H+ distance, serve better as combined characteristics behind the final activity and selectivity.

    更新日期:2017-12-02
  • Dual Combining Transition Metal Hybrid Nanoparticles for Ammonia Borane Hydrolytic Dehydrogenation
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-26
    Bilge Coşkuner Filiz, Aysel Kantürk Figen, Sabriye Pişkin

    A new hybrid of nanoparticles designed to enable efficient catalysis for hydrogen generation (NPs) include a dual combination of Co, Ni, and Cu transition metals. These nanoparticles are made by altering metals and molar ratios (x: 0.25, 0.50, and 0.75) and designed for hydrogen generation by hydrolytic dehydrogenation of ammonia borane (NH3BH3). A synergistic effect of dual combination on the induction period and dehydrogenation rate is found. Kinetic interpretation and thermodynamic studies demonstrate that the Co0.50Cu0.50/NPs catalyst shows superior activation (DR=10.56 l H2.min-1.g-1cat and Ea=38.12 kJ.mol-1) with a synergistic effect and meet the criteria of The United States Department of Energy (DOE) targets for onboard hydrogen production systems for light-duty vehicles.

    更新日期:2017-11-28
  • Nanoparticles of Ce, Sr, Co in and out the multi-walled carbon nanotubes applied for dry reforming of methane
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-26
    Camila Emilia Figueira, Paulo Firmino Moreira Junior, Reinaldo Giudici, Rita Maria de Brito Alves, Martin Schmal

    In chemical terms one of the most attractive properties of CNTs is their ability to encapsulate metal nanoparticles and to confine them inside the cavities. In spite of the synthetic difficulties met when trying to access the CNTs cavity, this work aims to synthesize nanocomposites on multi-walled carbon nanotubes (MWCNTs), with Ce and Sr nanoparticles inside and Co nanoparticles outside the CNTs, taking the advantage of the fact that Cerium allows the material to act as an oxygen storage. As reference, the Ni@MWCNT/Ni catalyst was prepared. We obtained the insertion of CeSr and Ni particles inside the wall nanotubes with diameters below 30 nm and Co or Ni outside of the carbon nanotubes. These catalysts were characterized by N2 adsorption (BET), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and x-ray diffraction (XRD). The activity of the synthesized catalysts was tested through the dry reforming reaction of methane to produce synthesis gas for different temperatures (500–700 °C) and showed that the synthesized CeSr@MWCNT/Co exhibited high conversions and very similar to the Ni@MWCNT/Ni catalyst.

    更新日期:2017-11-28
  • Effect of H2S on the mechanisms of naphthene ring opening and isomerization over Ir/NaY: a comparative study of decalin, perhydroindan and butylcyclohexane hydroconversions
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-24
    Elodie Blanco, Laurent Piccolo, Dorothée Laurenti, Luca di Felice, Nelly Catherin, Chantal Lorentz, Christophe Geantet, Vincenzo Calemma

    Selective ring opening is an important hydrotreating process for gas oil upgrading. In this work, we have used an Ir/NaY bifunctional catalyst -highly efficient in sulfur-free conditions- as a reference system to assess the effect of H2S impurity concentration (0-1 %) on the kinetics and mechanisms of naphthene conversion under high hydrogen pressure (5 MPa). Three model naphthenic molecules (decalin, perhydroindan and butylcyclohexane) were compared to evaluate the influence of the ring size (C5 vs C6) and number (1 vs 2). The numerous reaction products were identified, quantified and classified by using two-dimensional gas chromatography (GC×GC). In the absence of sulfur, it is confirmed that C5 rings are opened faster than C6 rings, and that single-ring naphthenes are converted faster than double-ring naphthenes. The presence of H2S, even at concentrations as low as 30 ppm, drastically and irreversibly changes the dominant catalytic function (from metallic to acidic), mechanism (from dicarbene-mediated to carbocation rearrangement) and family of products (from ring-opening products to skeletal-isomerization products). Together with experiments at variable reactant conversion, these results allow us to propose mechanistic reaction schemes for the three naphthenes under similar conditions, both for sulfur-free and sulfur-rich atmospheres.

    更新日期:2017-11-24
  • The effect of the hydrotalcite structure and nanoparticle size on the catalytic performance of supported palladium nanoparticle catalysts in Suzuki cross-coupling
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-22
    Beau Van Vaerenbergh, Kevin De Vlieger, Kyle Claeys, Gertjan Vanhoutte, Jeriffa De Clercq, Pieter Vermeir, An Verberckmoes

    An uncalcined HT supported Pd-NP catalyst was synthesized via co-precipitation, i.e., PdHT_100RED_20, and benchmarked against a Pd impregnated HT catalyst, i.e., Pd@HT_500RED_20. TEM analysis pointed out that the largest NPs (6.5 nm) were found in the co-precipitated catalyst because of its weaker steric NP confinement, compared to the benchmark catalyst (3.2 nm). The PdHT_100RED_20 had a significantly higher catalytic performance (60% conversion, 1.85% leaching) than Pd@HT_500RED_20 (19%, 0.98%) due to lack of calcination resulting in an ordered, and thus, more accessible HT structure in combination with its high support basicity. Both catalysts showed low Pd leaching confirming the suitability of HTs as NP support. Focusing on PdHT_100, the effect of the reduction temperature on the NP size and catalytic performance was investigated. NP size distribution analysis showed that the smallest NPs were found in PdHT_100RED_0 (5.3 nm), resulting in a higher catalytic performance (67%, 2.28%) when compared to PdHT_100RED_20 (6.5 nm). Performing the reduction at higher temperatures, i.e., at 60°C (5.7 nm), caused an extremely low catalytic performance (13%, 0.20%). Reusing PdHT_100RED_20, a decrease in catalytic performance (45%) was observed. However, this decrease was less pronounced (50%) when a re-activation of the catalyst with Na2CO3 between consecutive runs was performed. Moreover, it was shown that the leached Pd species were able to re-deposit onto the support if high conversions were obtained, and thus, an almost quantitatively recovery from the reaction mixture can be achieved with retention of its catalytic activity (>99%).

    更新日期:2017-11-23
  • Novel access to verbenone via ruthenium nanoparticles-catalyzed oxidation of α-pinene in neat water
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-21
    Mariem Rauchdi, Mustapha Ait Ali, Alain Roucoux, Audrey Denicourt-Nowicki

    Aqueous suspensions of Ru(0) nanoparticles, stabilized with hydroxyethylammonium salts and possessing sizes around 2 nm, proved to be active and selective in the mild oxidation of α-pinene in the presence of tert-butylhydroperoxide, in neat water. Verbenone, a product of great interest for fine chemistry, was obtained as major product with yield up to 41% under optimized conditions. 2-hydroxy-3-pinanone was identified as a co-product of the reaction, but with very low amount (<7%). Kinetic investigations allowed determining the potential reaction intermediates and by-products. Moreover, mechanistic studies with radical scavengers confirmed that α-pinene oxidation mainly implies both carbon- and oxygen-centered radicals.

    更新日期:2017-11-22
  • B(C6F5)3 promotes the catalytic activation of [N,S]-ferrocenyl nickel complexes in ethylene oligomerization
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-21
    B. Rodríguez, D. Cortés-Arriagada, E.P. Sánchez-Rodríguez, R.A. Toscano, M.C. Ortega-Alfaro, J.G. López-Cortés, A. Toro-Labbé, R.S. Rojas

    The synthesis of new methallyl-ferrocenyl-thiazoline-nickel complexes [1-(2-thiazolin-2-yl)-2-(R-thio)-ferrocene-κ2N,S]-(η3-methallyl)nickel(II) [Y] (1-3, R = Me, i-Pr, Ph, Y = BF4-4, R = Me, Y = BAr´4-) by reaction with 2-ferrocenyl-2-thiazoline ligands L1-3 with [Ni-(η3-(CH2)2CMe)Cl]2 in presence of fluoroborate salts (Y = BAr´4-; BF4-) is reported. The complexes 1-4 were obtained in high yields, and characterized by 1H, 13C, 19F and 11B NMR, FTIR. The X-Ray diffraction analysis of 4 confirmed the formation of a single isomer containing a nickel center coordinated to L1 in a bidentate [N,S] fashion and to a η3-methallyl ligand. These complexes catalyzed efficiently the ethylene oligomerization when tris(pentafluorophenyl)borane (BCF) was used as co-activator. All catalytic precursors produced C4 and C6 fractions. Complex 1 showed higher activity with TOF 3006 h-1 at room temperature with selectivity of 86% to C4 fraction. In contrast, catalyst 2 was more selective to the formation of 1-butene, but with low activity. DFT-Computational studies of complex-BCF adducts show than these species behave as frustrated Lewis pairs, mainly stabilized by long-range interactions enhancing the acceptor character of the complexes. Structural modifications over the sulfanyl group tune the acceptor character of Ni center, affecting their catalytic performance.

    更新日期:2017-11-22
  • Ultrasound-assisted electrocatalytic hydrogenation in water
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-21
    Josinete Angela da Paz, Ayrlane Sales, Larissa Dias da Silva, Émerson Felipe Mendonça da Silva, José Angelo Peixoto da Costa, Marcelo Navarro, Frederico Duarte de Menezes, Márcio Vilar

    The optimum conditions for the electrocatalytic hydrogenation of (R)-(+)-pulegone in water, using ultrasound (continuous or pulsed mode) and a nickel sacrificial anode have been determined. The continuous ultrasound (14 W), without temperature control, showed to be a most effective technique if compared with pulses of 0.2 s applied after each second. The sonication of the reaction solution presented a slight stereochemical effect on the product distribution, and its magnitude depends on both the ultrasound power and the mode. Simultaneous ultrasound irradiation during electrochemical process showed a synergetic effect, able to generate H radical from water H-O bond rupture, in addition to the H radicals formed by the electrochemical reduction of water on the electrode surface, increasing both current efficiency and conversion yields. Chitosan microspheres were use in the removal of nickel ions of the aqueous medium showing an adsorption efficiency of 64%.

    更新日期:2017-11-22
  • Synthesis and Stabilization of Small Pt Nanoparticles on TiO2 Partially Masked by SiO2
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-21
    Zhenyu Bo, Sol Ahn, M. Alexander Ardagh, Neil M. Schweitzer, Christian P. Canlas, Omar K. Farh, Justin M. Notestein

    Controlling metal nanoparticle size and preserving metal dispersion at elevated temperature remain key challenges in designing new supported metal catalysts. Many methods have been proposed to stabilize metal nanoparticles for catalysis, but the use of specialized equipment or metal precursors can limit the application of these methods for scalable production. Here, we demonstrate a synthesis strategy to improve the dispersion and thermal stability of Pt nanoparticles on an oxide support. A thin SiO2 coat (<2 nm) was deposited on TiO2 through repeated condensation cycles of tetraethyl orthosilicate (TEOS) with or without an organic template on the surface. H2PtCl6 was deposited using wetness impregnation, and the samples were dried, calcined, and reduced. The as-synthesized Pt nanoparticles are 1-2 nm by TEM and maintain dispersion >45% by CO chemisorption even after prolonged heating at 500 °C, whereas Pt nanoparticles on unmodified TiO2 are less dispersed (~33%) and their dispersion falls further upon prolonged heating. Ethylene hydrogenation demonstrates that the Pt nanoparticles on modified TiO2 preserve the catalytic activities of Pt on unmodified TiO2. The use of wet chemistry-based oxide modification and wetness impregnation makes this strategy a scalable and generalizable synthesis method to prepare other supported metal nanoparticles for catalysis applications.

    更新日期:2017-11-22
  • Self-assembled ZnAl-LDH/PMo12 nano-hybrids as effective catalysts on the degradation of methyl orange under room temperature and ambient pressure
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-21
    Yin Xu, Wenjie Huang, Xiaoying Chen, Fei Ge, Runliang Zhu, Luyi Sun

    ZnAl-layered double hydroxide/H3PMo12O40 (ZnAl-LDH/PMo12) nano-hybrids were prepared by self-assembly between positively charged LDH nano-sheets and negatively charged PMo12 nano-clusters. The catalytic performance of ZnAl-LDH/PMo12 (ZAM) nano-hybrids on methyl orange (MO) degradation under room temperature and ambient pressure was investigated. The self-assembly process was evidenced by various characterization results, including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption measurements, and X-ray photoelectron spectroscopy, which also suggested that the structure and morphology of the ZnAl-LDH/PMo12 hybrids played a critical role in their catalytic performance. The ZAM nano-hybrid with a 1:1.59 molar ratio of ZnAl-LDH to PMo12 exhibited an excellent catalytic activity for MO degradation, with a 74.2% discoloration rate and a 66.2% total organic carbon (TOC) removal efficiency. After five cycles of reactions, the discoloration rate remained at 62.5%. This high catalytic activity might be attributed to the formation of O2•−, which was generated from the reduction of the dissolved oxygen by PMo12. Overall, the results show that the formation of novel nano-hybrid catalysts through self-assembly of LDH nano-sheets with PMo12 nano-clusters leads to a significant improvement in the catalytic activity and stability of Mo based catalysts under room temperature and ambient pressure.

    更新日期:2017-11-21
  • Bimetallic Ni-M (M = Co, Cu and Zn) supported on attapulgite as catalysts for hydrogen production from glycerol steam reforming
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-21
    Yishuang Wang, Mingqiang Chen, Zhonglian Yang, Tian Liang, Shaomin Liu, Zhongshan Zhou, Xiaojing Li

    Monometallic Ni and bimetallic Ni-Co, Ni-Cu, and Ni-Zn catalysts supported on attapulgite (ATP) were prepared by chemical precipitation method and evaluated in the glycerol steam reforming (GSR) reaction under the following conditions W/G = 9, N2 flow ratio = 0.16 L/min and GHSV = 9619 h-1. The prepared calcined and/or reduced samples were characterized by ICP-OES, N2 adsorption-desorption, XRD, TEM, FT-IR, XPS and H2-TPR. The analysis results showed the addition of second metals obviously decreased the crystal size and suppressed the reducibility of active metal, by improving the metal-support interaction. These were optimized characters could promote the steam reforming reaction and water-gas shift reaction (WGSR) to improve the catalytic performance. The experimental results of catalytic activity revealed the glycerol conversions and H2 yields over bimetallic catalysts were significantly higher than those over Ni/ATP catalyst. Among them, the Ni-Cu/ATP exhibited the highest the highest glycerol conversions and H2 yield in GSR reaction, while it had larger particle size (12.2 nm) than Ni-Co/ATP (8.6 nm) and Ni-Zn/ATP (10.3 nm), and the higher reducibility than other two bimetallic catalysts. It may be deduced that the crystal size and reducibility of catalyst all showed pivotal to impart suitable catalytic activity, while these characteristics should have an optimal proportion for obtaining the outstanding catalytic performance. The effect of temperature on catalytic performance over all catalysts was also investigated. It was found that increasing temperature was favorable for glycerol conversions and H2 yield, while the increase rate of H2/CO ratio was suppressed and CO/CO2 ratio were increased for all catalysts at high temperature range of 600 - 700 oC. It was attributed to that increasing temperature although improved the breakage of C-C, C-H, and C-O bonds in glycerol, the WGSR mainly side-reaction for producing H2 was suppressed. The long-term experiments (30 h) were also conducted over all catalysts at W/G = 9, T= 600 oC, N2 flow ratio = 0.16 L/min and GHSV = 9619 h-1. The results demonstrated the outstanding stability was obtained over Ni-Zn/ATP catalyst. In order to account for the causes resulted in catalyst deactivation, all spent catalysts were characterized by XRD, TEM, TPO and TG-DTG. The results shown catalyst deactivation was mainly affected by the sintering of active species and coke formation on catalyst surface. The Ni-Zn/ATP bimetallic catalyst showed the outstanding stability attributed to the excellent anti-sintering and carbon deposition, which resulted from the formation of unique metal-support interaction.

    更新日期:2017-11-21
  • INTERCONNECTION BETWEEN FEED COMPOSITION AND Ni/Co RATIO IN (La-Ni-Co-O)-BASED PEROVSKITES AND ITS EFFECTS ON THE STABILITY OF LPG STEAM REFORMING
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-20
    Cícero N. Ávila-Neto, Kátia D. Oliveira, Kimberly F. Oliveira, Aline M.M. Arouca, Rondinele A.R. Ferreira, Carla E. Hori

    Nickel-based perovskites (La-Ni-O) partially substituted with cobalt were tested for steam reforming of Liquefied Petroleum Gas (LPG), and analyzed by a series of in situ techniques. In situ X-ray diffraction (XRD) analyses showed that, depending on the fraction of substituted Ni, the perovskites go through one or two reduction stages before decomposing into Ni0/Co0 and La2O3. Extended X-ray absorption fine structure (EXAFS) data indicated that the nanoparticle’s surface are enriched with Co after reduction, but the Ni atoms migrate to the surface and overlay the former Co shell soon after feeding the LPG steam reforming mixture. In samples synthesized with a low Co/Ni ratio, the Ni surface layer oxidizes after a few hours under reaction conditions, showing signs of deactivation. The oxidation could be prevented by decreasing the water/LPG feed ratio, which reactivated the catalyst. The use of a proper water/LPG feed ratio coupled with the suitable Co/Ni ratio in the synthesis of perovskite precursors is essential to keep the catalysts active during LPG steam reform.

    更新日期:2017-11-20
  • From medium chain fatty alcohol to jet fuel: Rational integration of selective dehydration and hydro-processing
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-12
    Mingli He, Meng Wang, Guanglu Tang, Yunming Fang, Tianwei Tan

    Middle chain fatty alcohols, which can be easily obtained from bio-synthesis and fatty acid hydro-treatment, were used as a renewable resource to produce alternative jet fuels by rational integration of selective dehydration and hydro-processing. Various catalysts such as ZSM-22, Al-MCF and ZSM-5 with different textural and acidic properties were tested in the dehydration step. It was found that the structural and acidic properties have significant influences on the dehydration performance and product distribution. After Pt introduction, the fatty alcohols can be converted into paraffins with different isomerization degrees. The different integrations of dehydration and hydro-processing steps resulted in different medium chain fatty alcohol to jet fuel production processes. Three different production processes, one-step hydro-isomerization over Pt/ZSM-22, dehydration (Al-MCF)/hydro-isomerization (Pt/ZSM-22) and dehydration (ZSM-22)/hydro-processing (Pt/MCF) were developed and tested. The dehydration (Al-MCF)/hydro-isomerization (Pt/ZSM-22) process, which provides the highest iso-paraffin yield, was used for conversion of a commercially available alcohol mixture in a pilot scale reactor. The product obtained from such pilot scale experiment had a freezing point of <−60 °C and met the requirements of ASTM 7566 specification except for density.

    更新日期:2017-11-13
  • Hydrodeoxygenation activity of W modified Ni/H-ZSM-5 catalyst for single step conversion of levulinic acid to pentanoic acid: An insight on the reaction mechanism and structure activity relationship
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-09
    Vijay Kumar Velisoju, Naresh Gutta, James Tardio, Suresh K. Bhargava, Krishna Vankudoth, Anjaneyulu Chatla, Sudhakar Medak, Venugopal Akula

    Direct conversion of levulinic acid (LA) to pentanoic acid (PA) was achieved over the W modified Ni supported on SiO2, Al2O3 and H-ZSM-5 catalysts at 270 °C and ambient H2 pressure in a continuous flow fixed-bed reactor. The interaction between Ni and W was the key which is rationalized by XRD, XPS, TGA-TPD of NH3, DRIFTS, TEM, CO-pulse chemisorption and H2-TPR analyses. PA rate of ∼1.24 μmol s−1 gcat−1 (with highest LA conversion ∼40% and selectivity ∼65% after 6 h of continuous operation) achieved over W modified Ni/H-ZSM-5 catalyst compared to others. The better PA rate on Ni-W/H-ZSM-5 catalyst was manifested by the presence of not only strong acid sites and also due to a higher number surface ionic Ni species which were responsible for the ring opening of γ-valerolactone (GVL) and the β-proton abstraction that occurred on basic sites. On the contrary, Ni-W/SiO2, Ni-W/Al2O3 and Ni/H-ZSM-5 were found to be less selective towards PA and more selective towards GVL, exemplifying the role of support and W for the PA selectivity. The surface active sites for the PA formation are illustrated by using probes such as pyridine (strong base) and/or acetone (mild base) and formic acid adsorbed DRIFT spectroscopy. Based on the product distribution, a plausible surface mechanism was also elucidated and discussed.

    更新日期:2017-11-10
  • Electrostatic adsorption-microwave synthesis of palladium nanoparticles on graphene for improved cross-coupling activity
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-08
    S.E. Gilliland III, J. Meynard M. Tengco, Y. Yang, J.R. Regalbuto, C.E. Castano, B.F. Gupton

    Graphene materials as catalyst supports have shown tremendous promise for improving catalytic activity. Pd nanoparticles supported by graphene defects have been shown to improve catalytic activity in Suzuki reactions, but understanding their formation and factors that affect their formation is still elusive. In order to gain a better understanding of this phenomenon, a new synthetic method was developed combining strong electrostatic adsorption method for directed ionic Pd precursor uptake with a new solventless microwave irradiation method to simultaneously form Pd nanoparticles and graphene defect sites. Catalytic activities an order of magnitude higher than commercial Pd-carbon catalysts were obtained using this new method with low microwave powers, short reaction times, under atmospheric conditions, and without the use of reducing agents or solvents. The systematic comparison of catalysts synthesized from four different graphene materials and two different Pd precursors revealed Pd-graphene defects form through three routes that are affected by the initial oxygen content of graphene support and choice of ionic Pd precursor.

    更新日期:2017-11-10
  • Coupled Reforming of Methane to Syngas (2H2-CO) over Mg-Al Oxide Supported Ni Catalyst
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-06
    Maoshuai Li, André C. van Veen

    We report bi-reforming and coupled reforming of methane with carbon dioxide, steam and/or oxygen to produce syngas over Ni supported on Mg-Al mixed oxide. The catalyst has been characterised in terms of specific surface area, TPR, XRD, TGA-DTG, SEM and TPO-MS analysis. Ni/Mg-Al mixed oxide exhibited Ni particle size range (11–30 nm) with a mean of 20.7 nm. Syngas H2/CO = 2.0, suitable for methanol/Fischer-Tropsch fuel synthesis, has been achieved for both reactions (T = 1048 K, P = 1 atm). The impact of process parameters including temperature, feeding concentration and GHSV on conversion and H2/CO ratio has been demonstrated. The Ni catalyst suffered temporal activity decline in bi-reforming that can be linked to formation of carbon whiskers encapsulated Ni particles resulting in a loss of active sites. Coupled reforming delivered higher CH4 conversion and enhanced stability, but lower CO2 conversion than bi-reforming under similar conditions. The enhanced stability in coupled reforming can be attributed to lower carbon deposition on Ni particles due to combustion of carbon by oxygen.

    更新日期:2017-11-10
  • Oxidative dehydrogenation of ethane to ethylene: A promising CeO2-ZrO2-modified NiO-Al2O3/Ni-foam catalysts
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-06
    Zhiqiang Zhang, Jia Ding, Ruijuan Chai, Guofeng Zhao, Ye Liu, Yong Lu

    From macro- to nano-engineering of a promising CeO2-ZrO2-doped NiO-Al2O3/Ni-foam catalyst has been demonstrated for the oxidative dehydrogenation of ethane to ethylene (ODE), through facial wet chemical etching of a Ni-foam followed post modification with CeO2 and ZrO2. The NiO-Al2O3/Ni-foam (denoted as NANF) achieved a high ethane conversion of 25.2% but with a very low ethylene selectivity of 43.1% at 450 °C. ZrO2-doping of the NANF led to a remarkable improvement in the ethylene selectivity but serious deterioration of activity while the CeO2-doping showed an opposite effect. Co-doping of the NANF using optimal amount of CeO2 and ZrO2 markedly promoted not only the activity but also the selectivity to ethylene. For example, over the 1CeO2-5ZrO2-NANF (CeO2:1 wt%, ZrO2:5 wt%) catalyst, a high ethane conversion of 40.3% was obtained with a 60.6% ethylene selectivity for a feed gas of C2H6/O2/N2 = 1/1/8 at 500 °C and a gas hourly space velocity of 18,000 cm3 g−1 h−1, corresponding to a high ethylene productivity of 510 gEthylene kgcat−1 h−1. In nature, co-doping with CeO2 and ZrO2 synergistically tamed the NiO for selective H-abstraction of the ethane molecules other than over oxidation of them.

    更新日期:2017-11-10
  • Tuning Y-zeolite Based Catalyst with Copper for Enhanced Activity and Selectivity in Vapor Phase Hydrogenolysis of Glycerol to 1,2-Propanediol
    Appl. Catal. A Gen. (IF 4.339) Pub Date : 2017-11-04
    Harisekhar Mitta, Prem Kumar Seelam, Satu Ojala, Riitta L. Keiski, Putrakumar Balla
    更新日期:2017-11-05
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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