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  • Development of Highly Stable Low Ni Content Catalyst for Dry Reforming of CH4‐Rich Feedstocks
    ChemCatChem (IF 4.495) Pub Date : 2020-01-27
    Quan Luu Manh Ha; Henrik Lund; Carsten Kreyenschulte; Stephan Bartling; Hanan Atia; Than Huyen Vuong; Sebastian Wohlrab; Udo Armbruster
    更新日期:2020-01-27
  • Enzyme Immobilization on synthesized Nanoporous Silica Particles and their Application in a Bi‐enzymatic Reaction
    ChemCatChem (IF 4.495) Pub Date : 2020-01-27
    Claudia Engelmann; Narendhiran Ekambaram; Jens Johannsen; Oliver Fellechner; Thomas Waluga; Georg Fieg; Andreas Liese; Paul Daniel Bubenheim

    The application of enzymes presents a great advantage regarding highly selective reactions; however, it involves also challenges due to their sensitivity. Immobilization offers one strategy to overcome those challenges enabling enzyme stabilization, as well as retention. In the present study, covalent attachment on hydrophilic amino‐functionalized carriers is found to be the most promising immobilization method for the investigated reaction system. To achieve this, a novel method for preparation of silica particles with subsequent amino‐functionalization is developed to prepare spherical carriers for enzyme immobilization, whereby high porosities are obtained based on polymerization. With these particles, immobilization of an alcohol dehydrogenase and a formate dehydrogenase is realized with residual activities of 70% and 80% after 12 consecutive batches, respectively. The two immobilized enzymes are used in the reduction of cinnamyl aldehyde with in situ cofactor regeneration, obtaining a conversion of 100% and up to 10‐fold higher turnover numbers compared to the free enzyme.

    更新日期:2020-01-27
  • Catalytic Methylation of Aromatic Hydrocarbons using CO2/H2 over Re/TiO2 and H‐MOR catalysts
    ChemCatChem (IF 4.495) Pub Date : 2020-01-27
    Kah Wei Ting; Haruka Kamakura; Sharmin Poly; Takashi Toyao; S. M. A. Hakim Siddiki; Zen Maeno; Koichi Matsushita; Ken-ichi Shimizu

    A combined catalyst comprising TiO2‐supported Re (Re(1)/TiO2; Re = 1 wt%) and H‐MOR (SiO2/Al2O3 = 90) was found to promote the methylation of benzene using CO2 and H2. This catalytic system exhibited high performance with regard to the synthesis of methylated benzenes and gave high yields of total methylated products (up to 52% benzene‐based yield and 42% CO2‐based yield) under the reaction conditions employed in this study (pCO2 = 1 MPa; pH2 = 5 MPa; T = 250 °C; t = 20 h) in a batch reactor. Catalyst screening demonstrated that a combination of Re(1)/TiO2 and H‐MOR (SiO2/Al2O3 = 90) exhibited superior performance compared to other combinations of supported metal catalysts and zeolites in terms of both yield and selectivity for methylated benzenes.

    更新日期:2020-01-27
  • In‐situ Transmission Electron Microscope Techniques for Heterogeneous Catalysis
    ChemCatChem (IF 4.495) Pub Date : 2020-01-26
    Xi Liu; Bowen He; Yixiao Zhang; Liwei Chen

    The physicochemical properties of heterogeneous catalysts in static or inert environments often deviate greatly from the properties under in‐situ or working conditions. To gain an insightful understanding of realistic catalyst properties and the corresponding catalytic mechanisms, it is essential to identify and rationalize changes in catalysts under reaction conditions. In recent years, in‐situ transmission electron microscope (in‐situ TEM) techniques have been increasingly developed, offering a unique approach to visualize the evolution of heterogeneous catalysis with ultra‐high spatial resolution, good energy resolution and reasonable temporal resolution under controllable or even realistic catalytic conditions. In this review, we have summarized recent advances in the in‐situ TEM analysis of heterogeneous catalysis, which suggests the great potential of this technique in this important field. Furthermore, technical challenges and possible solutions are discussed.

    更新日期:2020-01-27
  • Nitrogen and Sulfur Co‐doped Carbon Nanosheets for Electrochemical Reduction of CO2
    ChemCatChem (IF 4.495) Pub Date : 2020-01-26
    Zhenhai Wen; Genxiang Wang; Mengyan Liu; Jingchun Jia; Huimin Xu; Baisheng Zhao; Keyuan Lai; Chaoyang Tu

    Conversing CO2 into value‐added chemicals endows electrochemical CO2 reduction reaction (CO2RR) with the potential to tackle over issues induced by the increased CO2 level in the atmosphere. The associated technological viability of this process is highly dependent on exploring efficient electrocatalysts. In this work, we successfully synthesized nitrogen and sulfur co‐doped carbon nanosheets (NS‐CNSs), which are comprehensively characterized by a variety of characterization techniques. When used as the catalyst for CO2RR, the NS‐CNSs exhibit remarkably high catalytic activity and selectivity with a faradaic efficiency of ~85.4% for CO production and long‐term durability. The superior performance of this material majorly originates from the unique nanosheets structure with large porosity and the co‐doped S and N in the nanosheets, which exposed larger electrochemical activity surface areas and more active sites for promoting CO2 reduction.

    更新日期:2020-01-27
  • Pr2O3 Supported Nano‐layered Ruthenium Catalyzed Acceptorless Dehydrogenative Synthesis of 2‐Substituted Quinolines and 1,8‐Naphthyridines from 2‐Aminoaryl Alcohols and Ketones
    ChemCatChem (IF 4.495) Pub Date : 2020-01-26
    Katsutoshi Nagaoka; Chandan Chaudhari; Katsutoshi Sato; Yuta Ogura; Shin-ichiro Miayahara

    Pr 2 O 3 supported Ru nanolayers and Ru nanoparticles catalysts were examined for the synthesis of quinolines. The Ru nanolayer was most active catalyst and showed a broad substrate scope. Structure‐activity relationship demonstrated that the metallic state and morphology of Ru as well as the basic site of Pr 2 O 3 were indispensable factors of this catalytic system.

    更新日期:2020-01-27
  • Tetraalkylammonium functionalized hydrochars as efficient supports for palladium nanocatalysts
    ChemCatChem (IF 4.495) Pub Date : 2020-01-25
    Tiago A. G. Duarte; Isabelle Favier; Christian Pradel; Luísa M. D. R. S. Martins; Ana P. Carvalho; Daniel Pla; Montserrat Gómez

    With the aim of preparing bio‐sourced supports with enhanced properties in catalysis, we devised an original strategy allowing the immobilization of metal nanoparticles. Thus, size‐controlled hydrochars with a high degree of hydroxyl functionalities, from both neat sucrose or modified with acrylic acid (10 wt. %), were derivatized with ether linkers containing ammonium groups. These non‐porous carbon‐based materials were used as suitable supports for the immobilization of palladium nanoparticles. The catalytic materials were synthesized by reduction of Pd(OAc) 2 to Pd(0) under H 2 atmosphere in the presence of the corresponding hydrochar, and fully characterized by standard methods. Among the different hydrochar‐supported palladium materials, those functionalized with tetraalkylammonium groups afforded heterogeneous catalysts, exhibiting high activity in hydrogenations of different types of substrates (alkynes, alkenes, and carbonyl and nitro derivatives). The most efficient catalyst was recycled up to ten runs without loss of catalytic behavior, in agreement with the unchanged catalytic materials after catalysis [Transmission Electron Microscopy (TEM) analyses] and the lack of metal leaching in the extracted organic [no palladium detected by Inductively Coupled Plasma‐Atomic Emission Spectrometry (ICP‐AES)]; these systems exhibited enhanced recyclability properties as compared to commercial Pd/C catalyst.

    更新日期:2020-01-26
  • Multilayered Two‐Dimensional V2CTx MXene for Methane Dehydroaromatization
    ChemCatChem (IF 4.495) Pub Date : 2020-01-25
    Raj Thakur; Megan Hoffman; Armin VahidMohammadi; Justin Smith; Mingyang Chi; Bruce Tatarchuk; Majid Beidaghi; Carlos Carrero

    We report a thermally stable multilayered two‐dimensional vanadium carbide (V 2 CT x ) MXenes catalyst for the direct conversion of methane (CH 4 ) into benzene (C 6 H 6 ). The multilayered carbide structure shows state‐of‐the‐art CH 4 conversion 11.8% with a C 6 H 6 formation rate of 1.9 mmol g cat ‐1 h ‐1 (4.84% C 6 H 6 yield) at 700 0 C, which is comparable to the benchmark Mo/ZSM‐5 catalyst. The structure‐activity relationship was explored by numerous characterization techniques including in‐situ/operando Raman‐MS, ex‐situ X‐ray diffraction (XRD), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and ammonia temperature programmed desorption (NH 3 ‐TPD). This work provides a new platform to design and explore multilayered two‐dimensional catalysts demonstrating confinement effect to convert CH 4 into *C 2 H 3 intermediates which further oligomerizes inside multilayered structures producing C 6 H 6 as a final product.

    更新日期:2020-01-26
  • Manipulating the Geometric and Electronic Structures of Manganese Nitrides for Ammonia Synthesis
    ChemCatChem (IF 4.495) Pub Date : 2020-01-25
    Nannan Shan; Chaoran Huang; Robert Tanner Lee; Narges Manavi; Lianbin Xu; Viktor Chikan; Peter Pfromm; Bin Liu

    Manganese (Mn) nitrides are important nitrogen (N) carriers for small‐scale intermittent ammonia (NH 3 ) synthesis. However, only 3~8% of lattice N are converted into NH 3 . In this study, the geometric and electronic structures of well‐defined Mn 4 N and Mn 2 N lattices were altered using transition metal heteroatoms (Cr, Fe, Co, Ni, Mo) to understand the driving force behind lattice N diffusion and extraction. Density Functional Theory (DFT) revealed that the binding of early hydrogenation product (NH) follows a linear relationship with lattice N over a wide range of close‐packed surfaces. But, the binding of NH 2 and NH 3 are more sensitive to the geometric and electronic structures. Further, the chemical bonding can be quantitatively characterized with the covalency derived from Crystal Orbital Hamiltonian Population (COHP). In the Eley Rideal‐Mars van Krevelan pathway, the overall NH 3 formation free energy (ΔE NH3 ) and lattice N diffusion barrier (E a ) are the respective thermodynamic and kinetic determining factors. Aided by a rate‐determining step (RDS) model, Mn 4 N modified with Fe, Co, Ni single‐atom dopants all show enhanced rates for NH 3 formation.

    更新日期:2020-01-26
  • 更新日期:2020-01-24
  • Impact of Al Activators on Structure and Catalytic Performance of Cr Catalysts in Homogeneous Ethylene Oligomerization – A Multitechnique in situ/operando Study
    ChemCatChem (IF 4.495) Pub Date : 2020-01-24
    Reni Grauke; Rahel Schepper; Jabor Rabeah; Roland Schoch; Ursula Bentrup; Matthias Bauer; Angelika Brückner
    更新日期:2020-01-24
  • Kinetic Resolution of Racemic Primary Amines using Geobacillus stearothermophilus Amine Dehydrogenase variant
    ChemCatChem (IF 4.495) Pub Date : 2020-01-24
    Vasilis Tseliou; Tanja Knaus; Jan Vilím; Marcelo F. Masman; Francesco Mutti

    A NADH‐dependent engineered amine dehydrogenase from Geobacillus stearothermophilus (LE‐AmDH‐v1) was applied together with a NADH‐oxidase from Streptococcus mutans (NOx) for the kinetic resolution of pharmaceutically relevant racemic α‐chiral primary amines. The reaction conditions (e.g., pH, temperature, type of buffer) were optimised to yield S‐configured amines with up to >99% ee.

    更新日期:2020-01-24
  • Charge Carriers Cascade in a Ternary TiO2/TiO2/ZnS Heterojunction: A DFT Study
    ChemCatChem (IF 4.495) Pub Date : 2020-01-24
    Giovanni Di Liberto; Sergio Tosoni; Gianfranco Pacchioni

    Composite materials whose band alignment induces a favourable separation of photogenerated electrons and holes often reveal a stronger photocatalytic activity compared to their separate components. As shown by experiments, titania composites display a heterojunction between the anatase (101)‐(001) surfaces, where the former stabilizes electrons and the latter the holes. In principle, an even more efficient carriers separation is achieved if a third component with high hole‐stabilizing capability, ZnS(110), is growth on anatase (001). However, even though this ternary TiO 2 /TiO 2 /ZnS composite material displays good photoactivity, it does not overperform the TiO 2 /TiO 2 one. In this paper an explanation of this evidence is provided by means of periodic hybrid DFT calculations, showing how Coulomb forces play a role against the separation of charge carriers predicted based on the relative energy of the band edges. This highlights the necessity to explicitly account for structural and electronic junction’s effects, as well as charge carriers’ localization.

    更新日期:2020-01-24
  • Effects of Matching Facet Pairs of TiO2 on Photoelectrochemical Water Splitting Behaviors
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Chaiyasit Phawa; Sanchai Prayoonpokarach; Kitiphat Sinthiptharakoon; Pongkarn Chakthranont; Weradesh Sangkhun; Kajornsak Faungnawakij; Teera Butburee

    Engineering crystal facets have been proved as one of the most promising strategies for promoting photocatalytic performance of titanium dioxide (TiO 2 ). The earlier research in this field focused on trying to obtain as high ratio of the high energy {001} facet as possible, while later found that the co‐existence of facets is more beneficial. However, controlling crystal to expose suitable facet pairs and facet ratios remains challenging. In this work, we not only comprehensively match possible low‐index facets such as {101}‐{001} and {010}‐{001} facet pairs, but also systematically tune their ratios. Moreover, these faceted particles can be directly grown onto the transparent conductive substrate, which can be directly used as a photoanode. So, their intrinsic behaviors can be precisely evaluated without interference from other exogenous factors such as binders, additives or assembly skills. Various characterization techniques reveal that both the types of facet pairs and the ratios of facets play crucial roles on photocatalytic behaviors, due to the different electron affinity and dissociative adsorption ability of water molecules on a particular facet. Charge transport and surface chemistry have been thoroughly investigated to identify the underlying mechanism. This work sheds light on considering a suitable match of facet pairs, for optimizing photocatalytic performance for a wide variety of applications.

    更新日期:2020-01-24
  • Hydroconversion of 5‐hydroxymethylfurfural to 2,5‐dimethylfuran and 2,5‐dihydroxymethyltetrahydrofuran over non‐promoted Ni/SBA‐15
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Shuo Chen; Carmen Ciotonea; Karine Vigier; François Jérôme; Robert Wojcieszak; Franck Dumeignil; Eric Marceau; Sébastien Royer

    The selective hydroconversion of 5‐hydroxymethylfurfural (HMF) to biofuels is currently highly sought‐for. While the literature has demonstrated that this reaction is possible on promoted Ni catalysts, we show here that a monometallic, non‐promoted Ni/SBA‐15 catalyst, prepared by incipient wetness impregnation, can convert HMF to 2,5‐dimethylfuran (DMF) and to 2,5‐dimethyltetrahydrofuran (DMTHF) at 180°C, in a consecutive way. Through a control over reaction time, high yields to DMF (71%, at conversion of 93%) or DMTHF (97%, at conversion of 100%) can be achieved. Kinetic modelling suggests a preferential route to DMF via 5‐methylfurfural (MFFR) as intermediate, though the route via 2,5‐bis(hydroxylmethyl)furan (BHMF) is also present. The favoured route in the experimental conditions involves the hydrogenolysis of the hydroxyl group of HMF as first step, followed by the hydrogenation of the aldehyde function, to methylfurfuryl alcohol (MFOL). It is suggested a higher reaction rate of hydrogenation or hydrogenolysis of the side group is linked to the presence of a methyl group in the molecule. No hydrogenation of the furan ring is detected on the intermediates.

    更新日期:2020-01-24
  • Impact of Al Activators on Structure and Catalytic Performance of Cr Catalysts in Homogeneous Ethylene Oligomerization – A Multitechnique in situ/operando Study
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Reni Grauke; Rahel Schepper; Jabor Rabeah; Roland Schoch; Ursula Bentrup; Matthias Bauer; Angelika Brückner
    更新日期:2020-01-23
  • Flavoenzyme‐mediated Regioselective Aromatic Hydroxylation with Coenzyme Biomimetics
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Alice Guarneri; Adrie H. Westphal; Jos Leertouwer; Joy Lunsonga; Maurice C. R. Franssen; Diederik J. Opperman; Frank Hollmann; Willem J. H. van Berkel; Caroline E. Paul
    更新日期:2020-01-23
  • Short‐time Thermal Oxidation of Ultrathin and Broadband Carbon Nitride for Efficient Photocatalytic H2 Generation
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Zhao Mo; Xiaojie She; Zhigang Chen; Fan Xu; Yanhua Song; Xingwang Zhu; Junchao Qian; Huaming Li; Yucheng Lei; Hui Xu
    更新日期:2020-01-23
  • Recent Development on Cp*Ir(III)‐Catalyzed C−H Bond Functionalization
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Xianwei Li; Wensen Ouyang; Jianhong Nie; Shaomin Ji; Qian Chen; Yanping Huo
    更新日期:2020-01-23
  • Defect Engineered Ruthenium MOFs as Versatile Hydrogenation Catalysts
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Roland A. Fischer; Epp Konstantin; Ignacio Luz; Werner R Heinz; Anastasia Rapeyko; Francesc X Llabres i Xamena

    Ruthenium MOF [Ru 3 (BTC) 2 Y y ]·G g (BTC = benzene‐1,3,5‐tricarboxylate ; Y = counter ions = Cl ‐ , OH ‐ , OAc ‐ ; G = guest molecules = HOAc, H 2 O) is modified via a mixed‐linker approach, using mixtures of BTC and pyridine‐3,5‐dicarboxylate (PYDC) linkers, triggering structural defects at the distinct Ru 2 paddlewheel (PW) nodes. This defect‐engineering leads to enhanced catalytic properties due to the formation of partially reduced Ru 2 ‐nodes. Application of a hydrogen pre‐treatment protocol to the Ru‐MOFs, leads to a further boost in catalytic activity. We study the benefits of (1) defect engineering and (2) hydrogen pre‐treatment on the catalytic activity of Ru‐MOFs in the Meerwein‐Ponndorf‐Verley reaction and the isomerization of allylic alcohols to saturated ketones. Simple solvent washing could not avoid catalyst deactivation during recycling for the latter reaction, while hydrogen treatment prior to each catalytic run proved to facilitate materials recyclability with constant activity over five runs.

    更新日期:2020-01-23
  • Heterostructured manganese catalysts for the selective oxidation of 5‐hydroxymethylfurfural to 2, 5‐diformylfuran
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Priyanka Pal; Saravanamurugan Shunmugavel

    A series of manganese oxide catalysts were synthesised in the presence of various precipitants using hydrothermal approach. The manganese oxide synthesised (MnOx‐A‐U) using manganese acetate tetrahydrate and urea as precursor and precipitant, respectively, was found to be composed of heterostructures of manganese, that is, MnCO3, ε‐MnO2 and Mn2O3, and their presence were confirmed by XRD, FTIR and XPS analyses. The catalytic activity of MnOx‐A‐U towards selective oxidation of HMF to DFF in ethanol afforded 92.0% conversion along with 88.0% DFF yield at 120 °C, 30 bar O2, after 4 h of reaction time. Performing HMF oxidation under N2 atmosphere with MnOx‐A‐U yielded only 15.0% DFF, revealing that lattice oxygen played a crucial role in the oxidation process, which was confirmed by subjecting the spent catalyst to XPS analysis. Based on the results obtained from XPS analysis, it was speculated that ε‐MnO2 and MnCO3 could be the active species which could selectively catalyse the reaction. The MnOx‐A‐U catalyst was able to recycle for at least three runs with a small loss of activity due to ε‐MnO2 content decreased.

    更新日期:2020-01-23
  • Unusual Photoactive Water Oxidation Activity of Pt/PtOx Cocatalyst Decorated Crystalline α‐Fe2O3 Nanostructures: Exposed Facets Dependent Reactivity
    ChemCatChem (IF 4.495) Pub Date : 2020-01-23
    Astam Kumar Patra; Vipin Amoli; Anil Kumar Sinha; Dukjoon Kim

    A key challenge remains the preparation of an active and robust water oxidation photocatalyst with abundant earth materials. As a useful to improve photocatalytic efficiency, the development of α‐Fe2O3 nanocrystals with different exposed facets and interfaces has attracted enormous attention. But literature survey shows that α‐Fe2O3 nanomaterials were mainly used in photoelectrochemical cell for water splitting as anode materials. In this work, highly efficient Pt/PtOx cocatalyst decorated α‐Fe2O3 shaped‐photocatalysts were derived as photocatalyst for white light‐induced O2 generation from water without any electric potential. The maximum apparent quantum efficiency of photooxidation reaction was reached 55.33% by Pt/PtOx decorated bitruncated‐dodecahedron shaped α‐Fe2O3 and around 30.5, 2.3, 1.28 times better than the Pt/PtOx decorated nanocuboid, nanorod and bitruncated‐octahedron shape respectively. The Pt/PtOx decorated bitruncated‐dodecahedron shaped α‐Fe2O3 display an unusual photooxidation activity with a high TOF (1.96 x 10‐2 s‐1) due to presence of destabilized and unsaturated Fe centre containing high energy {104} and {100} facets. The present findings clearly demonstrate that the selective O2 evolution from water can possible without any sacrificial agent.

    更新日期:2020-01-23
  • Towards Preparative Chemoenzymatic Oxidative Decarboxylation of Glutamic Acid
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Xiaomin Xu; Andrada But; Ron Wever; Frank Hollmann
    更新日期:2020-01-23
  • Cerium(III) Nitrate Derived CeO2 Support Stabilising PtOx Active Species for Room Temperature CO Oxidation
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Danila Vasilchenko; Tatyana Asanova; Boris Kolesov; Alphiya Tsygankova; Andrey Stadnichenko; Elena Slavinskaya; Evgeny Gerasimov; Kirill Lomachenko; Andrey Boronin; Sergey Korenev
    更新日期:2020-01-23
  • Characterization of Metal‐zeolite Composite Catalysts: Determining the Environment of the Active Phase
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Mitchell Juneau; Renjie Liu; Yikang Peng; Akhilesh Malge; Zhiqiang Ma; Marc D. Porosoff
    更新日期:2020-01-23
  • Use of Immobilized Amine Transaminase from Vibrio fluvialis under Flow Conditions for the Synthesis of (S)‐1‐(5‐Fluoropyrimidin‐2‐yl)‐ethanamine
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Riccardo Semproli; Gianmarco Vaccaro; Erica E. Ferrandi; Marta Vanoni; Teodora Bavaro; Giorgio Marrubini; Francesca Annunziata; Paola Conti; Giovanna Speranza; Daniela Monti; Lucia Tamborini; Daniela Ubiali
    更新日期:2020-01-23
  • 更新日期:2020-01-23
  • Manganese Catalyzed Acceptorless Dehydrogenative Coupling Reactions
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Satyadeep Waiba; Biplab Maji
    更新日期:2020-01-23
  • Enantiotopic Discrimination by Coordination‐Desymmetrized meso‐Ligands
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Yutang Li; Anna Lidskog; Helena Armengol‐Relats; Thanh Huong Pham; Antoine Favraud; Maxime Nicolas; Sami Dawaigher; Zeyun Xiao; Dayou Ma; Emil Lindbäck; Daniel Strand; Kenneth Wärnmark
    更新日期:2020-01-23
  • Phenomenological Rule from Correlations of Conduction/Valence Band Energies and Bandgap Energies in Semiconductor Photocatalysts: Calcium Bismuthates versus Strontium Bismuthates
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    D. S. Shtarev; V. K. Ryabchuk; A. V. Rudakova; A. V. Shtareva; M. S. Molokeev; E. A. Kirichenko; N. Serpone
    更新日期:2020-01-23
  • Three‐Enzyme Phosphorylase Cascade Immobilized on Solid Support for Biocatalytic Synthesis of Cello−oligosaccharides
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Chao Zhong; Božidar Duić; Juan M. Bolivar; Bernd Nidetzky
    更新日期:2020-01-23
  • Morphology Evolution of Hcp Cobalt Nanoparticles Induced by Ru Promoter
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Lili Liu; Chuan Qin; Mengting Yu; Qiang Wang; Jungang Wang; Bo Hou; Litao Jia; Debao Li

    The modification of the equilibrium morphology to expose active facets of cobalt nanoparticles is essential for tailoring and controlling its catalytic performance. Periodic density functional theory (DFT) was applied to systematically investigate the structure and stability of exposed facets of hcp Co nanoparticles induced by Ru promoter in order to clarify the facet‐dependent equilibrium morphology of hcp Co nanoparticles stabilized by Ru promoter. The adsorption and migration of Ru atom can give rise to the change of the surface energy of exposed facets, thus affecting the equilibrium morphology of the hcp Co nanoparticles. Selectively exposed the high Miller index facets, such as Co(10‐12), Co(11‐20) and Co(11‐21) surfaces, can be tuned by adding Ru promoter. Our theoretical calculation results show that Co(11‐21) becomes the predominantly exposed facet accompanied with the decrease of exposed Co(10‐10) and Co(10‐11) with the increase of Ru loading. Further experimental studies suggest that the area of selectively exposed the Co(10‐11) surface for uniform Co nanoplates loaded with 3.0 wt% Ru will be reduced, which is in agreement with the theoretical predicted result. This work is helpful to design the desired Co‐based FTS catalysts rationally with well‐controlled surface structure.

    更新日期:2020-01-23
  • Enantioselective Bioamination of Aromatic Alkanes Using Ammonia: A Multienzymatic Cascade Approach
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Hui Wang; Yu-Cong Zheng; Fei-Fei Chen; Jian-He Xu; Hui-Lei Yu

    Chiral amines are common drug building blocks and important active pharmaceutical ingredients. Preparing these functionalized compounds from simple materials, such as alkanes, is of great interest. We recently developed an artificial bioamination cascade for the C–H amination of cyclic alkanes by combining P450 monooxygenase, alcohol dehydrogenase, and amine dehydrogenase. Herein, this system has been extended to the synthesis of chiral aromatic amines. In the first hydroxylation step, process optimization increased the conversion to 77%. Two stereoselective ly complementary alcohol dehydrogenases and an amine dehydrogenase were selected for the bioconversion of aromatic hydrocarbons to amines. The amination reaction was optimized with respect to cofactor addition and enzyme dosage. Isopropanol was added to decrease ketone intermediate accumulation in the amination step, which further enhanced the overall conversion. This cascade system converted a panel of hydrocarbon substrates into the corresponding amines with excellent optical purity (>99% ee ) and moderate conversion ratios (13–53%).

    更新日期:2020-01-23
  • Selective oxyfunctionalisation reactions driven by sulfite oxidase‐catalysed in situ generation of H2O2
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Morten Martinus Cornelis Harald van Schie; Alexander T. Kaczmarek; Florian Tieves; Patricia Gómez de Santos; Caroline E. Paul; Isabel W.C.E. Arends; Miguel Alcalde; Günter Schwarz; Frank Hollmann

    H 2 O 2 can be accepted by several peroxygenases as a clean oxidant, able to supply both the necessary electrons and oxygen moiety at the same time. The biocatalysts, in turn, are able to catalyze an array of interesting oxygen insertion reactions at enantio‐ and region‐selectivities hard to attain with classical chemical methods. The sensitivity of most peroxygenases towards H 2 O 2 , however, requires this oxidant to be generated in situ . Here, we suggest the application of (modified) sulfite oxidases to couple the oxidation of sulfites to the reduction of oxygen. This enables us to use calcium sulfite, an industrial waste product from scrubbing flue gasses, as an electron donor to reduce oxygen. This will supply the required peroxide in a controlled manner and enables us to perform these challenging reactions at the expense of simple salts.

    更新日期:2020-01-23
  • Evans‐Chan‐Lam‐Type Azidation and One‐Pot CuAAC under CuI‐Zeolite Catalysis
    ChemCatChem (IF 4.495) Pub Date : 2020-01-22
    Arnaud CLERC; Valérie BENETEAU; Patrick PALE; Stefan Chassaing

    The copper(I)‐exchanged zeolite Cu I ‐USY proved to efficiently catalyze the direct azidation of arylboronic acids with sodium azide under simple and practical conditions, namely at room temperature under air with methanol as solvent and without any additive. This easy‐to‐prepare and cheap catalytic material has been demonstrated to be recyclable and the mild azidation conditions further showed good functional‐group tolerance, leading to a variety of substituted (hetero)aryl azides (18 examples). Interestingly, the azidation reaction has been successfully coupled to a CuAAC reaction, thus allowing access to triazoles from arylboronic acids via a one‐pot Cu I ‐catalyzed process.

    更新日期:2020-01-23
  • Yolk‐Shell‐Structured CuO‐ZnO‐In2O3 trimetallic oxide mesocrystal microspheres as an efficient catalyst for trichlorosilane production
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Fabing Su; Xin Li; Yongjun Ji; Jing Li; Yu Zhang; Hezhi Liu; Qiongguang Li; Lihua Jia; Xiangfeng Guo; Ziyi Zhong

    Trichlorosilane (TCS), the primary chemical feedstock for production of high‐purity Si used in Si‐based solar cells, is currently manufactured industrially via a non‐catalytic hydrochlorination of metallurgical Si. This process generates a huge amount of undesirable silicon tetrachloride (STC) byproduct. Here we report the synthesis of yolk‐shell‐structured CuO‐ZnO‐In2O3 trimetallic oxide mesocrystal microspheres that can be employed as an efficient catalyst to produce TCS catalytically. The CuO‐ZnO‐In2O3 microspheres with multiple hetero‐interfaces were prepared using a facile solvothermal reaction followed by calcination. We found that differing from a single CuO mesocrystal, the electronic density on Cu atoms in the CuO phase within CuO‐ZnO and CuO‐ZnO‐In2O3 can be well‐tuned via controlling the introduced composition. When used as a catalyst for Si hydrochlorination reaction to produce TCS, CuO‐ZnO‐In2O3 presents excellent catalytic performance with much high Si conversion and TCS selectivity. Under the same reaction condition, the TCS yield increased 13 times compared with the catalyst‐free process. This work not only demonstrates the high possibility to realize the catalytic manufacture of TCS with less STC but also provides an approach to the facile synthesis of multi‐component mesocrystal materials with a specific structure.

    更新日期:2020-01-23
  • 更新日期:2020-01-22
  • The Pivotal Role of Boron in Improving the Azo Dye Degradation of Glassy Fe‐based Catalysts
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Shenghui Xie; Yuelin Xie; Jamie J. Kruzic; Kunming Gu; Haipeng Yang; Yuanming Deng; Xierong Zeng
    更新日期:2020-01-22
  • Recent Developments in the Modelling of Heterogeneous Catalysts for CO2 Conversion to Chemicals
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Natalia Podrojková; Victor Sans; Andrej Oriňak; Renata Oriňaková
    更新日期:2020-01-22
  • A Heterogeneous Recyclable Rhodium‐based Catalyst for the Reduction of Pyridine Dinucleotides and Flavins
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Yifan Deng; Mateusz Odziomek; Clement Sanchez; Olivier Back; Victor Mougel; Marc Fontecave
    更新日期:2020-01-22
  • Catalytic Steam Reforming of Natural Gas over a New Ni Exsolved Ruddlesden‐Popper Manganite in SOFC Anode Conditions
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Sebastián Vecino‐Mantilla; Erika Quintero; Camilo Fonseca; Gilles H. Gauthier; Paola Gauthier‐Maradei
    更新日期:2020-01-22
  • Immobilised Enzymes for Sesquiterpene Synthesis in Batch and Flow Systems
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Donya Valikhani; Prabhakar L Srivastava; Rudolf K Allemann; Thomas Wirth

    Sesquiterpene synthases catalyse the bioconversion of farnesyl diphosphate into sesquiterpenes. The immobilisation of sesquiterpene synthases on controlled porosity glass through metal‐ion affinity binding is reported. The immobilised sesquiterpene synthases were able to maintain 50% catalytic activity for at least 50 cycles under continuous flow conditions.

    更新日期:2020-01-22
  • Structure and quantification of edge sites of WS2/Al2O3 catalysts coupling IR/CO spectroscopy and DFT calculations
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Francoise Maugé; Jean Francois PAUL; Laetitia OLIVIERO; Luz ZAVALA SANCHEZ; Ibrahim Khalil

    IR spectroscopy of CO adsorption (IR/CO) and Density Functional Theory (DFT) calculations on sulfide W/Al 2 O 3 catalyst were investigated for an insight into the sulfide edge sites. Parallel between experimental and theoretical results allow to assign the ν (CO) bands at 2121 and 2066 cm ‐1 to CO adsorption on M‐ and S‐edge sites of WS 2 phase, respectively. Through a careful analysis of CO spectra on well‐selected W catalysts, the molar attenuation coefficients for CO adsorbed on the two exposed edges could be determined. This allowed the morphology of WS 2 slabs to be calculated. This work shows that increasing the W loading (6‐20 wt% W) changes the slab morphology from an almost pure triangle exhibiting mostly M‐edge to a truncated triangle. On W as well as on Mo sulfide catalysts, IR spectroscopy and DFT calculation show that CO adsorption allows to account for M‐ and S‐edge sites, and thus of the morphology of sulfide slabs. It was shown that increasing the W loading shifts the slab morphology from a triangle exposing predominantly M‐edge towards a more hexagonal shape. For close to monolayer coverage of alumina, Mo and W sulfide slabs present similar shape i.e. truncated triangle. However, edge sites of WS 2 slabs clearly exhibit greater stability under H 2 atmosphere than Mo sulfided ones.

    更新日期:2020-01-22
  • Selective hydrogenation of xylose to xylitol over Co/SiO2 catalysts
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Maïté Audemar; Wahiba Ramdani; Tang Junhui; Andreea Raluca Ifrim; Adrian Ungureanu; François Jérôme; Sébastien Royer; Karine De Oliveira Vigier

    Xylose can be selectively converted to xylitol in water, with an optimized yield of 98%, in the presence of a simple silica supported monometallic cobalt ‐ Co/SiO 2 ‐ catalyst. This catalyst displays initial outstanding catalytic properties in a proper solvent, the best results being obtained in pure water. Recyclability studies show a moderate deactivation of the catalyst, while selectivity to xylitol remains almost unchanged after 4 cycles, confirming that this catalyst formulation is very promising for the xylitol production process.

    更新日期:2020-01-22
  • Carbon Anchored Epitaxially Grown Nickel Cobalt‐Based Carbonate Hydroxide for Urea Electrooxidation Reaction with a High Activity and Durability
    ChemCatChem (IF 4.495) Pub Date : 2020-01-21
    Diab Khalafallah; Ouyang Chong; Mingjia Zhi; Zhanglian Hong

    Urea has shown a potential importance as a possible alternative hydrogen‐storage source for low‐temperature fuel cells. Besides, the electrooxidation of urea provides an efficient solution for the disposal of wastewater in the agricultural industry, but the state‐of‐the art urea electrocatalysis suffers from the associated sluggish kinetics. In this study, we fabricated unique vertically aligned nanorod arrays‐like carbon anchored nickel‐cobalt carbonate hydroxides (C―NiCo CHs) without agglomeration through a mass scale one‐step hydrothermal approach for electrocatalytic oxidation of urea in an alkaline environment. The composite affords a high specific surface area of 162.55 m2 g−1 with distinctive porous features, suggesting a large surface exposure and sufficient electrolyte accessibility during chemical reactions. The catalyst exhibits an outstanding electrocatalytic activity towards urea electrooxidation with a high current density and an outstanding durability benefiting from the tuned electric conductivity. Impressively, the hybrid shows a greatly improved catalytic performance at higher KOH moieties with a much‐enhanced peak current and a negatively shifted onset voltage, which can be interpreted by the intensive Ni activation processes caused by the densely formed OH― ions. These findings signify that the well‐developed nanoarchitecture of C―NiCo CHs hybrid could pave the way to rationally fabricate highly active electrocatalysts for urea electrocatalysis.

    更新日期:2020-01-22
  • Oriented isomorphous substitution: an efficient and alternative route to fabricate the Zn rich phase pure (Cu1‐x,Znx)2(OH)2CO3 precursor catalyst for methanol synthesis
    ChemCatChem (IF 4.495) Pub Date : 2020-01-20
    Huayan Zheng; Nilesh Narkhede; Huacheng Zhang; Zhong Li

    A new methodology has been demonstrated for the synthesis of series of phase pure (Cu 1‐ x ,Zn x ) 2 (OH) 2 CO 3 precursors by isomorphous substitution of Zn 2+ in the malachite structure. By following the present protocol it was possible to synthesize the pure phase (Cu 1‐ x ,Zn x ) 2 (OH) 2 CO 3 with substitution level as high as x =0.5 which is better than the maximum possible value achieved by coprecipitation method, i.e. x =0.31. The isomorphous substitution by Zn 2+ leads to the change in the morphology of malachite crystals from flake‐like to regular needle‐like shape with high Zn dispersion. The activity of the calcined catalysts was increased by ~1.5‐1.7 fold for the hydrogenation of syngas to methanol as compared with those prepared from the traditional coprecipitation route. The synergy between Cu and ZnO was further demonstrated quantitatively by characterization of the catalysts treated with syngas at 250 o C.

    更新日期:2020-01-22
  • 更新日期:2020-01-21
  • Comprehensively probing the contribution of site activity and population of active site toward heterogeneous electrocatalysis
    ChemCatChem (IF 4.495) Pub Date : 2020-01-20
    Hsiao-Chien Chen; Tai-Lung Chen; Sheng-Chih Lin; Chia-Shuo Hsu; Ting‐Shan Chan; Mei-Yi Liao; Hao Ming Chen

    Due to the enormous demand for clean energy generation and for efficient energy storage, developing green and storable energy has become an urgent task. This subject, thus, stimulates studies on the improvement of new electrocatalysts. Specifically, through improving the population of active site and/or the activity of individual sites, the performance of the catalysts can be significantly improved. However, clarifying the contribution of these two factors is still ambiguous and must be done with great care. To allow researchers in related fields to present their findings objectively, having a clear insight into the electrocatalytic activity is indispensable. In this study, a series of cobalt‐based pre‐electrocatalysts are taken as an example to examine their corresponding oxygen evolution reaction (OER) behaviors. Wherein, the three important metrics ‒ electrochemical active surface area (ECSA)/roughness factor (RF), Tafel slope, and turnover frequency (TOF) ‒ are used to profile the population of active sites of electrocatalysts and the activity of related individual sites. The results indicate the correction of OER behavior by ECSA/RF manifests the more accurate identification of OER activity. Meanwhile, the timing to obtain RF/ECSA significantly influence such an evaluation. Altogether, a fair benchmarking is proposed for the comparison between the activities of electrocatalysts.

    更新日期:2020-01-21
  • FeCoNi ternary spinel oxides nanosheets as high performance water oxidation electrocatalyst
    ChemCatChem (IF 4.495) Pub Date : 2020-01-20
    Qingquan Kong; Weijing Bai; Fangzheng Bai; Xuguang An; Wei Feng; Fengling Zhou; Qiuyue Chen; Qingyuan Wang; Chenghua Sun

    FeCoNi spinel oxides nanosheets array directly supported on the Ni foam substrate were prepared via a facile wet chemical method with 2‐methylimidazole as a structure directing agent and subsequently annealing. The as‐prepared 0.1Fe‐CoNiO/NF offers high intrinsic catalytic activity, high surface area and good conductivity, resulting in enhanced activity for the oxygen evolution reaction (OER) in the alkaline solution. It demonstrates an ultralow overpotentials of 240 mV at 10 mA cm ‐2 and a small Tafel slope of 36.8 mV dec ‐1 , with attractive durability during long‐term operation in 1 M KOH solution.

    更新日期:2020-01-21
  • Embedding Sulfur Atoms in Decahedron Bismuth Vanadate Crystal with Soft Chemical Approach for Expanding Light Absorption
    ChemCatChem (IF 4.495) Pub Date : 2020-01-17
    Yue Zhao; Taifeng Liu; Ruotian Chen; Bin Zeng; Xiaoping Tao; Jianming Li; Xu Jin; Rengui Li; Can Li

    Bandgap engineering of semiconductors attracts great attentions in the field of photocatalysis to enhance the conversion efficiency of semiconductors. Introducing impurity atoms, such as nitrogen, sulfur and metal atoms, into the crystal lattice of semiconductors is one of the commonly used methods to broaden the light absorption range. However, traditional methods to embed impurity atoms require harsh conditions like high temperatures, which will destroy the morphology‐tailored structure of semiconductors in many cases. Herein, we demonstrated a soft chemical approach, hydrothermal method, to expanding light absorption range by introducing sulfur atoms in typical semiconductor bismuth vanadate (BiVO 4 ). After embedding sulfur atoms, the light absorption edge of BiVO 4 crystals can be obviously expanded from 530 nm to longer than 650 nm, while, the decahedron morphology with exposed {010} and {110} facets of BiVO 4 crystals was still well‐maintained. The sulfur‐embedded BiVO 4 crystals show photocurrent response even under the wavelengths longer than 550 nm and also exhibit an evident enhancement than pristine BiVO 4 in photoelectrochemical performances under visible light. Our work offers a strategy for manipulating the band structures of semiconductors for applications in solar energy conversion.

    更新日期:2020-01-21
  • 更新日期:2020-01-17
  • 3D‐Graphene Decorated with g‐C3N4/Cu3P Composite: A Noble Metal‐free Bifunctional Electrocatalyst for Overall Water Splitting
    ChemCatChem (IF 4.495) Pub Date : 2020-01-17
    Sk. Riyajuddin; S. K. Tarik Aziz; Sushil Kumar; Gilbert D. Nessim; Kaushik Ghosh
    更新日期:2020-01-17
  • A Novel Earth‐Abundant W‐WC Heterojunction as Efficient Co‐Catalyst for Enhanced Photocatalytic H2 Evolution
    ChemCatChem (IF 4.495) Pub Date : 2020-01-17
    Baojun Ma; Sipeng Zhang; Wei Wang; Li Feng; Ruisheng Zhang; Keying Lin; Dekang Li; Haijuan Zhan; Xu Yang
    更新日期:2020-01-17
  • Catalytic Transfer Hydrogenation of Furfural over Co3O4−Al2O3 Hydrotalcite‐derived Catalyst
    ChemCatChem (IF 4.495) Pub Date : 2020-01-17
    Ruben Ramos; Andreia F. Peixoto; Blanca I. Arias‐Serrano; O. Salomé G. P. Soares; Manuel F. R. Pereira; David Kubička; Cristina Freire
    更新日期:2020-01-17
  • Nitrogen‐Doped Carbons with Hierarchical Porosity via Chemical Blowing Towards Long‐Lived Metal‐Free Catalysts for Acetylene Hydrochlorination
    ChemCatChem (IF 4.495) Pub Date : 2020-01-17
    Selina K. Kaiser; Kyung Seob Song; Sharon Mitchell; Ali Coskun; Javier Pérez‐Ramírez
    更新日期:2020-01-17
  • 更新日期:2020-01-17
  • 更新日期:2020-01-17
  • Nanomesh‐Structured Graphitic Carbon Nitride Polymer for Effective Capture and Photocatalytic Elimination of Bacteria
    ChemCatChem (IF 4.495) Pub Date : 2020-01-16
    Huifan Li; Mengna Ding; Liulin Luo; Guoxiang Yang; Fengyan Shi; Yuning Huo
    更新日期:2020-01-17
  • New Insights on the Dynamic Role of the Protecting Agent on the Reactivity of Supported Gold Nanoparticles
    ChemCatChem (IF 4.495) Pub Date : 2020-01-16
    Giorgio Grillo; Federica Menegazzo; Silvia Tabasso; Michela Signoretto; Maela Manzoli; Giancarlo Cravotto
    更新日期:2020-01-17
  • Functionalized Iron Hydroxyapatite as Eco‐friendly Catalyst for NH3‐SCR Reaction: Activity and Role of Iron Speciation on the Surface
    ChemCatChem (IF 4.495) Pub Date : 2020-01-16
    Sebastiano Campisi; Melissa G. Galloni; Sergio G. Marchetti; Aline Auroux; Georgeta Postole; Antonella Gervasini
    更新日期:2020-01-17
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