281,054 research outputs found

    CO preferential oxidation in a novel Au@ZrO₂ flow-through catalytic membrane reactor with high stability and efficiency

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    CO preferential oxidation (CO-PROX) achieves much interest as a strategy to remove trace CO in reformed gases for hydrogen utilization. Herein, we reported a novel Au@ZrO₂ catalytic membrane reactor by embedding gold nano-particles in ZrO₂ hollow fiber membrane for CO-PROX. The flow-through catalytic membrane exhibited high catalytic activity and oxygen selectivity, which gave a turnover frequency of 4.73 s⁻¹ at 60 °C, 2–3 times higher than conventional catalyst pellets. CO conversion of >95% was achieved over the catalytic membrane, which maintained great operational stability during 500-h operation even CO₂ and H₂O were added in the feed stream. The excellent catalytic performance of the flow-through catalytic membrane makes gold catalyst possible for practical application in the removal of CO from hydrogen

    Continuous catalytic decomposition of methane

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    Continuous catalytic decomposition of methane and application to space life support syste

    Structuring Pt/CeO2/Al2O3 WGS catalyst: Introduction of buffer layer

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    This work is devoted to the development of novel structured catalytic system for WGS reaction. The new concept is related to the presence of a pre-catalytic “buffer” layer formed by WGS-inert oxide, i.e. not involved in CO conversion, but able to increase the number of participating sites in water dissociation step during the reaction. The performance of the proposed systems appears to depend strongly on the stream composition, being its effect beneficial in highly reducing atmospheres making it ideal for clean-up application. An increment of the partial kinetic order for water species is observed and reveals the key role of the water activation for superior catalytic behavior.Junta de Andalucía TEP-819

    Structural, electrical and catalytic properties of ion-implanted oxides

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    The potential application of ion implantation to modify the surfaces of ceramic materials is discussed. Changes in the chemical composition and microstructure result in important variations of the electrical and catalytic properties of oxides

    Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

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    Within the “Compartmentalised Smart Factory” approach of the ONE-FLOW project the implementation of different catalysts in “compartments” provided by Pickering emulsions and their application in continuous flow is targeted. We present here the development of heterogeneous Pd-catalysts that are ready to be used in combination with biocatalysts for catalytic cascade syntheses of active pharmaceutical ingredients (APIs). In particular, we focus on the application of the catalytic systems for Suzuki-Miyaura cross coupling reactions, which is the key step in the syntheses of the targeted APIs valsartan and sacubitril. An immobilised enzyme will accomplish the final product formation via hydrolysis. In order to create large interfacial area for the catalytic reactions and to keep the reagents separated until required, the catalyst particles are used to stabilise Pickering emulsions of oil and water. A set of Ce-Sn-Pd-oxides with the molecular formula Ce0.99-xSnxPd0.01O2-(x= 0-0.99) has been prepared utilising a simple single-step solution combustion method. The high applicability of the catalysts for different functional groups and their minimal leaching behaviour is demonstrated with various Suzuki-Miyaura cross coupling reactions in batch as well as in continuous flow employing the so-called “Plug & Play reactor”. Finally, we demonstrate the use of these particles as the sole emulsifier of oil + water emulsions for a range of oils

    Infra-red studies of the surface acidity of oxides and zeolites using adsorbed probe molecular

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    The use of infrared spectroscopy to probe the surface acidity of oxides and molecular sieves is reviewed. The experimental requirements and the type and nature of probe molecules available are also discussed. Special emphasis is given to the criteria that have to be met to arrive at a characterization of the solid that is useful for its catalytic application

    MACiE: a database of enzyme reaction mechanisms.

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    SUMMARY: MACiE (mechanism, annotation and classification in enzymes) is a publicly available web-based database, held in CMLReact (an XML application), that aims to help our understanding of the evolution of enzyme catalytic mechanisms and also to create a classification system which reflects the actual chemical mechanism (catalytic steps) of an enzyme reaction, not only the overall reaction. AVAILABILITY: http://www-mitchell.ch.cam.ac.uk/macie/.EPSRC (G.L.H. and J.B.O.M.), the BBSRC (G.J.B. and J.M.T.—CASE studentship in association with Roche Products Ltd; N.M.O.B. and J.B.O.M.—grant BB/C51320X/1), the Chilean Government’s Ministerio de Planificacio´n y Cooperacio´n and Cambridge Overseas Trust (D.E.A.) for funding and Unilever for supporting the Centre for Molecular Science Informatics.application note restricted to 2 printed pages web site: http://www-mitchell.ch.cam.ac.uk/macie

    Graphene-Based Nanostructures in Electrocatalytic Oxygen Reduction

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    Application of graphene-type materials in electrocatalysis is a topic of growing scientific and technological interest. A tremendous amount of research has been carried out in the field of oxygen electroreduction, particularly with respect to potential applications in the fuel cell research also with use of graphene-type catalytic components. This work addresses fundamental aspects and potential applications of graphene structures in the oxygen reduction electrocatalysis. Special attention will be paid to creation of catalytically active sites by using non-metallic heteroatoms as dopants, formation of hierarchical nanostructured electrocatalysts, their long-term stability, and application as supports for dispersed metals (activating interactions)

    Methane-Carbon Dioxide: Conversions to Syngas and Hydrocarbons

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    This monograph describes the new innovation that has recently been developed for the CH4-CO2 conversions process. Optimization of CO2 reforming of methane to synthesis gas with the help of experimental design, empirical modeling and ANN modeling are developed for CORM in presence of oxygen. An overview on dynamic equilibrium analysis has shown that an increase of sweep factors induced more significant enhancement hydrogen permeation than permselective area. The NiO/CeO2 catalyst showed potential as catalyst for the CORM. The application of a hybrid catalytic DBD plasma reactor has the potential for the co-generation of C2+ hydrocarbons and synthesis gases from methane and carbon dioxide. Carbon dioxide as co-feed has important effects on the carbon suppression. It can be concluded that three factors, i.e. CH4/CO2 feed ratio, total feed flow rate, and discharge voltage, in the DBD plasma reactor system have significant effects on the reactor performance. The hybrid catalytic DBD plasma reactor is more suitable for CO2 OCM process than the conventional catalytic reactor over CaO-MnO/CeO2 catalyst. Further innovation and improvement of current research on CH4 and CO2 are required to increase conversion and selectivity and to commercialize the process
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