8,823 research outputs found

    SAMPLE INTRODUCTION AND INSTRUMENTATION IN PLASMA SPECTROMETRY

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    Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9N

    The Effect of Co-feeding Methyl Acetate on the H-ZSM5 Catalysed Methanol-to-Hydrocarbons Reaction

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    Funding Information: Johnson Matthey plc and the EPSRC are thanked for postgraduate student support (A.P.H., A.Z.) via the Industrial CASE scheme (EP/P510506/1). Johnson Matthey plc is additionally thanked for provision of the ZSM-5 catalyst. The Science and Technology Facilities Council is thanked for the provision of neutron beam time (RB1820116, https://doi.org/10.5286/isis.e.97999822 ). The resources and support provided by the UK Catalysis Hub via Membership of the UK Catalysis Hub Consortium and funded by EPSRC (Grants EP/K014706/1, EP/K014668/1, EP/ K014854/1, EP/K014714/1, and EP/M013219/1) are gratefully acknowledged.Peer reviewedPublisher PD

    Neutron spectroscopy studies of methanol to hydrocarbons catalysis over ZSM-5

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    Acknowledgements Johnson Matthey plc and the EPSRC are thanked for postgraduate student support (A.P.H., A.Z.) via the Industrial CASE scheme (EP/P510506/1 and EP/N509176/1 respectively). Johnson Matthey plc is additionally thanked for provision of the ZSM-5 catalyst, plus some characterisation information. The STFC Rutherford Appleton Laboratory is thanked for access to the neutron beam facilities. The UK Catalysis Hub is thanked for resources, support and access to the Research Complex at Harwell which is provided via our membership of the UK Catalysis Hub Consortium and funded by UK Engineering and Physical Sciences Research Council (grants EP/K014706/1, EP/K014668/1, EP/K014854/1, EP/K014714/1 and EP/M013219/1).Peer reviewedPublisher PD

    New Spectroscopic Insight into the Deactivation of a ZSM-5 Methanol-to-Hydrocarbons Catalyst

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    Funding Information: Johnson Matthey plc. is thanked for supplying the ZSM‐5 zeolite and for financial support through the provision of industrial CASE studentships in partnership with the EPSRC (APH (EP/P510506/1), AZ (EP/N509176/1)). Experiments at the ISIS Neutron and Muon Source were made possible by a beam time allocation from the Science and Technologies Facilities Council. The resources and support provided by the UK Catalysis Hub membership of the UK Catalysis Hub consortium and funded by EPSRC grants EP/R026815/1 and EP/R026939/1 are gratefully acknowledged. This research has been performed with the use of facilities and equipment at the Research Complex at Harwell; the authors are grateful to the Research Complex for this access and support. Dr Andrea Sauerwein and Dr Jonathan Bradley (Johnson Matthey) are thanked for their help in acquiring the Si and Al NMR spectra using the Bruker Avance Neo spectrometer.Peer reviewedPublisher PD

    Performance evaluation of diesel particulate filters on heavy-duty vehicles

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    Diesel particulate filters, or DPFs, are exhaust aftertreatment devices used to reduce exhaust emissions from diesel powered vehicles. Typical designs have a wall flow filter element downstream of an oxidation catalyst, which oxidizes a portion of the NO present in the exhaust stream to form NO2. The resulting NO2 aides in the combustion of the soot collected in the wall flow filter element allowing for the complete breakdown of the soot within typical diesel exhaust temperatures, thus limiting the required maintenance on the filter elements to the removal of non-combustible ash.;Three aspects of DPF performance were investigated: cold start performance, filter durability, and general efficiencies. The cold start performance evaluation determined that the filter elements trapped particulate matter prior to the DPF light-off temperature being reached, however there was no significant impact on white smoke emissions at any temperature range. The DPF light-off temperature was determined to be between 330°F and 450°F for the Engelhard DPX and between 375°F and 450°F for the Johnson-Matthey CRT.;The filter durability study showed a slight degeneration of DPF performance as age and accumulated mileage increased. However, a definitive DPF life span could not be determined due to inconsistencies in the data from one testing round to the next.;In the general efficiencies evaluation, CO emissions were reduced by greater than 84% for both DPF styles tested. HC emissions were reduced by 76% with the Engelhard DPX and by 81% with the Johnson-Matthey CRT. PM emissions were reduced by 94% and 82% by the Engelhard DPX and the Johnson-Matthey CRT respectively. No significant changes were recorded for total NOx (NO + NO2) or CO2 emissions

    Chemically Ordered Pt–Co–Cu/C as Excellent Electrochemical Catalyst for Oxygen Reduction Reaction

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    This paper reveals the ordered structure and composition effect to electrochemical catalytic activity towards oxygen reduction reaction (ORR) of ternary metallic Pt–Co–Cu/C catalysts. Bimetallic Pt-Co alloy nanoparticles (NPs) represent an emerging class of electrocatalysts for ORR, but practical applications, e.g. in fuel cells, have been hindered by low catalytic performances owning to crystal phase and atomic composition. Cu is introduced into Pt-Co/C lattices to form PtCoxCu1−x/C (x = 0.25, 0.5 and 0.75) ternary-face-centered tetragonal (fct) ordered ternary metallic NPs. The chemically ordered Pt–Co–Cu/C catalysts exhibit excellent performance of 1.31 A mg−1 Pt in mass activity and 0.59 A cm−2 Pt in specific activity which are significantly higher than Pt-Co/C and commercial Johnson Matthey (JM) Pt/C catalysts, because of the ordered crystal phase and composition control modified the Pt-Pt atoms distance and the surface electronic properties. The presence of Cu improves the surface electronic structure, as well as enhances the stability of catalysts

    Determinación espectroquímica de impurezas en plata

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    Con el fin de verificar el grado de pureza de la plata empleada principalmente para la fabricación de fusibles, se ha aplicado el análisis espectroquímico por su gran sensibilidad y rapidez. Debido a la gran variedad en el diámetro de los alambres y ante la imposibilidad de disponer de los patrones standard para cada medida, fue necesario disolver la muestra y realizar el análisis sobre las sales (nitratos). Las muestras standard se prepararon por el mismo procedimiento, empleando sustancias de pureza espectroscópica (Johnson Matthey). Esta técnica de análisis nos permite determinar once elementos (Cu, Cd, Pb, Ni, Sn, Al, Zn, Pt, Pd, Ir, Au). Se utilizo un espectrógrafo Z-3 (Jobin-Yvon), fuente de excitación G.M.60 (de Durr) y densitómetro 21-051 (Jarrell-Ash).Because of its great sensitivity and time-saving characteristics spectrochemical analysis has "been applied to the purity control of silver to he used mainly in fuse manufacture. As wires differ widely in their diameters and it is almost impossible to obtain standards por each size, it was necessary to disolve the sample and analize the resulting salts (nitrates). Standard samples were prepared making use of the procedure on spectroscopically pure materials (Johnson Matthey). This analytical technique allows the determination of eleven elements, i.e. Cu, Cd, Pb, Ni, Sn, Al, Zn, Pt, Pd, Ir, Au. Instrumentation used includes Jobin-Yvon Z-3 spectrograph, Durr G.M.60 excitation source and Jarrell-Ash,model 21-051 densitometer

    Counting the Acid Sites in a Commercial ZSM-5 Zeolite Catalyst

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    This work was funded by Johnson Matthey plc. through the provision of industrial CASE studentships in partnership with the EPSRC (AZ (EP/N509176/1), APH (EP/P510506/1)). Experiments at the ISIS Neutron and Muon Source were made possible by beam time allocations from the Science and Technologies Facilities Council.45,46 Resources and support were provided by the UK Catalysis Hub via membership of the UK Catalysis Hub consortium and funded by EPSRC grants EP/R026815/1 and EP/R026939/1Peer reviewedPublisher PD
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