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  • 101.
    Sá, Jacinto
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Polish Acad Sci, Inst Phys Chem, Ul Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Medlin, J. Will
    Univ Colorado, Dept Chem & Biol Engn, JSCBB D125 3415 Colorado Ave, Boulder, CO 80303 USA.
    On-the-fly Catalyst Modification: Strategy to Improve Catalytic Processes Selectivity and Understanding2019Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 11, nr 15, s. 3355-3365Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Hydrogenation is a quintessential process to the chemical industry. It is heavily involved in organic synthesis and fuel production, among other processes. Preferentially the reactions are carried out with heterogeneous catalysts and when possible in flow mode. Herein, we provide a retrospective on selective surface modification of catalysts for improved selectivity and understanding of catalytic reactivity. In addition, we provide a prospectus for an emerging strategy of carrying out surface modification on-the-fly to produce novel catalysts in a fast and reproducible way and to understand catalytic phenomena.

  • 102. Sá, Jacinto
    et al.
    Szlachetko, Jakub
    Sikora, Marcin
    Kavčič, Matjaž
    Safonova, Olga V
    Nachtegaal, Maarten
    Magnetic manipulation of molecules on a non-magnetic catalytic surface.2013Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 5, nr 18, s. 8462-5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Non-magnetic Pt catalysts, supported on carbon coated magnetic Co nanoparticles, changed catalytic performance in the presence of an external magnetic field. This behavior relates to an electronic change of Pt induced by a localized magnetic field, which modifies the CO adsorption geometry. In situ resonant inelastic X-ray scattering (RIXS) experiments and theory reveal the change of atop CO adsorption geometry on the Pt catalyst to bridged geometry under an external magnetic field. This observation opens the possibility of catalytic control by means of an external magnetic field.

  • 103.
    Tang, Yingying
    et al.
    Tech Univ Denmark, Dept Chem, DK-2800 Kongens Lyngby, Denmark.
    Cao, Xianyi
    Tech Univ Denmark, Dept Chem, DK-2800 Kongens Lyngby, Denmark.
    Honarfar, Alireza
    Lund Univ, Dept Chem Phys & NanoLund, Box 124, S-22100 Lund, Sweden.
    Abdellah, Mohamed
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. South Valley Univ, Qena Fac Sci, Dept Chem, Qena 83523, Egypt.
    Chen, Chaoyu
    LOrme Merisiers, Synchrotron SOLEIL, St Aubin BP 48, F-91192 Gif Sur Yvette, France.
    Avila, Jose
    LOrme Merisiers, Synchrotron SOLEIL, St Aubin BP 48, F-91192 Gif Sur Yvette, France.
    Asensio, Maria-Carmen
    LOrme Merisiers, Synchrotron SOLEIL, St Aubin BP 48, F-91192 Gif Sur Yvette, France.
    Hammarström, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Sá, Jacinto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Canton, Sophie E.
    ELI HU Nonprofit Ltd, ELI ALPS, Dugonicster 13, H-6720 Szeged, Hungary;Deutsch Elektronen Synchrotron DESY, Attosci Grp, Notkestr 85, D-22607 Hamburg, Germany.
    Zheng, Kaibo
    Tech Univ Denmark, Dept Chem, DK-2800 Kongens Lyngby, Denmark;Lund Univ, Dept Chem Phys & NanoLund, Box 124, S-22100 Lund, Sweden.
    Pullerits, Tonu
    Lund Univ, Dept Chem Phys & NanoLund, Box 124, S-22100 Lund, Sweden.
    Chi, Qijin
    Tech Univ Denmark, Dept Chem, DK-2800 Kongens Lyngby, Denmark.
    Inorganic Ions Assisted the Anisotropic Growth of CsPbCl3 Nanowires with Surface Passivation Effect2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 35, s. 29574-29582Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    All-inorganic halide perovskite nanowires (NWs) exhibit improved thermal and hydrolysis stability and could thus play a vital role in nanoscale optoelectronics. Among them, blue-light-based devices are extremely limited because of the lack of a facile method to obtain high-purity CsPbCl3 NWs. Herein, we report a direct and facile method for the synthesis of CsPbCl3 NWs assisted by inorganic ions that served both as a morphology controlling agent for the anisotropic growth of nanomaterials and a surface passivation species modulating the surface of nanomaterials. This new approach allows us to obtain high-purity and size-uniform NWs as long as 500 nm in length and 20 nm in diameter with high reproducibility. X-ray photoelectron spectroscopy and ultrafast spectroscopic measurements confirmed that a reduced band gap caused by the surface species of NWs relative to nanocubes (NCs) was achieved at the photon energy of 160 eV because of the hybrid surface passivation contributed by adsorbed inorganic ions. The resulting NWs demonstrate significantly enhanced photoelectrochemical performances, 3.5-fold increase in the photocurrent generation, and notably improved stability compared to their NC counterparts. Our results suggest that the newly designed NWs could be a promising material for the development of nanoscale optoelectronic devices.

  • 104. Taylor, Sarah F. R.
    et al.
    Sa, Jacinto
    Hardacre, Christopher
    Friedel-Crafts Alkylation of Aromatics with Benzyl Alcohol over Gold-Modified Silica2011Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 3, nr 1, s. 119-121Artikkel i tidsskrift (Fagfellevurdert)
  • 105. Touitou, Jamal
    et al.
    Aiouache, Farid
    Burch, Robbie
    Douglas, Roy
    Hardacre, Christopher
    Morgan, Kevin
    Sa, Jacinto
    Stewart, Caomhan
    Stewart, Jonathan
    Goguet, Alexandre
    Evaluation of an in situ spatial resolution instrument for fixed beds through the assessment of the invasiveness of probes and a comparison with a micro-kinetic model2014Inngår i: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 319, s. 239-246Artikkel i tidsskrift (Fagfellevurdert)
  • 106. Touitou, Jamal
    et al.
    Burch, Robbie
    Hardacre, Christopher
    McManus, Colin
    Morgan, Kevin
    Sá, Jacinto
    Goguet, Alexandre
    An in situ spatially resolved analytical technique to simultaneously probe gas phase reactions and temperature within the packed bed of a plug flow reactor.2013Inngår i: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 138, nr 10, s. 2858-62Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper reports the detailed description and validation of a fully automated, computer controlled analytical method to spatially probe the gas composition and thermal characteristics in packed bed systems. As an exemplar, we have examined a heterogeneously catalysed gas phase reaction within the bed of a powdered oxide supported metal catalyst. The design of the gas sampling and the temperature recording systems are disclosed. A stationary capillary with holes drilled in its wall and a moveable reactor coupled with a mass spectrometer are used to enable sampling and analysis. This method has been designed to limit the invasiveness of the probe on the reactor by using the smallest combination of thermocouple and capillary which can be employed practically. An 80 μm (O.D.) thermocouple has been inserted in a 250 μm (O.D.) capillary. The thermocouple is aligned with the sampling holes to enable both the gas composition and temperature profiles to be simultaneously measured at equivalent spatially resolved positions. This analysis technique has been validated by studying CO oxidation over a 1% Pt/Al2O3 catalyst and the spatial resolution profiles of chemical species concentrations and temperature as a function of the axial position within the catalyst bed are reported.

  • 107. tSaoir, Meabh Nic An
    et al.
    Abreu Fernandes, Daniel Luis
    Sa, Jacinto
    McMaster, Michael
    Kitagawa, Kuniyuki
    Hardacre, Christopher
    Aiouache, Farid
    Visualization of water vapour flow in a packed bed adsorber by near-infrared diffused transmittance tomography2011Inngår i: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 66, nr 24, s. 6407-6423Artikkel i tidsskrift (Fagfellevurdert)
  • 108. Tsaoir, Meabh Nic An
    et al.
    Fernandes, Daniel Luis Abreu
    Sa, Jacinto
    Kitagawa, Kuniyuki
    Hardacre, Christopher
    Aiouache, Farid
    Three-Dimensional Water Vapor Visualization in Porous Packing by Near-Infrared Diffuse Transmittance Tomography2012Inngår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 51, nr 26, s. 8875-8882Artikkel i tidsskrift (Fagfellevurdert)
  • 109.
    Tyrala, Krzysztof
    et al.
    Institute of Physics, Jan Kochanowski University.
    Wojtaszek, Klaudia
    Institute of Physics, Jan Kochanowski University.
    Pajek, Marek
    Institute of Physics, Jan Kochanowski University.
    Kayser, Yves
    Physikalisch-Technische Bundesanstalt (PTB).
    Milne, Christopher
    Paul Scherrer Institute.
    Sá, Jacinto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Institute of Physical Chemistry, Polish Academy of Sciences.
    Szlachetko, Jakub
    Institute of Physics, Jan Kochanowski University; Institute of Physical Chemistry, Polish Academy of Sciences.
    State-Population Narrowing Effect in Two-Photon Absorption for Intense Hard X-ray Pulses2017Inngår i: Applied Sciences: APPS, ISSN 1454-5101, E-ISSN 1454-5101, Vol. 7, nr 7, artikkel-id 653Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on studies of state-populations during the two-photon absorption process using intense X-ray pulses. The calculations were performed in a time-dependent manner using a simple three-level model expressed by coupled rate equations. We show that the proposed approach describes well the measured rates of X-rays excited in the one-photon and two-photon absorption processes, and allows detailed investigation of the state population dynamics during the course of the incident X-ray pulse. Finally, we demonstrate that the nonlinear interaction of X-ray pulses with atoms leads to a time-narrowing of state populations. This narrowing-effect is attributed to a quadratic incidence X-ray intensity dependence characteristic for nonlinear interactions of photons with matter.

  • 110.
    Wojtaszek, Klaudia
    et al.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.
    Wach, Anna
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.
    Czapla-Masztafiak, Joanna
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.
    Tyrala, Krzysztof
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.
    Sá, Jacinto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Polish Acad Sci, Inst Phys Chem, Warsaw, Poland.
    Özer, Luetfiye Yildiz
    Khalifa Univ Sci & Technol, Dept Chem Engn, POB 54224, Abu Dhabi, U Arab Emirates.
    Garlisi, Corrado
    Khalifa Univ Sci & Technol, Dept Chem Engn, POB 54224, Abu Dhabi, U Arab Emirates.
    Palmisano, Giovanni
    Khalifa Univ Sci & Technol, Dept Chem Engn, POB 54224, Abu Dhabi, U Arab Emirates.
    Szlachetko, Jakub
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.
    The influence of nitrogen doping on the electronic structure of the valence and conduction band in TiO22019Inngår i: Journal of Synchrotron Radiation, ISSN 0909-0495, E-ISSN 1600-5775, Vol. 26, s. 145-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    X-ray emission spectroscopy (XES) and X-ray absorption spectroscopy (XAS) provide a unique opportunity to probe both the highest occupied and the lowest unoccupied states in matter with bulk sensitivity. In this work, a combination of valence-to-core XES and pre-edge XAS techniques are used to determine changes induced in the electronic structure of titanium dioxide doped with nitrogen atoms. Based on the experimental data it is shown that N-doping leads to incorporation of the p-states on the occupied electronic site. For the conduction band, a decrease in population of the lowest unoccupied d-localized orbitals with respect to the d-delocalized orbitals is observed. As confirmed by theoretical calculations, the N p-states in TiO2 structure are characterized by higher binding energy than the O p-states which gives a smaller value of the band-gap energy for the doped material.

  • 111. Zienkiewicz, Małgorzata
    et al.
    Szlachetko, Jakub
    Lothschütz, Christian
    Hodorowicz, Maciej
    Jabłońska-Wawrzycka, Agnieszka
    Sá, Jacinto
    Barszcz, Barbara
    A novel single-site manganese(II) complex of a pyridine derivative as a catalase mimetic for disproportionation of H2O2 in water.2013Inngår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 42, nr 21, s. 7761-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel single site Mn(II) complex was successfully synthesized and tested in the aqueous disproportionation of hydrogen peroxide. The complex was found to be stable (HR-XAS) and exhibits catalase-like activity in neutral pH. Theoretical calculations suggested a reaction mechanism involving two complexes, changes in metal oxidation state and proton shuttling.

  • 112.
    Zienkiewicz-Machnik, Malgorzata
    et al.
    Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Goszewska, Ilona
    Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Srebowata, Anna
    Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Kubas, Adam
    Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Gizinski, Damian
    Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Slowik, Grzegorz
    Marie Curie Sklodowska Univ, Dept Chem Technol, Fac Chem, PL-20031 Lublin, Poland.
    Matus, Krzysztof
    Silesian Tech Univ, Inst Engn Mat & Biomat, Konarskiego 18A, PL-44100 Gliwice, Poland.
    Lisovytskiy, Dmytro
    Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Pisarek, Marcin
    Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Sá, Jacinto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland.
    Tuning nano-nickel selectivity with tin in flow hydrogenation of 6-methyl-5-hepten-2-one by surface organometallic chemistry modification2018Inngår i: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 308, s. 38-44Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemoselective flow hydrogenation of 6-methyl-5-hepten-2-one was performed over nano-nickel catalysts. The parent catalyst composed solely of nickel nanoparticles grafted on the polymeric resin exhibited high activity and selectivity towards C=C bond saturation but its modification with small quantities of tin significantly increased its ability to perform C=O bond hydrogenation. The post-synthetic modification of the parent catalyst was achieved by surface organometallic chemistry approach and performed in the same flow micro-reactor, which was used for the catalytic studies, providing a methodology for online modification of parent catalysts.

123 101 - 112 of 112
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