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Publications (10 of 92) Show all publications
Sá, J., Garlisi, C., Palmisano, G., Czapla-Masztafiak, J., Kayser, Y. & Szlachetko, J. (2018). Differences between bulk and surface electronic structure of doped TiO2 with soft-elements (C, N and S). Materials Chemistry and Physics, 208, 281-288
Open this publication in new window or tab >>Differences between bulk and surface electronic structure of doped TiO2 with soft-elements (C, N and S)
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2018 (English)In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 208, p. 281-288Article in journal (Refereed) Published
Abstract [en]

Herein, we report a systematic study on the electronic structure of surface and bulk TiO2 doped with C, N or S. The results were attained with a semi-empirical method consisting of a combination between resonant X-ray emission spectroscopy (RXES) measurements and localized density of states (LDOS) simulations. Experimental TiO2 RXES data was used to fit FEFF code empirical parameters, and subsequently frozen for the theoretical analysis of LDOS of TiO2 doped materials. The results show significant electronic structure differences between bulk and surface doping, as well as in the nearest Ti atom electronic structure if it is located at the surface or sub-surface, with potential consequences to the photo-catalytic process. The methodology can be adapted to study other dopants, morphologies, structures and surface terminations and as well as other inorganic semiconductors.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2018
Keywords
TiO2 doping, Electronic structure analysis, Surface vs bulk
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-350279 (URN)10.1016/j.matchemphys.2018.01.041 (DOI)000426223800034 ()
Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2018-05-14Bibliographically approved
Bonarowska, M., Zielinski, M., Matus, K., Sá, J. & Srebowata, A. (2018). Influence of microwave activation on the catalytic behavior of Pd-Au/C catalysts employed in the hydrodechlorination of tetrachloromethane. Reaction Kinetics, Mechanisms and Catalysis, 124(1), 375-388
Open this publication in new window or tab >>Influence of microwave activation on the catalytic behavior of Pd-Au/C catalysts employed in the hydrodechlorination of tetrachloromethane
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2018 (English)In: Reaction Kinetics, Mechanisms and Catalysis, ISSN 1878-5190, E-ISSN 1878-5204, Vol. 124, no 1, p. 375-388Article in journal (Refereed) Published
Abstract [en]

This work investigates the influence of activation by microwave irradiation on the catalytic properties of Pd-Au/C-Sibunit catalysts in the hydrodechlorination of CCl4. Pd and Pd-Au samples were thoroughly characterized by CO chemisorption, X-ray diffraction, TPHD and STEM, and used in gas phase hydrodechlorination of tetrachloromethane. The studies showed that homogenous Pd-Au alloys are formed more efficiently if short-time microwave activation is applied instead of conventional activation by H-2 reduction at 380 A degrees C. These catalysts show higher activity, stability and higher selectivity towards the desired products (C1-C5 hydrocarbons) than the catalysts activated by conventional reduction in 10%H-2/Ar flow.

Keywords
Microwave activation, Tetrachloromethane, Hydrodechlorination, Pd-Au alloys
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-353357 (URN)10.1007/s11144-018-1364-6 (DOI)000430556600026 ()
Available from: 2018-06-12 Created: 2018-06-12 Last updated: 2018-06-12Bibliographically approved
Ozer, L. Y., Apostoleris, H., Ravaux, F., Shylin, S. I., Mamedov, F., Lindblad, A., . . . Palmisano, G. (2018). Long-Lasting Non-hydrogenated Dark Titanium Dioxide: Medium Vacuum Anneal for Enhanced Visible Activity of Modified Multiphase Photocatalysts. ChemCatChem, 10(14), 2949-2954
Open this publication in new window or tab >>Long-Lasting Non-hydrogenated Dark Titanium Dioxide: Medium Vacuum Anneal for Enhanced Visible Activity of Modified Multiphase Photocatalysts
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2018 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 10, no 14, p. 2949-2954Article in journal (Refereed) Published
Abstract [en]

Abstract Multiphase TiO2 was stably modified by vacuum treatment for a dramatic improvement in visible-light absorption and photocatalytic reactivity. The samples were made of rutile-brookite, bare or N doped, and were grown on reduced graphene oxide. The stable introduction of Ti3+ species and oxygen vacancies resulting in mitigated electron?hole recombination was identified as the main responsible factor, along with a change in surface charges.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
Keywords
doping, photocatalysis, titanium, vacuum annealing, visible-light radiation
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-359437 (URN)10.1002/cctc.201800097 (DOI)
Available from: 2018-09-03 Created: 2018-09-03 Last updated: 2018-09-03
Zienkiewicz-Machnik, M., Goszewska, I., Srebowata, A., Kubas, A., Gizinski, D., Slowik, G., . . . Sá, J. (2018). Tuning nano-nickel selectivity with tin in flow hydrogenation of 6-methyl-5-hepten-2-one by surface organometallic chemistry modification. Catalysis Today, 308, 38-44
Open this publication in new window or tab >>Tuning nano-nickel selectivity with tin in flow hydrogenation of 6-methyl-5-hepten-2-one by surface organometallic chemistry modification
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2018 (English)In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 308, p. 38-44Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Chemoselective flow hydrogenation, 6-methyl-5-hepten-2-one, Nano-Ni grafted on resin, Tin surface modification
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-352559 (URN)10.1016/j.cattod.2017.08.062 (DOI)000429527800005 ()
Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2018-08-08Bibliographically approved
Miles, J., Fernandes, D., Young, A., Bond, C. M., Crane, S. W., Ghafur, O., . . . Greenwood, J. B. (2017). A new technique for probing chirality via photoelectron circular dichroism. Analytica Chimica Acta, 984, 134-139
Open this publication in new window or tab >>A new technique for probing chirality via photoelectron circular dichroism
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2017 (English)In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 984, p. 134-139Article in journal (Refereed) Published
Abstract [en]

We present a proof-of-principle approach for discriminating chiral enantiomers based on the phenomenon of multiphoton photoelectron circular dichroism. A novel stereo detection setup was used to measure the number of photoelectrons emitted from chiral molecules in directions parallel or antiparallel to the propagation of the ionising femtosecond laser pulses. In this study, we show how these asymmetries in the ketones camphor and fenchone depend upon the ellipticity of the laser pulses and the enantiomeric excess of the sample. By using a high repetition rate femtosecond laser, enantiomer excesses with uncertainties at the few-percent level could be measured in close to real-time. As the instrument is compact, and commercial turnkey femtosecond lasers are readily available, the development of a stand-alone chiral analysis instrument for a range of applications is now possible.

Place, publisher, year, edition, pages
Amsterdam: ELSEVIER SCIENCE BV, 2017
Keywords
Chirality, Enantiomer excess, Photoelectron spectroscopy, Time-of-flight mass spectrometry, Femtosecond laser ionization
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-330538 (URN)10.1016/j.aca.2017.06.051 (DOI)000408360600011 ()
Available from: 2017-10-04 Created: 2017-10-04 Last updated: 2017-10-04
Goszewska, I., Gizinski, D., Zienkiewicz-Machnik, M., Lisovytskiy, D., Nikiforov, K., Masternak, J., . . . Sá, J. (2017). A novel nano-palladium catalyst for continuous-flow chemoselective hydrogenation reactions. Catalysis communications, 94, 65-68
Open this publication in new window or tab >>A novel nano-palladium catalyst for continuous-flow chemoselective hydrogenation reactions
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2017 (English)In: Catalysis communications, ISSN 1566-7367, E-ISSN 1873-3905, Vol. 94, p. 65-68Article in journal (Refereed) Published
Abstract [en]

Herein, we report a catalyst composed of palladium nanoparticles immobilized on polymeric resin for chemoselective hydrogenation reactions under flow conditions. The catalyst exhibits high activity and selectivity towards hydrogenation of C=C double bond, as confirmed in the hydrogenation of 2-heptene and 6-methyl-5-hepten-2-one.

Keywords
Flow chemoselective hydrogenation, Nano-Pd grafted on resin, 6-Methyl-5-hepten-2-one, 2-Heptene
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-322521 (URN)10.1016/j.catcom.2017.02.014 (DOI)000399852600015 ()
Available from: 2017-05-29 Created: 2017-05-29 Last updated: 2017-05-29Bibliographically approved
Gizinski, D., Goszewska, I., Zielinski, M., Lisovytskiy, D., Nikiforov, K., Masternak, J., . . . Sá, J. (2017). Chemoselective flow hydrogenation of alpha,beta - Unsaturated aldehyde with nano-nickel. Catalysis communications, 98, 17-21
Open this publication in new window or tab >>Chemoselective flow hydrogenation of alpha,beta - Unsaturated aldehyde with nano-nickel
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2017 (English)In: Catalysis communications, ISSN 1566-7367, E-ISSN 1873-3905, Vol. 98, p. 17-21Article in journal (Refereed) Published
Abstract [en]

Herein, it is presented a novel catalytic system for the continuous flow chemoselective hydrogenation of a,alpha,beta- unsaturated aldehydes used in the production of high value cosmetics and pharmaceuticals precursors. The reaction was catalyzed by nano nickel particles grafted on polymeric support, synthesized via a simple, adaptable and green methodology. The system was highly active and very selective to C=C bond saturation.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2017
Keywords
Hydrogenation in flow, Nano-nickel catalyst, Resin supported catalyst, Selective hydrogenation of alpha, beta-unsaturated, aldehydes
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-328966 (URN)10.1016/j.catcom.2017.04.048 (DOI)000403519700005 ()
Available from: 2017-09-13 Created: 2017-09-13 Last updated: 2017-09-13Bibliographically approved
Sá, J., Fernandes, D. L. A., Pavliuk, M. V. & Szlachetko, J. (2017). Controlling dark catalysis with quasi half-cycle terahertz pulses. Catalysis Science & Technology, 7(5), 1050-1054
Open this publication in new window or tab >>Controlling dark catalysis with quasi half-cycle terahertz pulses
2017 (English)In: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 7, no 5, p. 1050-1054Article in journal (Refereed) Published
Abstract [en]

This study reports the changes in the platinum electronic structure induced by a strong electric field originated from quasi half-cycle THz pulses, which forces the C-O molecule to dissociate. The changes could be rationalized via a simple analysis of the local density-of-states and easily characterised via high resolution X-ray absorption spectroscopy (HR-XAS). Thus, conferring half-cycle THz pulses the capability of triggering dark catalytic processes required to follow real time catalytic bond rupture or formation, i.e., time-resolved measurements using THz as the pump and HR-XAS as the probe.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2017
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-320254 (URN)10.1039/c6cy02651f (DOI)000396137800004 ()
Available from: 2017-04-19 Created: 2017-04-19 Last updated: 2017-04-19Bibliographically approved
Czapla-Masztafiak, J., Nogueira, J. J., Lipiec, E., Kwiatek, W. M., Wood, B. R., Deacon, G. B., . . . Sá, J. (2017). Direct Determination of Metal Complexes' Interaction with DNA by Atomic Telemetry and Multiscale Molecular Dynamics. Journal of Physical Chemistry Letters, 8(4), 805-811
Open this publication in new window or tab >>Direct Determination of Metal Complexes' Interaction with DNA by Atomic Telemetry and Multiscale Molecular Dynamics
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2017 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 8, no 4, p. 805-811Article in journal (Refereed) Published
Abstract [en]

The lack of molecular mechanistic understanding of the interaction between metal complexes and biomolecules hampers their potential medical use. Herein we present a robust procedure combining resonant X-ray emission spectroscopy and multiscale molecular dynamics simulations, which allows for straightforward elucidation of the precise interaction mechanism at the atomic level. The report unveils an unforeseen hydrolysis process and DNA binding of [Pt{N(p-HC6F4)CH2}(2)py(2)] (Pt103), which showed potential cytotoxic activity in the past. Pt103 preferentially coordinates to adjacent adenine sites, instead of guanine sites as in cisplatin, because of its hydrogen bond ability. Comparison with previous research on cisplatin suggests that selective binding to guanine or adenine may be achieved by controlling the acidity of the compound.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
National Category
Physical Chemistry Medicinal Chemistry
Identifiers
urn:nbn:se:uu:diva-319563 (URN)10.1021/acs.jpclett.7b00070 (DOI)000394484100016 ()28151686 (PubMedID)
Funder
Australian Research Council, FT120100926
Available from: 2017-04-06 Created: 2017-04-06 Last updated: 2018-01-13Bibliographically approved
Błachucki, W., Hoszowska, J., Dousse, J.-C., Kayser, Y., Stachura, R., Tyrała, K., . . . Szlachetko, J. (2017). High energy resolution off-resonant spectroscopy: A review. Spectrochimica Acta Part B - Atomic Spectroscopy, 136(Supplement C), 23-33
Open this publication in new window or tab >>High energy resolution off-resonant spectroscopy: A review
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2017 (English)In: Spectrochimica Acta Part B - Atomic Spectroscopy, ISSN 0584-8547, E-ISSN 1873-3565, Vol. 136, no Supplement C, p. 23-33Article, review/survey (Refereed) Published
Abstract [en]

We review the high energy resolution off-resonant spectroscopy (HEROS) technique. HEROS probes the unoccupied electronic states of matter in a single-shot manner thanks to the combination of off-resonant excitation around atomic core states using wavelength dispersive X-ray detection setups. In this review we provide a general introduction to the field of X-ray spectroscopy together with the specification of the available X-ray techniques and X-ray methodologies. Next, the theoretical description of the HEROS approach is introduced with a special focus on the derivation of the X-ray emission and X-ray absorption correspondence relation at off-resonant excitation conditions. Finally, a number of experimental HEROS reports are reviewed in the field of chemistry and material science. We emphasize the applicability of HEROS to pulsed X-ray sources, like X-ray free electron lasers, and support the review with experimental examples. The review is complemented with perspectives on and possible further applications of the HEROS technique to the field of X-ray science.

Keywords
High energy resolution off-resonant X-ray spectroscopy, Time-resolved chemical speciation, Synchrotron and X-ray free electron laser radiation
National Category
Physical Chemistry
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-337010 (URN)10.1016/j.sab.2017.08.002 (DOI)000413608500004 ()
Available from: 2017-12-19 Created: 2017-12-19 Last updated: 2018-03-23Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2124-9510

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