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19 results on '"Luis Cardenas"'

1. Room-temperature conversion of Cu2−xSe to CuAgSe nanoparticles to enhance the photocatalytic performance of their composites with TiO2

Author

Frederic Dappozze, Deobrat Singh, Shashank Mishra, Chantal Guillard, Sweta Gahlot, Luis Cardenas, Laurence Burel, Rajeev Ahuja, David Amans, IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Catalytic and Atmospheric Reactivity for the Environment (CARE), Uppsala University, IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), IRCELYON-Microscopie (MICROSCOPIE), Luminescence (LUMINESCENCE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Materials science, education, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Inorganic Chemistry, Metal, chemistry.chemical_compound, Selenide, Photodegradation, reproductive and urinary physiology, health care economics and organizations, Nanocomposite, integumentary system, Heterojunction, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, [SDE.ES]Environmental Sciences/Environmental and Society, female genital diseases and pregnancy complications, 0104 chemical sciences, Chemical engineering, chemistry, visual_art, visual_art.visual_art_medium, Photocatalysis, 0210 nano-technology, Ternary operation
Abstract

Rational design and precise engineering are needed to optimize the structural and chemical parameters of functional materials. In this work, we demonstrate how pre-formed binary metal selenides can be an excellent synthetic choice for the synthesis of ternary coinage metal selenide nanoparticles (NPs) with controlled composition. The mild conditions required to obtain these ternary coinage metal selenide NPs offered an easy synthesis of n% CuAgSe–TiO2 (n = 0.01, 0.1, 0.3 and 1.0 mol%) nanocomposites for photocatalytic applications without compromising the structural and morphological characteristics of TiO2 and without having any organic ligands around the NPs. The use of ternary metal selenide nanocomposites CuAgSe–TiO2 results in a clear improvement in their photocatalytic activity for the photodegradation of formic acid as compared to the well-known benchmark for photocatalysis, TiO2 (P25), and its binary metal selenide nanocomposites Cu2−xSe–TiO2. DFT calculations establish semi-metallic behavior of CuAgSe NPs and show that CuAgSe–TiO2 forms a semimetallic-semiconductor heterojunction allowing a better charge separation to enhance its photocatalytic activity.

Published
2020

2. UPS and UV spectroscopies combined to position energy levels of TiO2 anatase and rutile nanopowders

Author

Pavel Afanasiev, Luis Cardenas, Christophe Geantet, Clément Maheu, Eric Puzenat, IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS)

Subjects
Chemical Physics (physics.chem-ph), Anatase, Condensed Matter - Materials Science, Materials science, Analytical chemistry, General Physics and Astronomy, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, Substrate (electronics), [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, [SDE.ES]Environmental Sciences/Environmental and Society, Spectral line, 0104 chemical sciences, Electrophoretic deposition, Rutile, Physics - Chemical Physics, Photocatalysis, Physical and Theoretical Chemistry, 0210 nano-technology, Spectroscopy, Single crystal
Abstract

An accurate experimental determination of electronic structures in semi-conductor nanopowders is a challenging task. We propose here to combine UPS and UV-Vis spectroscopies in order to get the full description of the electronic band alignment of powder samples, TiO2 rutile and anatase. For UPS measurements, two preparation methods, namely the dropping method and electrophoretic deposition, were used to prepare layers of titania powders on a conducting substrate, ITO or Ag. Both methods lead to comparable results, with a quantitative description of the energy levels from the valence band. Combining these results with the UV-Vis spectra of the same powders enables the determination of the absolute position of the valence band maximum and the conduction band minimum. Combined UPS-UV-Vis spectroscopy provides a better insight into the properties of a powdered material which can differ from single crystal model systems. It can also be used to predict the electronic transfer in mixed phase systems during photocatalytic processes.

Published
2022

3. Ultradispersed Mo/TiO2 catalysts for CO2 hydrogenation to methanol

Author

Virginia Pérez Dieste, Eric Puzenat, Laurent Piccolo, Franck Morfin, Pavel Afanasiev, Ruben Checa, Mounib Bahri, Ovidiu Ersen, Yaya Lefkir, Thomas Len, Luis Cardenas, Noémie Perret, Ignacio J. Villar-Garcia, Jordi Llorca, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia, IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-C'Durable (CDURABLE), and IRCELYON-Ingéniérie, du matériau au réacteur (ING)

Subjects
Materials science, chemistry.chemical_element, 02 engineering and technology, Molybdate, 010402 general chemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, Enginyeria química [Àrees temàtiques de la UPC], X-ray photoelectron spectroscopy, Scanning transmission electron microscopy, Environmental Chemistry, Spectroscopy, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, [SDE.ES]Environmental Sciences/Environmental and Society, Pollution, 0104 chemical sciences, chemistry, Chemical engineering, Green chemistry, Rutile, Molybdenum, Química verda, Methanol, 0210 nano-technology
Abstract

fff; International audience; Mo/TiO2 catalysts with atomic dispersion of molybdenum appear active and stable in the gas-phase hydrogenation of CO2. The comparison between various titania materials shows a crucial effect of the support surface structure on the methanol yield. Molybdenum supported at low coverage on rutile titania nanorods is the most active and methanol-selective system. From catalyst characterization by aberration-corrected scanning transmission electron microscopy, near-ambient pressure X-ray photoelectron spectroscopy, diffuse reflectance UV-vis spectroscopy, and temperature-programmed techniques, we suggest that the most active catalysts for methanol production involve atomically-dispersed oxomolybdate species with high reducibility and strong interaction with the rutile support.

Published
2021

4. Photocatalytic production of H2 is a multi-criteria optimization problem: case study of RuS2/TiO2

Author

Pavel Afanasiev, Clément Maheu, Christophe Geantet, Luis Cardenas, Eric Puzenat, Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)

Subjects
Materials science, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, Activation energy, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Catalysis, Electron transfer, symbols.namesake, Photocatalytic hydrogen evolution reaction, Dehydrogenation, Co- catalyst, ComputingMilieux_MISCELLANEOUS, Hydrogen production, Arrhenius equation, Ruthenium disulfide, General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Ruthenium, chemistry, Photocatalysis, symbols, Titanium dioxide, UPS analysis, 0210 nano-technology, [CHIM.OTHE]Chemical Sciences/Other
Abstract

Many parameters influence the photocatalytic production of H2. Identifying and quantifying them is necessary for correct comparison of photocatalysts and right understanding of involved mechanism. In this work, we studied the photocatalytic dehydrogenation of isopropanol with titania-supported ruthenium disulfide. We studied the influence of seven parameters on the photocatalytic activity: the temperature, the composition of the reactive mixture, the mass of the photocatalyst, the flux and the energy of the incident photons, the co-catalyst loading and the nature of the support. Their influence was studied, not only on the rate of hydrogen production (or photon yield) but also on the apparent activation energy and on the pre-exponential factor, deduced from an Arrhenius law. The photon yield as a function of the co-catalyst loading show an optimum of activity. A 6.9 % photon yield was obtained at 0.84 wt% and E p h o t o n s = 3.65 e V . The rate-determining step for the photocatalytic dehydrogenation of the isopropanol with RuS2/TiO2 is, at optimal conditions, the electron transfer from TiO2 to RuS2. The latter is not favored because of the band diagrams of RuS2 and TiO2. The electron transfer can be optimized working with incident photons having a higher energy, thanks to a hot carrier effect observed in RuS2/TiO2.

Published
2020

5. Surface and Electronic Features of Fluorinated TiO 2 and Their Influence on the Photocatalytic Degradation of 1-Methylnaphthalene

Author

Leonardo Palmisano, Frederic Dappozze, Gilles Ledoux, Chantal Guillard, Mohamed Faouzi Nsib, Yves Chevalier, Luis Cardenas, David Amans, Nidhal Fessi, Ammar Houas, Francesco Parrino, Laboratoire d'automatique, de génie des procédés et de génie pharmaceutique (LAGEPP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Catalyse et Matériaux pour l’Environnement et les Procédés URCMEP (UR11ES85), Faculté des Sciences de Gabès/Université de Gabès, Campus Universitaire Cité Erriadh, Gabès 6072, Tunisia, Université de Sousse, Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Centre for Atmospheric Research Experiments (CARE), Environment and Climate Change Canada, IRCELYON-Catalytic and Atmospheric Reactivity for the Environment (CARE), Department of Industrial Engineering, University of Trento, via Sommarive 9, 38123 Trento, Italy, Università degli studi di Palermo - University of Palermo, Luminescence (LUMINESCENCE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Anions, Materials science, Halogenation, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 1-Methylnaphthalene, chemistry.chemical_compound, Degradation, Physical and Theoretical Chemistry, Photocatalytic degradation, Oxides, Fluorine, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Energy, [CHIM.POLY]Chemical Sciences/Polymers, [SDV.SP.PG]Life Sciences [q-bio]/Pharmaceutical sciences/Galenic pharmacology, Chemical engineering, chemistry, 13. Climate action, Photocatalysis, 0210 nano-technology
Abstract

International audience; Surface fluorination improves the photocatalytic activity of TiO2, and the influences of various features of fluorinated TiO2 (TiO2–F) have often been discussed in the literature. The present paper addresses the changes induced by surface fluorination on the morphological, structural, surface, and electronic features of TiO2. In particular, X-ray diffraction, specific surface area analysis, and transmission and scanning electron microscopy give evidence that surface fluorination does not affect the structural properties and the morphology of TiO2 nanoparticles. In contrast, fluorination induces changes of surface and electronic properties. Chemical and thermogravimetric analyses show that surface fluorination can reach up to 50% of original Ti–OH surface sites. The surface charge of TiO2 turns more negative upon fluorination, as shown by a shift of the point of zero charge toward lower pH. Electronic properties are deeply characterized by combining diffuse reflectance, X-ray, and UV photoelectron spectroscopies, as well as time-resolved fluorescence spectroscopy, and photoelectrochemical measurements. Results show the presence of intra-band-gap energy states induced by the local interaction of chemisorbed fluorine atoms. Such energy levels are close to the valence band. The unique surface and electronic properties of TiO2–F make it a promising material for the photocatalytic degradation of poorly soluble emerging pollutants such as 1-methylnaphtalene. In particular, TiO2–F demonstrates faster degradation kinetics with respect to both the pristine material and TiO2 P25 used as a benchmark standard.

Published
2020

6. Microstructure and hydrothermal ageing of alumina-zirconia composites modified by laser engraving

Author

Thierry Douillard, Laurent Gremillard, Helen Reveron, K. Hans, A. Vogl, Luis Cardenas, Thomas Oberbach, Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Mathys Orthopaedie GmbH

Subjects
Materials science, 02 engineering and technology, 01 natural sciences, Hydrothermal circulation, law.invention, law, Laser engraving, 0103 physical sciences, Materials Chemistry, Cubic zirconia, Ceramic, Composite material, Microstructure, 010302 applied physics, Hydrothermal ageing, Zirconia-alumina composites, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Laser, visual_art, Ceramics and Composites, visual_art.visual_art_medium, 0210 nano-technology, Lasing threshold, Solid solution
Abstract

International audience; Laser engraving is more and more commonly used to write permanent identity features on medical devices. In particular, it is performed on ceramic heads for hip prostheses. Since these components are submitted to high mechanical loading during long periods of time (several years), it is critical to assess the influence of laser engraving on their durability. In the present article, laser marking of zirconia-toughened alumina and alumina-toughened zirconia resulted in an important colour change. It did not affect notably the resistance to hydrothermal ageing, despite important microstructural changes (in particular formation of a zirconia-alumina solid solution layer some tenths of micrometres thick). The formation of this original microstructure was explained by the fast cooling rate after lasing.

Published
2020

7. Structure Sensitivity of 2,3-Butanediol Dehydration to Butadiene over Rare Earth Orthophosphate Catalysts

Author

Thi Tuyet Nhung Nguyen, Karine Jaillardon, Maxime Huchede, Luis Cardenas, Mimoun Aouine, Jean-Marc M. Millet, IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Microscopie (MICROSCOPIE), and IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN)

Subjects
Inorganic chemistry, Rare earth, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 021001 nanoscience & nanotechnology, medicine.disease, Phosphate, 01 natural sciences, [SDE.ES]Environmental Sciences/Environmental and Society, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Catalysis, chemistry.chemical_compound, General Energy, chemistry, 2,3-Butanediol, medicine, Dehydration, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract

NdPO4 has been studied as a model rare earth phosphate catalyst for the dehydration of 2,3-butanediol (2,3-BDO) to butadiene (BD), in order to understand the influence of structure and morphology o...

Published
2020

8. CO dissociation on Pt-Sn nanoparticles triggers Sn oxidation and alloy segregation

Author

Chloé Thieuleux, Luis Cardenas, Debora Motta-Meira, Christina Theodoridi, A. Moscu, Yves Schuurman, Giovanni Agostini, Frederic Meunier, IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and IRCELYON-Ingéniérie, du matériau au réacteur (ING)

Subjects
Alloy, Inorganic chemistry, chemistry.chemical_element, [CHIM.CATA]Chemical Sciences/Catalysis, 02 engineering and technology, engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, [SDE.ES]Environmental Sciences/Environmental and Society, 01 natural sciences, Catalysis, XANES, Dissociation (chemistry), 0104 chemical sciences, Metal, Boudouard reaction, chemistry, X-ray photoelectron spectroscopy, visual_art, engineering, visual_art.visual_art_medium, Physical and Theoretical Chemistry, 0210 nano-technology, Tin
Abstract

XPS+ING+LCS:YSC:FRM; International audience; Identifying the causes of the segregation of Pt-based alloy nanoparticles is crucial for the design and operation of the corresponding catalysts and electrodes. This article describes a yet unreported mode of alloy segregation upon exposure to CO. In situ IR studies indicated that Pt-Sn alloy nanoparticles were not stable under (i) H2-free CO at any temperature or (ii) CO/H2 mixtures at temperatures below ca. 450 K. This was rationalized by the ability of Pt to dissociate CO. The oxygen adatoms readily reacted with metallic Sn to form a SnOx species, leading to Pt-Sn segregation, alongside carbon deposition. XPS and XANES analyses confirmed Sn reoxidation. While a contamination by traces of O2 at the sub-ppm level cannot be excluded, the data reported indicate that the structural modifications undergone by the Pt-Sn nanoparticles are more consistent with a reaction involving CO rather than one involving O2. In particular, the XPS analysis after CO exposure revealed an increased fraction of graphitic carbon, while that of oxidized carbon decreased. Thermodynamic calculations indicate that the oxidation of tin by CO, with concomitant carbon formation (Sn + CO → SnO + C) is as favourable as Boudouard reaction (2 CO → CO2 + C) at low temperatures. Alloy stability in the presence of CO must therefore be a concern when CO dissociation is possible and one of the alloyed metal is oxophilic.

Published
2018

9. Titania - Supported transition metals sulfides as photocatalysts for hydrogen production from propan-2-ol and methanol

Author

Eric Puzenat, Clément Maheu, Pavel Afanasiev, Luis Cardenas, Christophe Geantet, IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Sulfide, Inorganic chemistry, Energy Engineering and Power Technology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, Transition metal, Thiophene, Temperature-programmed reduction, Hydrogen production, chemistry.chemical_classification, Titanium oxide, Renewable Energy, Sustainability and the Environment, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, [SDE.ES]Environmental Sciences/Environmental and Society, Hydrogen evolution reaction, 0104 chemical sciences, Fuel Technology, chemistry, Photocatalysts, Methanol, 0210 nano-technology, Transition metal sulfides, Hydrodesulfurization
Abstract

International audience; A series of transition metals sulfides deposited on anatase titania (MSx/TiO2) were prepared by precipitation of transition metals salts with thioacetamide in aqueous medium under reflux. The solids were characterized by XRD, XPS, temperature programmed reduction and transmission electron microscopy. The properties of as obtained catalysts were compared for the photocatalytic hydrogen evolution reaction (PHER) in pure methanol and water-isopropanol mixture. The sequences of PHER activity were compared with electrochemical HER and thiophene hydrodesulfurization (HDS) activity of the corresponding sulfides prepared by the same technique. For PHER, in both alcohols the most active photocatalysts contain hydrogenating sulfides of Co and Ru. However the PHER activity does not follow the same trend as electrocatalytic HER and thiophene HDS. Some sulfides, such as HgS or CuS, show poor activity in HDS and electrocatalytic HER, but have the PHER activity comparable with that of the best samples. This difference suggests that the PHER rate is not merely related to the hydrogen activating properties of the co-catalyst, but is enhanced by the transfer of photogenerated electrons from TiO2 towards the sulfide. The ranking of the co-catalysts and the PHER activity depend also on the nature of the alcohol molecule, the overall PHER rates in water-isopropanol mixture being lower than in methanol.

Published
2019

10. Bandgap Engineering from Cation Balance: the Case of Lanthanide Oxysulfide Nanoparticles

Author

Mohamed Selmane, Clément Sanchez, Christophe Geantet, Clément Maheu, Capucine Sassoye, Pierre Lecante, Clément Larquet, Corinne Chanéac, Sophie Carenco, Estelle Glais, Andrea Gauzzi, Luis Cardenas, Anh-Minh Nguyen, Lorenzo Paulatto, Chaire Chimie des matériaux hybrides, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche de Chimie Paris (IRCP), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Institut des matériaux de Paris-Centre (IMPC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), ANR-16-CE09-0005,OxySUN,Nanomatériaux d'oxysulfures et oxynitrures pour l'électrocatalyse(2016), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ministère de la Culture (MC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)

Subjects
Lanthanide, Materials science, Band gap, General Chemical Engineering, Nanoparticle, 02 engineering and technology, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Chemical physics, Materials Chemistry, Photocatalysis, Lamellar structure, Density functional theory, 0210 nano-technology, Bimetallic strip, Visible spectrum
Abstract

International audience; Among the inorganic compounds, many oxides and sulfides are known to be semiconductors. At the crossroads of these two families, oxysulfide MxOySz compounds were much less investigated because they are scarce in nature and complex to synthesize. Amongst them, lanthanide oxysulfide Ln2O2S (Ln = lanthanide) are indirect bandgap semiconductors, with wide gaps, except Ce2O2S. (Gd,Ce)2O2S anisotropic nanoparticles with hexagonal structure were obtained over the whole composition range and exhibit colors varying from white to brown with increasing Ce concentration. Bandgap engineering is thus possible, from 4.7 eV for Gd2O2S, to 2.1 eV for Gd0.6Ce1.4O2S, while the structure is preserved with a slight lattice expansion. Surprisingly, due to the limited thickness of the lamellar nanoparticles, the bandgap of the nanoparticles is direct as validated by density functional theory on slabs. The fine control of the bandgap over a wide range, solely triggered by the cation ratio, is rarely described in the literature and highly promising for further development of this class of compounds. We propose a multi-regime mechanism to rationalize the bandgap engineering over the whole composition range. This should inspire the design of other bimetallic nanoscaled compounds, in particular in the field of visible light photocatalysis.

Published
2019

11. Hammett Parameter in Microporous Solids as Macroligands for Heterogenized Photocatalysts

Author

Anne Lesage, Luis Cardenas, Elsje Alessandra Quadrelli, Florian M. Wisser, Pierrick Berruyer, David Farrusseng, Jérôme Canivet, Yorck Mohr, IRCELYON-Ingéniérie, du matériau au réacteur (ING), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), The authors are very grateful to N. Cristin and P. Mascunan for ICP-OES analysis, to L. Burel for electron microscopy, to Prof. Dr. G. Kickelbick (Saarland University) for providing access to CHN-analysis and to Dr. O. Ouari and Prof. Dr. P. Tordo (both from Aix -Marseille University) for providing polarizing agent TEKPOL. F.M.W. gratefully acknowledges financial support from the Deutsche Forschungsgemeinschaft (DFG, Postdoctoral Research Fellowship, grant number WI 4721/1-1). The authors acknowledge financial support from ERC Advanced Grant No. 320860., European Project: 320860,EC:FP7:ERC,ERC-2012-ADG_20120216,HI-SENS(2013), and Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
conjugated microporous polymers, 02 engineering and technology, 010402 general chemistry, Heterogeneous catalysis, 01 natural sciences, Catalysis, Conjugated microporous polymer, Electronic effect, Electrochemical reduction of carbon dioxide, chemistry.chemical_classification, carbon dioxide reduction, microporous materials, General Chemistry, Polymer, Microporous material, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, Hammett constant, 0104 chemical sciences, chemistry, Chemical engineering, Photocatalysis, 0210 nano-technology, photocatalysis, rhodium complex
Abstract

XPS+ING+FWI:LCS:YMO:DFA:JEC; International audience; Here we present a series of heterogeneous catalysts based on metal–organic frameworks and microporous polymers used as macroligands for heterogenized organometallic complexes. We show that both homogeneous and heterogenized catalysts follow the same linear correlation between the electronic effect of the ligand, described by the Hammett parameter, and the catalytic activity. This correlation highlights the crucial impact of the local electronic environment surrounding the active catalytic center over the long-range framework structure of the porous support. The rational design of heterogenized catalysts can thus be guided by molecular chemistry rules. The conception of highly efficient heterogeneous catalyst based on porous polymer support and driven by the Hammett parameter of bipyridine-chelating macroligand is demonstrated here for the Rh-catalyzed photoreduction of carbon dioxide with turnover frequencies up to 28 h–1, among the highest reported for heterogeneous photocatalytic formate production.

Published
2018

12. Pd Nanoparticles Dispersed on Zr-IV Organophosphonate: A Robust and Reusable Catalyst for Suzuki-Miyaura Cross-Coupling Reactions

Author

Nayanmoni Gogoi, Luis Cardenas, Suchibrata Borah, Shashank Mishra, IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS)

Subjects
Zirconium, chemistry.chemical_element, Nanoparticle, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, [SDE.ES]Environmental Sciences/Environmental and Society, Coupling reaction, 3. Good health, 0104 chemical sciences, Catalysis, Inorganic Chemistry, chemistry, Pd nanoparticles, Polymer chemistry, 0210 nano-technology, Palladium
Abstract

XPS+CDFA+SMR:LCS; International audience; Pd catalyst

Published
2018

13. Insights into the mechanism of electrocatalysis of the oxygen reduction reaction by a porphyrinic metal organic framework

Author

Alexandra Fateeva, Aude Demessence, Thomas Devic, M. Lions, Nathalie Guillou, Frédéric Maillard, Brian Abeykoon, Raphaël Chattot, Luis Cardenas, Jean-Bernard Tommasino, Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)

Subjects
02 engineering and technology, 010402 general chemistry, Electrocatalyst, Electrochemistry, Photochemistry, 01 natural sciences, Redox, Catalysis, Electron transfer, Materials Chemistry, Oxygen reduction reaction, Chemistry, fungi, Metals and Alloys, General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, [SDE.ES]Environmental Sciences/Environmental and Society, 3. Good health, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Mechanism (philosophy), Ceramics and Composites, Metal-organic framework, 0210 nano-technology
Abstract

XPS+CDFA+ADM:LCS; International audience; Metal Organic Frameworks (MOFs) have been recently proposed as promising electrocatalysts, yet the exact nature of the mechanisms in play has not been addressed in depth. By comparing the electrocatalytic activity of a MOF for the oxygen reduction reaction (ORR) and the corresponding molecular building units through electrochemical techniques, here, we investigate the nature of the catalytic sites, their redox states and the electron transfer pathways.

Published
2017

14. A new strategy to activate liquid crystal polymer samples for electroless copper deposition

Author

E. Ehret, Luis Cardenas, A. Atli, Sandra Simon, F.J. Cadete Santos Aires, P. Lourdin, IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and IRCELYON-Approches thermodynamiques, analytiques et réactionnelles intégrées (ATARI)

Subjects
Materials science, Polymers and Plastics, Inorganic chemistry, Kinetics, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Metal, Materials Chemistry, Sample preparation, chemistry.chemical_classification, Thermal decomposition, General Chemistry, Polymer, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, Copper, [SDE.ES]Environmental Sciences/Environmental and Society, 0104 chemical sciences, Surfaces, Coatings and Films, Nickel, Chemical engineering, chemistry, visual_art, visual_art.visual_art_medium, 0210 nano-technology, Palladium
Abstract

XPS+ATARI+LCS:EEH; International audience; In order to activate the polymers for electroless copper deposition, an alternative way of sample preparation is demonstrated. The samples are prepared by incorporation of a small amount (

Published
2017

15. Experimental and DFT high pressure study of fluorinated graphite (C2F)(n)

Author

C. Cavallari, Marc Dubois, Félix Balima, S. Radescu, Luis Cardenas, Nicolas Batisse, Vittoria Pischedda, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Departamento de Física Fundamental II, MALTA Consolider Team, and Instituto de Materiales y Nanotecnología, Universidad de La Laguna, Departamento de Física Fundamental II, Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)

Subjects
Valence (chemistry), Materials science, Graphene, Nanotechnology, 02 engineering and technology, General Chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Semimetal, law.invention, symbols.namesake, X-ray photoelectron spectroscopy, law, Chemical physics, 0103 physical sciences, symbols, [CHIM]Chemical Sciences, General Materials Science, Density functional theory, Graphite, van der Waals force, 010306 general physics, 0210 nano-technology, Electronic band structure
Abstract

XPS+EQUIPE-VIDE+LCS; International audience; We studied the high pressure behavior of poly(dicarbon monofluoride) (C2F)n up to 37 GPa both theoretically, within the first-principle framework of the density functional theory, taking into account van der Waals corrections to the total energy, and experimentally, combining in situ Raman spectroscopy, XRD and X-ray photoelectron spectroscopy (XPS) measurements. The (C2F)n structure has a complex mixed sp2 sp3 character where graphene layers are intercalated among sp3 carbon hybridized structural domains. We observed three phase transitions in the high pressure range explored. The first transition is observed around 12 GPa and is dominated by strain effects. Above 16 GPa the intercalated graphene layers corrugate and change from the sp2 to sp3 hybridization state. Above 25–27 GPa the new pressure-induced phase becomes unstable. We find that, by varying applied pressure or by changing the hybridization due to the fluorination of graphite, the band structure of (C2F)n can be modified, resulting in valence and conduction bands touching at the K point, as in graphene, thus turning (C2F)n into a semimetal. This could provide a new pathway to reversibly engineer the band structure and conductivity for applications in high energy density batteries.

Published
2017

16. Quasi one-dimensional band dispersion and surface metallization in long-range ordered polymeric wires

Author

Gianluca Galeotti, Muriel Sicot, Daniel Malterre, Marco Di Giovannantonio, Luis Cardenas, Giorgio Contini, François Bertran, Dmitrii F. Perepichka, Guillaume Vasseur, Yannick Fagot-Revurat, Josh Lipton-Duffin, Federico Rosei, Luc Moreau, Liangbo Liang, Vincent Meunier, Bertrand Kierren, Patrick Le Fèvre, Institut Jean Lamour ( IJL ), Université de Lorraine ( UL ) -Centre National de la Recherche Scientifique ( CNRS ), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS ( XPS ), Institut de recherches sur la catalyse et l'environnement de Lyon ( IRCELYON ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ), Énergie Matériaux Télécommunications - INRS ( EMT-INRS ), Institut National de la Recherche Scientifique [Québec] ( INRS ) -Université du Québec à Montréal ( UQAM ), Queensland University of Technology [Brisbane] ( QUT ), University of Electronic Science and Technology of China ( UESTC ), Istituto di Struttura della Materia ( ISM ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Department of Physics, University Roma II, UNiversita di Roma II, Synchrotron SOLEIL ( SSOLEIL ), Centre National de la Recherche Scientifique ( CNRS ), Department of Physics, Applied Physics, and Astronomy [Troy], Rensselaer Polytechnic Institute ( RPI ), Center for Nanophase Materials Sciences, Oak Ridge National Laboratory - Tennessee, McGill University, Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Énergie Matériaux Télécommunications - INRS (EMT-INRS), Institut National de la Recherche Scientifique [Québec] (INRS)-Université du Québec à Montréal = University of Québec in Montréal (UQAM), Queensland University of Technology [Brisbane] (QUT), University of Electronic Science and Technology of China (UESTC), Consiglio Nazionale delle Ricerche [Roma] (CNR), Università degli Studi di Roma Tor Vergata [Roma], Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Rensselaer Polytechnic Institute (RPI), Center for Nanophase Materials Sciences [Oak Ridge] (CNMS), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, McGill University = Université McGill [Montréal, Canada], and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Band gap, Science, polymer, Nanowire, Condensed matter, [ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], STM, General Physics and Astronomy, FOS: Physical sciences, Nanotechnology, 02 engineering and technology, Electronic structure, 010402 general chemistry, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Article, symbols.namesake, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Physics::Atomic and Molecular Clusters, molecules, Electronic band structure, band dispersion, one-dimensional, Multidisciplinary, Condensed Matter - Mesoscale and Nanoscale Physics, Fermi level, General Chemistry, self-assembly, 021001 nanoscience & nanotechnology, Semimetal, 0104 chemical sciences, Physical sciences, Chemical physics, ARUPS, symbols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Density functional theory, Direct and indirect band gaps, 0210 nano-technology
Abstract

On-surface covalent self-assembly of organic molecules is a very promising bottom–up approach for producing atomically controlled nanostructures. Due to their highly tuneable properties, these structures may be used as building blocks in electronic carbon-based molecular devices. Following this idea, here we report on the electronic structure of an ordered array of poly(para-phenylene) nanowires produced by surface-catalysed dehalogenative reaction. By scanning tunnelling spectroscopy we follow the quantization of unoccupied molecular states as a function of oligomer length, with Fermi level crossing observed for long chains. Angle-resolved photoelectron spectroscopy reveals a quasi-1D valence band as well as a direct gap of 1.15 eV, as the conduction band is partially filled through adsorption on the surface. Tight-binding modelling and ab initio density functional theory calculations lead to a full description of the band structure, including the gap size and charge transfer mechanisms, highlighting a strong substrate–molecule interaction that drives the system into a metallic behaviour., Polymerization on surfaces is an emerging approach for producing graphene nanoribbons with a tunable bandgap, a promising material for carbon-based electronics. Here, Vasseur et al. show quasi-one-dimensional band structure of a model semiconducting polymer synthesized directly on a supporting surface.

Published
2016
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17. Efficient hydrogen production from methane over iridium-doped ceria catalysts synthesized by solution combustion

Author

Luis Cardenas, Patrick Gélin, Mimoun Aouine, Laurent Piccolo, Thanh-Son Nguyen, Georgeta Postole, IRCELYON-Approches thermodynamiques, analytiques et réactionnelles intégrées (ATARI), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), IRCELYON-Microscopie (MICROSCOPIE), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), IRCELYON-Catalyse Hétérogène pour la Transition Energétique (CATREN), and ANR-11-BS10-0009,DINAMIC,Conception et imagerie de nanoalliages par microscopie électronique avancée pour la catalyse(2011)

Subjects
Site Requirements, Catalyst support, Inorganic chemistry, chemistry.chemical_element, Activation, 02 engineering and technology, 010402 general chemistry, Heterogeneous catalysis, Iridium, 7. Clean energy, 01 natural sciences, Catalysis, Methane, Steam reforming, chemistry.chemical_compound, Ceria, Oxide Fuel-Cell, Oxidation, Chemical Conversion, Incipient wetness impregnation, Metal Catalysts, General Environmental Science, Hydrogen production, Steam reforming of methane, Chemistry, Process Chemistry and Technology, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, Solid-Solution, [SDE.ES]Environmental Sciences/Environmental and Society, 0104 chemical sciences, Steam, Solution combustion synthesis, Mechanism, Reaction Pathways, 0210 nano-technology
Abstract

MICROSCOPIE:XPS+ATARI:ECI2D+GPO:MAO:PGE:LCS:LPI; International audience; This study reports on the investigations performed on an Ir-CeO2 (0.1 wt% Ir) catalyst, prepared for the first time by one-step solution combustion synthesis (SCS) and submitted to a number of analyses: N-2 volumetry, elemental analysis, X-ray diffraction, scanning electron microscopy, aberration-corrected high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and temperature-programmed methods. The catalyst was studied in the steam reforming of methane (SRM) at 750 degrees C, under water-deficient conditions (CH4/H2O ratio of 10) and in the presence of 220 ppm H2S. The obtained catalytic performances were compared with those of an Ir/CeO2 catalyst prepared by incipient wetness impregnation (IWI). The influence of the support and the metal was investigated through testing of Ir/SiO2-Al2O3-IWI and Rh-CeO2-SCS catalysts, respectively. Using CeO2 as carrier, Ir-based catalysts are highly efficient in SRM and resistant to carbon and irreversible sulfur poisoning. The catalytic activity of Ir-CeO2-SCS is superior to that of Ir/CeO2-IWI. Unlike the Ir-CeO2 catalyst, Ir/SiO2-Al2O3 is completely deactivated in presence of sulfur, while Rh-CeO2-SCS does not recover its initial activity after exposure to an H2S-containing feed. (C) 2014 Elsevier B.V. All rights reserved.

Published
2015

18. Insight into Organometallic Intermediate and Its Evolution to Covalent Bonding in Surface-Confined Ullmann Polymerization

Author

Mohamed El Garah, Albano Cossaro, Alberto Verdini, Dmitrii F. Perepichka, Luis Cardenas, Yannick Fagot Revurat, Josh Lipton-Duffin, Marco Di Giovannantonio, Vincent Meunier, Giorgio Contini, Federico Rosei, Istituto di Struttura della Materia ( CNR-ISM ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Énergie Matériaux Télécommunications - INRS ( EMT-INRS ), Institut National de la Recherche Scientifique [Québec] ( INRS ) -Université du Québec à Montréal ( UQAM ), Department of Physics, Applied Physics, and Astronomy [Troy], Rensselaer Polytechnic Institute ( RPI ), Center for Self-Assembled Chemical Structures ( CSACS ), Center for Self-Assembled Chemical Structures, Institut Jean Lamour ( IJL ), Université de Lorraine ( UL ) -Centre National de la Recherche Scientifique ( CNRS ), CNR - Istituto Officina dei Materiali ( IOM ), Department of Physics [Roma], Università degli Studi di Roma Tor Vergata [Roma], Istituto di Struttura della Materia (CNR-ISM), Consiglio Nazionale delle Ricerche [Roma] (CNR), Énergie Matériaux Télécommunications - INRS (EMT-INRS), Institut National de la Recherche Scientifique [Québec] (INRS)-Université du Québec à Montréal = University of Québec in Montréal (UQAM), Rensselaer Polytechnic Institute (RPI), Center for Self-Assembled Chemical Structures (CSACS), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), CNR Istituto Officina dei Materiali (IOM), and Department of Physics [Roma Tor Vergata]

Subjects
Materials science, [ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, law.invention, Ullmann coupling, X-ray photoelectron spectroscopy, law, Phenylene, conjugated polymers, General Materials Science, poly(para-phenylene) (PPP), Spectroscopy, fast X-ray photoelectron spectroscopy (fast-XPS), Low-energy electron diffraction, scanning tunneling microscopy (STM), General Engineering, 021001 nanoscience & nanotechnology, XANES, 0104 chemical sciences, Polymerization, Covalent bond, near-edge X-ray absorption fine structure spectroscopy (NEXAFS), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Scanning tunneling microscope, 0210 nano-technology, surface polymerization
Abstract

Équipe 102 : Surfaces et Spectroscopies; International audience; We provide insight into surface-catalyzed dehalogenative polymerization, analyzing the organometallic intermediate and its evolution into planar polymeric structures. A combined study using scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and first-principles calculations unveils the structural conformation of substrate-bound phenylene intermediates generated from 1,4-dibromobenzene precursors on Cu(110), showing the stabilizing role of the halogen. The appearance of covalently bonded conjugated structures is followed in real time by fast-XPS measurements (with an acquisition time of 2 s per spectrum and heating rate of 2 K/s), showing that the detaching of phenylene units from the copper substrate and subsequent polymerization occur upon annealing above 460 +/- 10 K.

Published
2013

19. Synthesis and electronic structure of a two dimensional pi-conjugated polythiophene

Author

Martin Vondráček, Jaclyn L. Brusso, Yannick Fagot-Revurat, Daniel Malterre, Laurentiu E. Dinca, Chaoying Fu, Dmitrii F. Perepichka, Josh Lipton-Duffin, Rico Gutzler, Federico Rosei, Luis Cardenas, Énergie Matériaux Télécommunications - INRS (EMT-INRS), Institut National de la Recherche Scientifique [Québec] (INRS)-Université du Québec à Montréal = University of Québec in Montréal (UQAM), Center for Self-Assembled Chemical Structures (CSACS), Center for Self-Assembled Chemical Structures, Institute of Physics of the Czech Academy of Sciences (FZU / CAS), Czech Academy of Sciences [Prague] (CAS), Sincrotrone Trieste, Italy, Sincrotrone Trieste, Institut Jean Lamour (IJL), and Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Materials science, Fermi level, 02 engineering and technology, General Chemistry, Polymer, Electronic structure, Conjugated system, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, symbols.namesake, Monomer, chemistry, Polymerization, X-ray photoelectron spectroscopy, symbols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Polythiophene, 0210 nano-technology
Abstract

Équipe 102 : Surfaces et Spectroscopies; International audience; We report the synthesis and first electronic characterization of an atomically thin two dimensional pi-conjugated polymer. Polymerization via Ullmann coupling of a tetrabrominated tetrathienoanthracene on Ag(111) in ultra-high vacuum (UHV) produces a porous 2D polymer network that has been characterized by scanning tunnelling microscopy (STM). High-resolution X-ray photoelectron spectroscopy (HRXPS) shows that the reaction proceeds via two distinct steps: dehalogenation of the brominated precursor, which begins at room temperature (RT), and C-C coupling of the resulting Ag-bound intermediates, which requires annealing at 300 degrees C. The formation of the 2D conjugated network is accompanied by a shift of the occupied molecular states by 0.6 eV towards the Fermi level, as observed by UV photoelectron spectroscopy (UPS). A theoretical analysis of the electronic gap reduction in the transition from monomeric building blocks to various 1D and 2D oligomers and polymers yields important insight into the effect of topology on the electronic structure of 2D conjugated polymers.

Published
2013

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