20 results on '"Koneti, Siddardha"'
Search Results
2. Active phases for high temperature Fischer-Tropsch synthesis in the silica supported iron catalysts promoted with antimony and tin
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Peron, Deizi V., Barrios, Alan J., Taschin, Alan, Dugulan, Iulian, Marini, Carlo, Gorni, Giulio, Moldovan, Simona, Koneti, Siddardha, Wojcieszak, Robert, Thybaut, Joris W., Virginie, Mirella, and Khodakov, Andrei Y.
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- 2021
- Full Text
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3. Preparation of hierarchical SSZ-13 by NH4F etching
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Babić, Viktoria, Koneti, Siddardha, Moldovan, Simona, Nesterenko, Nikolai, Gilson, Jean-Pierre, and Valtchev, Valentin
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- 2021
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4. Bismuth mobile promoter and cobalt-bismuth nanoparticles in carbon nanotube supported Fischer-Tropsch catalysts with enhanced stability
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Gu, Bang, Peron, Deizi V., Barrios, Alan J., Virginie, Mirella, La Fontaine, Camille, Briois, Valérie, Vorokhta, Mykhailo, Šmíd, Břetislav, Moldovan, Simona, Koneti, Siddardha, Gambu, Thobani G., Saeys, Mark, Ordomsky, Vitaly V., and Khodakov, Andrei Y.
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- 2021
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5. Carbon-based catalysts for Fischer–Tropsch synthesis
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Ordomsky, Vitaly, Wang, Qiyan, Zhou, Wen-Juan, Heyte, Svetlana, Thuriot-Roukos, Joëlle, Marinova, Maya, Addad, Ahmed, Rouzière, Stéphan, Simon, Pardis, Capron, Mickael, Zhang, Linjie, Grimaud, Alexis, Schwiedernoch, Renate, Hernández, Willinton Yesid, Naghavi, Negar, Pedrolo, Débora, Schwaab, Marcio, Marcilio, Nilson, Khodakov, Andrei, Santos, Sara, Urbina-Blanco, César, Zhou, Wenjuan, Yang, Yong, Joelle, Thuriot-Roukos, Ersen, Ovidiu, Baaziz, Walid, Safonova, Olga, Saeys, Mark, Gu, Bang, Peron, Deizi, Barrios, Alan, Virginie, Mirella, La Fontaine, Camille, Briois, Valérie, Vorokhta, Mykhailo, Šmíd, Břetislav, Moldovan, Simona, Koneti, Siddardha, Gambu, Thobani, Hernández, Willinton, Impéror-Clerc, Marianne, Vovk, Evgeny, Wu, Dan, Nuns, Nicolas, Palčić, Ana, Jaén, Sara Navarro, Cai, Mengdie, Liu, Chong, Pidko, Evgeny, Valtchev, Valentin, Yan, Zhen, Zhang, Songwei, Li, Jerry Pui Ho, Zhao, Jingpeng, Yuan, Biao, He, Tao, Yu, Yi, Li, Tao, Hu, Di, Chen, Yanping, Wei, Jiatong, Duyar, Melis, Liu, Jian, Dalian Institute of Chemical Physics - Chinese Academy of Sciences, University of Surrey (UNIS), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), ANR-16-CE06-0013,NANO4FuT,Synthèse des carburants alternatifs et des molécules plateforme sur nanoréacteurs(2016), CNRS, Centrale Lille, ENSCL, Univ. Artois, Université de Lille, Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181, Ordomsky, Vitaly, Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Eco-Efficient Products &Processes Laboratory (E2PL2), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-RHODIA, Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Institut Michel Eugène Chevreul - FR 2638 (IMEC), Université d'Artois (UA)-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centrale Lille Institut (CLIL), Unité Matériaux et Transformations - UMR 8207 (UMET), Institut de Chimie du CNRS (INC)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Laboratoire de Physique des Solides (LPS), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Chimie du solide et de l'énergie (CSE), Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Solvay (France), Instituto Federal do Rio Grande do Sul (IFRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Paul Scherrer Institute (PSI), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Charles University [Prague] (CU), Groupe de physique des matériaux (GPM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Ruđer Bošković Institute (IRB), Delft University of Technology (TU Delft), Laboratoire catalyse et spectrochimie (LCS), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Université de Caen Normandie (UNICAEN), ShanghaiTech University [Shanghai], Beihang University (BUAA), School of Physics Science and Engineering, Tongji University, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Eco-Efficient Products & Processes Laboratory (E2P2L), RHODIA-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)
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Materials science ,chemistry.chemical_element ,02 engineering and technology ,Carbon nanotube ,010402 general chemistry ,01 natural sciences ,7. Clean energy ,law.invention ,Catalysis ,law ,[CHIM] Chemical Sciences ,medicine ,[CHIM]Chemical Sciences ,Coal ,Gasoline ,Carbon nanofiber ,business.industry ,Fischer–Tropsch process ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Chemical engineering ,chemistry ,0210 nano-technology ,business ,Carbon ,Activated carbon ,medicine.drug - Abstract
International audience; Fischer-Tropsch synthesis (FTS) is an essential approach to convert coal, biomass, and shale gas into fuels and chemicals, such as lower olefins, gasoline, diesel, and so on. In recent years, there has been increasing motivation to deploy FTS at commercial scales which has been boosting the discovery of high performance catalysts. In particular, the importance of support in modulating the activity of metals has been recognized and carbonaceous materials have attracted attention as supports for FTS. In this review, we summarised the substantial progress in the preparation of carbon-based catalysts for FTS by applying activated carbon (AC), carbon nanotubes (CNTs), carbon nanofibers (CNFs), carbon spheres (CSs), and metal-organic frameworks (MOFs) derived carbonaceous materials as supports. A general assessment of carbon-based catalysts for FTS, concerning the support and metal properties, activity and products selectivity, and their interactions is systematically discussed. Finally, current challenges and future trends in the development of carbon-based catalysts for commercial utilization in FTS are proposed.
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- 2021
6. Very Fast Acquisition of Tilt series in Environmental TEM Tomography: Tips and Tricks
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Epicier, Thierry, Grenier, Thomas, Banjak, Hussein, Maxim, Voichita, Koneti, Siddardha, Roiban, Lucian, 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), Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Société Française des Microscopies (SFµ), ANR-05-PADD-0003,TRANS,Transformations de l'élevage et dynamiques des espaces(2005), Epicier, Thierry, Programme fédérateur Agriculture et Développement Durable - Transformations de l'élevage et dynamiques des espaces - - TRANS2005 - ANR-05-PADD-0003 - ADD - VALID, and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
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fast tomography ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,environmental electron tomography ,[SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing ,[PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,[SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing - Abstract
National audience; In environmental Transmission Electron Microscopy (ETEM), nanomaterials can be studied under dynamic conditions in a gaseous or liquid environment. An important challenge is to track their evolution in 3D. Intuitively, the acquisition of the tomographic tilt series must be completed in a very short time to prevent any morphological modification due to irradiation and/or dynamic change of the object during its rotation for allowing a relevant volume reconstruction.Recently we have demonstrated than Bright Field (BF) tomography can be performed in a few minutes in an environmental microscope (FEI-TITAN ETEM, 80-300 kV) [1,2]. With the help of fast recording (CMOS or direct electron) cameras capable of acquiring tens or hundreds fps in at least a (2k)² format, acquiring a tilt series during a continuous rotation of the sample without any stop can be completed in only a few seconds. Typical examples on nano-catalysts or electron beam sensitive materials will be reported of tomography acquisitions performed over a tilt amplitude of 140° in short times, down to 5-6 seconds under environmental, e.g. temperature and gas conditions (figure 1). However, several remaining problems must be addressed, like diffraction contrast, blur effects, low SNR. One of the most severe limitations is the imperfect rotation of the goniometer, which lead to systematic drifts of the sample up to the frequent exit of the projection out of the field of view. We will describe a robust solution consisting in a fast computer-routine compatible with a TITAN microscope equipped with a Gatan Oneview camera using the ‘in-situ’ option (figure 2).
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- 2019
7. 2D and Fast 3D in situ study of the calcination and reduction of Pd nanocatalysts supported on Alumina in Environmental Transmission Electron Microscopy (ETEM)
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Epicier, Thierry, Koneti, Siddardha, Roiban, Lucian, Gay, Anne-Sophie, Cabiac, Amandine, Avenier, Priscilla, 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), IFP Energies nouvelles (IFPEN), Direction Catalyse et séparation, IFP Energies nouvelles (IFPEN)-IFP Energies nouvelles (IFPEN), ANR-05-PADD-0003,TRANS,Transformations de l'élevage et dynamiques des espaces(2005), Epicier, Thierry, and Programme fédérateur Agriculture et Développement Durable - Transformations de l'élevage et dynamiques des espaces - - TRANS2005 - ANR-05-PADD-0003 - ADD - VALID
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[CHIM.MATE] Chemical Sciences/Material chemistry ,operando TEM ,ETEM ,heterogeneous catalysis ,Environmental Transmission Electron Microscopy ,Pd-Al2O3 ,[CHIM.CATA] Chemical Sciences/Catalysis ,[CHIM.CATA]Chemical Sciences/Catalysis ,[CHIM.MATE]Chemical Sciences/Material chemistry - Abstract
International audience; 2D AND FAST 3D IN SITU CALCINATION AND REDUCTION OF Pd NANOCATALYSTS SUPPORTED ON ALUMINA IN ENVIRONMENTAL TRANSMISSION ELECTRON MICROSCOPYThierry Epicier1, Siddardha Koneti1, Lucian Roiban1, Anne-Sophie Gay2, Priscilla Avenier21Université de Lyon, MATEIS, INSA de Lyon, UCB Lyon 1, UMR 5510 CNRS, 69621 Villeurbanne Cedex, France2IFP Energies nouvelles, Rond-point de l'échangeur de Solaize, BP 3, 69360 Solaize, FranceEnvironmental Transmission Electron Microscopy (ETEM) has recently open the way to operando studies of nanomaterials down to the atomic resolution in temperature and under a gaseous atmosphere that may reproduce more or less its real environmental conditions of use for real applications [1]. This is especially relevant in the field of nanoparticles (NPs) used in heterogeneous catalysis. The present work concerns the dynamic evolution of Pd small NPs (1-3 nm in size) supported on delta-Al2O3 platelets during the catalysis preparation process. This system has important applications, for example in petrochemistry or environmental catalysis. The calcination and reduction steps are followed under O2 and H2 up to 500°C in a FEI TITAN-ETEM microscope operated at 300 kV. Nowadays attention is paid to the “identical location” approach in TEM [2], where the same Region of Interest (ROI) is studied ‘before’ and ‘after’ a solicitation (heat treatment, exposure to gas…) performed outside the microscope. Typical results will show that this strategy is implicit in ETEM: the same ROI is naturally tracked at any stage during its dynamic evolution. One of the main key features insuring the catalytic efficiency of NPs is their resistance to sintering and their ability to remain homogeneously distributed during the calcination and reduction processes. The first point has been quantified through size measurements at different stages of the preparation process. The second point requires evaluating the localization of NPs in 3D using Electron Tomography (ET). Conventional ET, either in the Scanning or Bright Field TEM modes, consists in acquiring 2D projections over a large angular range, a time-consuming process hardly compatible with an in situ approach. We have thus developed a fast ET procedure [3] allowing rapid acquisitions of tilt series for volume reconstruction in only 1 or 2 minutes and a few seconds in the best cases [4]. Therefore, several tomograms of the same area are recorded in situ without critical irradiation damage of the sample shortly exposed to the electron beam. Typical examples will be shown including statistical distribution parameters, such as the inter-NPs distances measured in different states [5]. [1] ‘Controlled Atmosphere Transmission Electron Microscopy’, ed. T.W. Hansen, J.B. Wagner, Springer, New York (2016) 332 p.[2] K.J.J. Mayrhofer et al., Chem. Comm. 10 (2008) 1144-1147.[3] L. Roiban et al., J. of Microscopy, 269 (2018) 117-126.[4] H. Banjak et al., Ultramicroscopy, 189 (2018) 109-123.[5] CLYM (www.clym.fr) is acknowledged for access to the ETEM which was financially supported by the CNRS, the Région Rhône-Alpes, the ‘GrandLyon’ and the French Ministry of Research and Higher Education. This work is supported by the French National Research Agency ANR (3DCLEAN project n°15-CE09-0009-01).
- Published
- 2018
8. Microscopie électronique à transmission in situ et 3d environnementale de nano-catalyseurs Pd-Al2O3 : Tomographie rapide avec applications à d'autres systèmes catalytiques dans des conditions d'exploitation et à des nanomatériaux sensibles au faisceau d'électrons
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Koneti, Siddardha, 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), Université de Lyon, and Thierry Epicier
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Heterogeneous catalysis ,Electron tomography ,Tomographie électronique ,Transmission Electron Microscopy ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Catalyse hétérogène ,Nanomateriaux ,Microscopie électronique en transmission ,Nanomaterials - Abstract
In the beginning of the XXIst century, Environmental Transmission Electron Microscopy has become one of the reliable characterization techniques of nanomaterials in conditions mimicking their real life. ETEM is now able to follow the dynamic evolution of nanomaterials under various conditions like high temperature, liquid or various gas pressures. Among various fields of research, catalysis can benefit significantly from Environmental Microscopy. This contribution starts with the study of the Palladium-Alumina catalytic system. Pd nanoparticles supported by α-Al2O3 and δ-Al2O3 are of an important physicochemical and environmental interest, particularly in the field of selective hydrogenation in petrochemistry, for the synthesis of polymers or CO2 hydrogenation for methane production. We first performed 2D analyses at different steps of the synthesis process, then the same synthesis steps were performed under in situ conditions. The motivation of this approach was to compare post mortem treatments with ETEM observations. In general, 2D data provide limited insights on, for example, the morphology and position of supported nanoparticles. We have then developed a new fast acquisition approach to collect tomographic tilt series in very short times, enabling to reconstruct nano-systems in 3D during their dynamical evolution. Taking advantage of this approach, we have determined the activation energy for soot combustion on YSZ oxidation catalysts for diesel motors from volumetric data extracted from in situ experiments. Fast electron tomography was also applied to electron beam sensitive materials, like polymer nanocomposites and biological materials, showing the wide spectrum of possible applications for rapid 3D characterization of nanomaterials.; Au début du XXIème siècle, la Microscopie Electronique à Transmission en mode Environnemental (ETEM) est devenue l’une des techniques les plus fiables de caractérisation de nanomatériaux dans des conditions simulant leur vie réelle. L’ETEM est maintenant en mesure de suivre l’évolution dynamique des nanomatériaux dans des conditions variables comme l’exposition à des températures élevées, l’observation en milieux liquide ou gazeux à diverses pressions. Parmi différents domaines de recherche et développement concernés, la catalyse peut bénéficier de manière significative des avancées permises par la microscopie électronique environnementale. Cette thèse, dédiée au développement de l’ETEM au laboratoire MATEIS, a commencé avec l’étude du système catalytique Pd-alumine. Les nanoparticules de Pd déposées sur alpha -Al2O3 et delta-Al2O3 sont très utilisées en physicochimie avec un impact environnemental important : en particulier dans le domaine de l’hydrogénation sélective, pour la synthèse de polymères ou l’hydrogénation de CO2 pour la production de méthane. Nous avons tout d’abord effectué des analyses 2D aux différentes étapes du processus de synthèse du catalyseur : imprégnation du précurseur, séchage et chauffage pour la calcination dans l’air à la pression atmosphérique. La motivation de cette approche a été de comparer des analyses post mortem avec des traitements en ETEM où l’évolution des nanoparticules peut être mesurée in situ et pas seulement « avant » et « après ». De manière générale, les études faites en ETEM en 2D donnent un aperçu limité sur la morphologie des objets et la distribution spatiale des nanoparticules supportées. Nous avons développé une nouvelle approche d’acquisition rapide pour collecter dans des temps très courts des séries d’images sous différents angles de vue pour la tomographie électronique, la rapidité de cette acquisition étant un prérequis pour appréhender correctement la morphologie d’un nano-système au cours de son évolution dynamique in situ. La technique a ensuite été utilisée pour l’étude de plusieurs systèmes où une acquisition tridimensionnelle rapide est indispensable, notamment sur un sujet concernant un enjeu sociétal important, la dépollution des moteurs diesel : l’oxydation de la suie a été étudiée in situ sur des supports à base de zircone entre 400 et 600°C et une pression de 2 mbar d’oxygène à différents degrés de combustion, ce qui a permis d’extraire des données cinétiques telle que l’énergie d’activation du processus. La tomographie électronique rapide a été également appliquée à des matériaux sensibles au faisceau électronique, comme des nanocomposites polymères et des objets biologiques, montrant le large spectre d’applications possibles pour cette technique, qui constitue un pas important vers la caractérisation operando 3D de nanomatériaux en temps réel.
- Published
- 2017
9. In situ and 3D environmental transmission electron microscopy of Pd-Al2O3 nano catalysts : Fast tomography with applications to other catalytic systems in operando conditions and to electron beam sensitive nanomaterials
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Koneti, Siddardha, STAR, ABES, 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), Université de Lyon, and Thierry Epicier
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Heterogeneous catalysis ,[CHIM.MATE] Chemical Sciences/Material chemistry ,Electron tomography ,Tomographie électronique ,Transmission Electron Microscopy ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Nanomateriaux ,Catalyse hétérogène ,Microscopie électronique en transmission ,Nanomaterials - Abstract
In the beginning of the XXIst century, Environmental Transmission Electron Microscopy has become one of the reliable characterization techniques of nanomaterials in conditions mimicking their real life. ETEM is now able to follow the dynamic evolution of nanomaterials under various conditions like high temperature, liquid or various gas pressures. Among various fields of research, catalysis can benefit significantly from Environmental Microscopy. This contribution starts with the study of the Palladium-Alumina catalytic system. Pd nanoparticles supported by α-Al2O3 and δ-Al2O3 are of an important physicochemical and environmental interest, particularly in the field of selective hydrogenation in petrochemistry, for the synthesis of polymers or CO2 hydrogenation for methane production. We first performed 2D analyses at different steps of the synthesis process, then the same synthesis steps were performed under in situ conditions. The motivation of this approach was to compare post mortem treatments with ETEM observations. In general, 2D data provide limited insights on, for example, the morphology and position of supported nanoparticles. We have then developed a new fast acquisition approach to collect tomographic tilt series in very short times, enabling to reconstruct nano-systems in 3D during their dynamical evolution. Taking advantage of this approach, we have determined the activation energy for soot combustion on YSZ oxidation catalysts for diesel motors from volumetric data extracted from in situ experiments. Fast electron tomography was also applied to electron beam sensitive materials, like polymer nanocomposites and biological materials, showing the wide spectrum of possible applications for rapid 3D characterization of nanomaterials., Au début du XXIème siècle, la Microscopie Electronique à Transmission en mode Environnemental (ETEM) est devenue l’une des techniques les plus fiables de caractérisation de nanomatériaux dans des conditions simulant leur vie réelle. L’ETEM est maintenant en mesure de suivre l’évolution dynamique des nanomatériaux dans des conditions variables comme l’exposition à des températures élevées, l’observation en milieux liquide ou gazeux à diverses pressions. Parmi différents domaines de recherche et développement concernés, la catalyse peut bénéficier de manière significative des avancées permises par la microscopie électronique environnementale. Cette thèse, dédiée au développement de l’ETEM au laboratoire MATEIS, a commencé avec l’étude du système catalytique Pd-alumine. Les nanoparticules de Pd déposées sur alpha -Al2O3 et delta-Al2O3 sont très utilisées en physicochimie avec un impact environnemental important : en particulier dans le domaine de l’hydrogénation sélective, pour la synthèse de polymères ou l’hydrogénation de CO2 pour la production de méthane. Nous avons tout d’abord effectué des analyses 2D aux différentes étapes du processus de synthèse du catalyseur : imprégnation du précurseur, séchage et chauffage pour la calcination dans l’air à la pression atmosphérique. La motivation de cette approche a été de comparer des analyses post mortem avec des traitements en ETEM où l’évolution des nanoparticules peut être mesurée in situ et pas seulement « avant » et « après ». De manière générale, les études faites en ETEM en 2D donnent un aperçu limité sur la morphologie des objets et la distribution spatiale des nanoparticules supportées. Nous avons développé une nouvelle approche d’acquisition rapide pour collecter dans des temps très courts des séries d’images sous différents angles de vue pour la tomographie électronique, la rapidité de cette acquisition étant un prérequis pour appréhender correctement la morphologie d’un nano-système au cours de son évolution dynamique in situ. La technique a ensuite été utilisée pour l’étude de plusieurs systèmes où une acquisition tridimensionnelle rapide est indispensable, notamment sur un sujet concernant un enjeu sociétal important, la dépollution des moteurs diesel : l’oxydation de la suie a été étudiée in situ sur des supports à base de zircone entre 400 et 600°C et une pression de 2 mbar d’oxygène à différents degrés de combustion, ce qui a permis d’extraire des données cinétiques telle que l’énergie d’activation du processus. La tomographie électronique rapide a été également appliquée à des matériaux sensibles au faisceau électronique, comme des nanocomposites polymères et des objets biologiques, montrant le large spectre d’applications possibles pour cette technique, qui constitue un pas important vers la caractérisation operando 3D de nanomatériaux en temps réel.
- Published
- 2017
10. Novel Strategy for the Synthesis of Ultra‐Stable Single‐Site Mo‐ZSM‐5 Zeolite Nanocrystals.
- Author
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Konnov, Stanislav V., Dubray, Florent, Clatworthy, Edwin B., Kouvatas, Cassandre, Gilson, Jean‐Pierre, Dath, Jean‐Pierre, Minoux, Delphine, Aquino, Cindy, Valtchev, Valentin, Moldovan, Simona, Koneti, Siddardha, Nesterenko, Nikolai, and Mintova, Svetlana
- Subjects
NANOCRYSTALS ,POINT defects ,MICROSCOPY ,ZEOLITES ,ENERGY level transitions - Abstract
The current energy transition presents many technological challenges, such as the development of highly stable catalysts. Herein, we report a novel "top‐down" synthesis approach for preparation of a single‐site Mo‐containing nanosized ZSM‐5 zeolite which has atomically dispersed framework‐molybdenum homogenously distributed through the zeolite crystals. The introduction of Mo heals most of the native point defects in the zeolite structure resulting in an extremely stable material. The important features of this single‐site Mo‐containing ZSM‐5 zeolite are provided by an in‐depth spectroscopic and microscopic analysis. The material demonstrates superior thermal (up to 1000 °C), hydrothermal (steaming), and catalytic (converting methane to hydrogen and higher hydrocarbons) stability, maintaining the atomically disperse Mo, structural integrity of the zeolite, and preventing the formation of silanols. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
11. Highly ductile amorphous oxide at room temperature and high strain rate.
- Author
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Frankberg, Erkka J., Kalikka, Janne, Ferré, Francisco García, Joly-Pottuz, Lucile, Salminen, Turkka, Hintikka, Jouko, Hokka, Mikko Hokka, Koneti, Siddardha, Douillard, Thierry, Le Saint, Bérangère, Kreiml, Patrice, Cordill, Megan J., Epicier, Thierry, Stauffer, Douglas, Vanazzi, Matteo, Roiban, Lucian, Akola, Jaakko, Di Fonzo, Fabio, Levänen, Erkki, and Masenelli-Varlot, Karine
- Published
- 2019
- Full Text
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12. Selective Wet Etching of Silicon Germanium in Composite Vertical Nanowires.
- Author
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Baraissov, Zhaslan, Pacco, Antoine, Koneti, Siddardha, Bisht, Geeta, Panciera, Federico, Holsteyns, Frank, and Mirsaidov, Utkur
- Published
- 2019
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13. 2D & 3D in situ study of the calcination of Pd nanocatalysts supported on delta-Alumina in an Environmental Transmission Electron Microscope.
- Author
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Epicier, Thierry, Koneti, Siddardha, Avenier, Priscilla, Cabiac, Amandine, Gay, Anne-Sophie, and Roiban, Lucian
- Subjects
- *
TRANSMISSION electron microscopes , *HIGH resolution imaging , *OSTWALD ripening , *DIAGNOSTIC imaging , *TRANSMISSION electron microscopy , *HETEROGENEOUS catalysis - Abstract
• The genesis of Pd nanocatalysts on Al 2 O 3 can be adequately followed by in situ ETEM. • Fast tomography in ETEM unravels the 3D evolution of NPs during calcination. • Oxidation and reduction of Pd NPs is followed down to the atomic scale in ETEM. • In situ tracking of Pd NPs in ETEM evidences that they grow by Ostwald Ripening. The quality of metallic nanoparticles (NPs) used in heterogeneous catalysis relies through many aspects on their small size, on the homogeneity of their spatial distribution on their supports and on their ability to resist to sintering or coalescence. It is thus very important to quantify these parameters and understand the mechanisms controlling the growth of NPs during the genesis process of the catalyst. Whereas conventional Transmission Electron Microscopy (TEM) is currently used for these purposes, it most frequently remains a 'static' method where results are obtained in high vacuum and post mortem, i.e. after the typical drying, calcination and reduction steps without the possibility to follow directly the evolution of both NPs and supports during those treatments. Environmental TEM (ETEM) unlocks this blocking and allows elementary mechanisms, such as Ostwald Ripening and coalescence to be unravelled through direct in situ observations. We report here an ETEM study of the preparation of Pd-based narrow NPs, less than 5 nm in size, deposited on a δ-alumina support. We focused on 3 main objectives: (i) quantifying the sizes of NPs at each preparation step performed in situ under environmental (i.e. respectively oxygen or air and hydrogen atmospheres at working temperatures) and comparing them to post mortem measurements; (ii) identify the oxidation state of the NPs through an in situ High Resolution imaging study of their crystallographic structure; (iii) explore the possibilities of environmental tri-dimensional (3D) studies by tilt series based Electron Tomography. This last item represents a challenging breakthrough in the characterization of nanocatalysts; it will be demonstrated that the use of modern instruments (microscope and accessories) allows tomographic acquisitions to be performed very fast, within a few minutes and even seconds, which opens the way to the 3D tracking of microstructures almost in real time during their evolution under gas and at high temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. Fast electron tomography: Applications to beam sensitive samples and in situ TEM or operando environmental TEM studies.
- Author
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Koneti, Siddardha, Roiban, Lucian, Dalmas, Florent, Langlois, Cyril, Gay, Anne-Sophie, Cabiac, Amandine, Grenier, Thomas, Banjak, Hussein, Maxim, Voichiţa, and Epicier, Thierry
- Subjects
- *
ELECTRON beams , *ENVIRONMENTAL sciences , *TRANSMISSION electron microscopes , *POLYMERIC nanocomposites , *TOMOGRAPHY , *BIOMATERIALS - Abstract
Electron Tomography (ET) is of greatest interest in studying nano- and biological materials since it gives access to 3D morphological, chemical and physical features. Even though ET techniques have been continuously improved in the last decades, they are still limited: lengthy time scales (tens of minutes) are generally needed for the tilt series acquisition prior to the volume reconstruction step. Such long exposures to a relatively intense electron beam lead to large electron doses received by the sample. This may promote extensive irradiation damage in the case of soft materials like polymers and bio-materials when they are not protected through dedicated sample preparation methods, and any tomographic reconstruction will then be meaningless. More importantly, the time constraints drastically limit 3D investigations during dynamic in-situ experiments where the sample rapidly evolves during the acquisition. We present here developments for acquiring tilt series of projections in very short time scales, readily down to a few seconds. After an outlook of possible ways to speed up the data acquisition in the bright field imaging mode (BF-TEM), strategies for the fastest methods in 'step-by-step' and 'continuous tilt' ET will be described. Applications of these procedures are presented on various systems, including metallic Pd nanoparticles deposited on alumina, and soft materials like polymer nanocomposites and biological matter. A special reference is made to fast operando nano-tomography performed on nanomaterials during their dynamic evolution. The feasibility of fast ET is exemplified by a calcination study of Pd catalysts supported by SiO 2 at 400 °C and 500 °C under 4 mbar H 2 in a dedicated Environmental Transmission Electron Microscope (ETEM). Unlabelled Image • Fast image acquisition for Electron Tomography (ET) can take only a few seconds. • A continuous rotation of the sample allows relevant and fast acquisition for ET. • Fast ET is possible under gas and temperature conditions in-situ in a ETEM. • Repeated acquisitions on the same object allow to follow its evolution in operando. • The resistance to sintering of Pd@SiO 2 nanocatalyst is quantified in situ in 3D. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. Uncovering the 3 D Structure of Combustion-Synthesized Noble Metal-Ceria Nanocatalysts.
- Author
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Roiban, Lucian, Koneti, Siddardha, Morfin, Franck, Nguyen, Thanh‐Son, Mascunan, Pascale, Aouine, Mimoun, Epicier, Thierry, and Piccolo, Laurent
- Subjects
- *
METAL nanoparticles , *CERIUM oxides , *GLYCINE , *SCANNING transmission electron microscopy , *PLATINUM nanoparticles - Abstract
With its unique redox properties, ceria is an oxide with a range of applications, including automotive catalytic converters, which consist of platinum-group metal nanoparticles on ceria-containing supports. In this work, the 3 D architecture of a ceria-based material synthesized by the widely employed glycine-nitrate solution combustion method is revealed for the first time. Together with N2 adsorption volumetry, scanning transmission electron microscopy (STEM) and scanning electron microscopy (SEM), STEM tomography provides a comprehensive picture of the multimodal porous network of a pre-reduced Pt-CeO2 catalyst, from the nanometer to the micrometer scale. This material consists of ceria nanocrystallites forming 3 D aggregates and puzzle-like 2 D walls separating large roundish mesopores and macropores. The small voids between imperfectly assembled crystallites give rise to some microporosity. In addition, it is demonstrated that a significant proportion of platinum nanoparticles (3-4 nm) are not located at the ceria surface following the one-step synthesis process, about half of them are buried within ceria. This result is valid for another metal (Rh) and another fuel (oxalyl dihydrazide), and has important implications for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
16. Three dimensional analysis of nanoporous silicon particles for Li-ion batteries.
- Author
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Roiban, Lucian, Koneti, Siddardha, Wada, Takeshi, Kato, Hidemi, Cadete Santos Aires, Francisco J., Curelea, Sergiu, Epicier, Thierry, and Maire, Eric
- Subjects
- *
NANOPOROUS materials , *LITHIUM-ion batteries , *PHYSISORPTION , *LITHIATION , *CHEMICAL processes - Abstract
Bulk nanoporous silicon prepared by top-down method form Li-ion batteries was investigated combining different conventional technique such as nitrogen physisorption and high resolution electron microscopy with electron tomography. It was found that the Si nanorods are forming porous aggregates with a half of the volume of the particle occupied by pores. The nanorods are preferentially oriented along the main axis of the aggregate. The porosity and the lack of compaction between the aggregates provide space for the Si expansion during the lithiation process. It was found that the Si nanorods mainly expose the {111} family plane as an external faces. The size distributions of the porous and solid phases in a granule were found to be similar. The pores represent 50% of the total volume of an aggregate. The shape orientation of the particles was quantified and it was found to exhibit a narrow distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
17. Chromic acid dealumination of zeolites.
- Author
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Babić, Viktoria, Koneti, Siddardha, Moldovan, Simona, Debost, Maxime, Gilson, Jean-Pierre, and Valtchev, Valentin
- Subjects
- *
CHROMIC acid , *CONCENTRATION functions , *X-ray diffraction , *PHYSISORPTION - Abstract
Commercial zeolites with CHA, MFI, and LTL framework topology are subjected to acid treatment with chromic acid (H 2 CrO 4) solutions with concentrations ranging between 0.1 and 10 w /%. As chromic acid forms polymeric species as a function of concentration, specific effects are obtained with these three zeolites, differing by their framework topology, pore size, Si/Al ratios and crystal size. The etched zeolites are characterized by X-ray diffraction, SEM, TEM, N 2 physisorption, ICP-AES, 27Al and 29Si MAS NMR, 29Si{1H} cross-polarization spectra, EDX. Their acidic properties are probed with pyridine and d 3 -acetonitrile by in situ FTIR. Results indicate that the 8 MR (CHA) and 10 MR (MFI) zeolites are more resistant to acid treatment with chromic acid than the 12 MR (LTL) zeolite. This paves the way for rational control of zeolite dealumination since adjusting chromic acid concentration will generate anions appropriate for treating a particular zeolite. [Display omitted] • CHA, MFI, and LTL zeolites are subjected to treatment with chromic acid (H 2 CrO 4). • Chromic acid forms polymeric species as a function of concentration. • CHA and MFI zeolites resist more to the chromic acid treatment than the LTL zeolite. • Tuning the acid concentration yields anions apt for treating a particular zeolite. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Evaluation of noise and blur effects with SIRT-FISTA-TV reconstruction algorithm: Application to fast environmental transmission electron tomography.
- Author
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Banjak, Hussein, Grenier, Thomas, Epicier, Thierry, Koneti, Siddardha, Roiban, Lucian, Gay, Anne-Sophie, Magnin, Isabelle, Peyrin, Françoise, and Maxim, Voichita
- Subjects
- *
SCANNING laser ophthalmoscopy , *IMAGE segmentation , *MAGNETIC resonance imaging , *COMPUTED tomography , *DIGITAL image processing - Abstract
Fast tomography in Environmental Transmission Electron Microscopy (ETEM) is of a great interest for in situ experiments where it allows to observe 3D real-time evolution of nanomaterials under operating conditions. In this context, we are working on speeding up the acquisition step to a few seconds mainly with applications on nanocatalysts. In order to accomplish such rapid acquisitions of the required tilt series of projections, a modern 4K high-speed camera is used, that can capture up to 100 images per second in a 2K binning mode. However, due to the fast rotation of the sample during the tilt procedure, noise and blur effects may occur in many projections which in turn would lead to poor quality reconstructions. Blurred projections make classical reconstruction algorithms inappropriate and require the use of prior information. In this work, a regularized algebraic reconstruction algorithm named SIRT-FISTA-TV is proposed. The performance of this algorithm using blurred data is studied by means of a numerical blur introduced into simulated images series to mimic possible mechanical instabilities/drifts during fast acquisitions. We also present reconstruction results from noisy data to show the robustness of the algorithm to noise. Finally, we show reconstructions with experimental datasets and we demonstrate the interest of fast tomography with an ultra-fast acquisition performed under environmental conditions, i.e. gas and temperature, in the ETEM. Compared to classically used SIRT and SART approaches, our proposed SIRT-FISTA-TV reconstruction algorithm provides higher quality tomograms allowing easier segmentation of the reconstructed volume for a better final processing and analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
19. Novel Strategy for the Synthesis of Ultra-Stable Single-Site Mo-ZSM-5 Zeolite Nanocrystals.
- Author
-
Konnov SV, Dubray F, Clatworthy EB, Kouvatas C, Gilson JP, Dath JP, Minoux D, Aquino C, Valtchev V, Moldovan S, Koneti S, Nesterenko N, and Mintova S
- Abstract
The current energy transition presents many technological challenges, such as the development of highly stable catalysts. Herein, we report a novel "top-down" synthesis approach for preparation of a single-site Mo-containing nanosized ZSM-5 zeolite which has atomically dispersed framework-molybdenum homogenously distributed through the zeolite crystals. The introduction of Mo heals most of the native point defects in the zeolite structure resulting in an extremely stable material. The important features of this single-site Mo-containing ZSM-5 zeolite are provided by an in-depth spectroscopic and microscopic analysis. The material demonstrates superior thermal (up to 1000 °C), hydrothermal (steaming), and catalytic (converting methane to hydrogen and higher hydrocarbons) stability, maintaining the atomically disperse Mo, structural integrity of the zeolite, and preventing the formation of silanols., (© 2020 Wiley-VCH GmbH.)
- Published
- 2020
- Full Text
- View/download PDF
20. Electron Tomography of Plasmonic Au Nanoparticles Dispersed in a TiO 2 Dielectric Matrix.
- Author
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Koneti S, Borges J, Roiban L, Rodrigues MS, Martin N, Epicier T, Vaz F, and Steyer P
- Abstract
Plasmonic Au nanoparticles (AuNPs) embedded into a TiO
2 dielectric matrix were analyzed by combining two-dimensional and three-dimensional electron microscopy techniques. The preparation method was reactive magnetron sputtering, followed by thermal annealing treatments at 400 and 600 °C. The goal was to assess the nanostructural characteristics and correlate them with the optical properties of the AuNPs, particularly the localized surface plasmon resonance (LSPR) behavior. High-angle annular dark field-scanning transmission electron microscopy results showed the presence of small-sized AuNPs (quantum size regime) in the as-deposited Au-TiO2 film, resulting in a negligible LSPR response. The in-vacuum thermal annealing at 400 °C induced the formation of intermediate-sized nanoparticles (NPs), in the range of 10-40 nm, which led to the appearance of a well-defined LSPR band, positioned at 636 nm. Electron tomography revealed that most of the NPs are small-sized and are embedded into the TiO2 matrix, whereas the larger NPs are located at the surface. Annealing at 600 °C promotes a bimodal size distribution with intermediate-sized NPs embedded in the matrix and big-sized NPs, up to 100 nm, appearing at the surface. The latter are responsible for a broadening and a redshift, to 645 nm, in the LSPR band because of increase of scattering-to-absorption ratio. Beyond differentiating and quantifying the surface and embedded NPs, electron tomography also provided the identification of "hot-spots". The presence of NPs at the surface, individual or in dimers, permits adsorption sites for LSPR sensing and for surface-enhanced spectroscopies, such as surface-enhanced Raman scattering.- Published
- 2018
- Full Text
- View/download PDF
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