Letteratura scientifica selezionata sul tema "Palladium electrocatalyst"
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Articoli di riviste sul tema "Palladium electrocatalyst":
1
Kryukov, Yu I., V. I. Lukovtsev, Elena Mikhailovna Petrenko e I. S. Khozyainova. "Electrochemical activity of the cathodes with platinum or platinum-palladium electrocatalysts for alkaline water electrolysis". Electrochemical Energetics 12, n. 1 (2012): 36–38. http://dx.doi.org/10.18500/1608-4039-2012-12-1-36-38.
Abstract (sommario):
Electrochemical activity of cathodes with Pt or Pt-Pd-electrocatalysts was studied by voltammetry method under galvanostatic conditions. The dependence of the overvoltage of hydrogen evolution reaction on the logarithm of current density and on the test time of the cathode with Pt-Pd-electrocatalysts are defined. It is shown that the electrochemical activity of cathode with Pt-Pd-electrocatalyst is two times higher than with Pt-electrocatalyst at the hydrogen evolution reaction in 30% KOH solution at 90°C. As the temperature increases from 15 to 90° C the current density at 40 mV overvoltage at the cathode with Pt-Pd-electrocatalyst increases by 8 times. The test results with this cathode electrocatalyst in the laboratory electrolyzer at a current density of 400 mA/cm2 and 65° C temperature within 11 days of intermittent regime work confirm the overvoltage stability in time.
2
Ipadeola, Adewale K., e Kenneth I. Ozoemena. "Alkaline water-splitting reactions over Pd/Co-MOF-derived carbon obtained via microwave-assisted synthesis". RSC Advances 10, n. 29 (2020): 17359–68. http://dx.doi.org/10.1039/d0ra02307h.
3
Sofian, Muhammad, Fatima Nasim, Hassan Ali e Muhammad Arif Nadeem. "Pronounced effect of yttrium oxide on the activity of Pd/rGO electrocatalyst for formic acid oxidation reaction". RSC Advances 13, n. 21 (2023): 14306–16. http://dx.doi.org/10.1039/d3ra01929b.
4
Zheng, Jun Sheng, Xin Sheng Zhang, Sun Wen, Ping Li, Chun An Ma e Wei Kang Yuan. "A Novel Non-Metal Oxygen Reduction Electrocatalyst Based on Platelet Carbon Nanofiber". Advanced Materials Research 132 (agosto 2010): 264–70. http://dx.doi.org/10.4028/www.scientific.net/amr.132.264.
Abstract (sommario):
A novel non-metal electrocatalyst based on platelet carbon nanofiber (p-CNF) is prepared, and a palladium electrocatalyst supported on activated carbon (AC) is also synthesized. The physico-chemistry properties of the p-CNF and palladium catalyst on AC (Pd/AC) are investigated by high resolution transmission electron microscopy, N2 physisorption and Raman spectra analysis. From cyclic voltammetric studies, it is found that p-CNF is more active than Pd/AC in acidic media. The p-CNF shows a more positive oxygen reduction reaction (ORR) onset reduction potential and a higher oxygen reduction current density than Pd/AC. Moreover, the ORR is controlled by a surface reaction process when Pd/AC is used, while it becomes diffusion controlled when p-CNF is used.
5
Yazdan-Abad, Mehdi Zareie, Meissam Noroozifar, Ali Reza Modarresi-Alam e Hamideh Saravani. "Correction: Palladium aerogel as a high-performance electrocatalyst for ethanol electro-oxidation in alkaline media". Journal of Materials Chemistry A 5, n. 25 (2017): 13228. http://dx.doi.org/10.1039/c7ta90123b.
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Mansor, Muliani, Sharifah Najiha Timmiati, Wai Yin Wong, Azran Mohd Zainoodin, Kean Long Lim e Siti Kartom Kamarudin. "NiPd Supported on Mesostructured Silica Nanoparticle as Efficient Anode Electrocatalyst for Methanol Electrooxidation in Alkaline Media". Catalysts 10, n. 11 (25 ottobre 2020): 1235. http://dx.doi.org/10.3390/catal10111235.
Abstract (sommario):
The direct methanol fuel cell (DMFC) is a portable device and has the potential to produce 10 times higher energy density than lithium-ion rechargeable batteries. It is essential to build efficient methanol electrooxidation reaction electrocatalysts for DMFCs to achieve their practical application in future energy storage and conversion. A catalyst consisting of nickel–palladium supported onto mesostructured silica nanoparticles (NiPd–MSN) was synthesized by the wet impregnation method, while MSN was synthesized using the sol-gel method. MSN act as a catalyst support and has very good characteristics for practical support due to its large surface area (>1000 m2/g) and good chemical and mechanical stability. The microstructure and catalytic activity of the electrocatalysts were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), Brunauer–Emmet–Teller (BET) theory, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and chronoamperometry (CA). XRD showed that the NiPd–MSN electrocatalysts had a high crystallinity of PdO and NiO, while FESEM displayed that NiPd was dispersed homogeneously onto the high surface area of MSN. In alkaline media, the catalytic activity toward the methanol oxidation reaction (MOR) of NiPd–MSN demonstrated the highest, which was 657.03 mA mg−1 more than the other electrocatalysts. After 3600 s of CA analysis at −0.2 V (vs. Ag/AgCl), the MOR mass activity of NiPd–MSN in alkaline media was retained at a higher mass activity of 190.8 mA mg−1 while the other electrocatalyst was significantly lower than that. This electrocatalyst is a promising anode material toward MOR in alkaline media.
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Chen, Jingguang G. "(Invited) Electrocatalytic Conversion of CO2 to Syngas with Controlled CO/H2 Ratios". ECS Meeting Abstracts MA2023-01, n. 37 (28 agosto 2023): 2161. http://dx.doi.org/10.1149/ma2023-01372161mtgabs.
Abstract (sommario):
One of the main research challenges for electrocatalysis that produces carbon-containing products from CO2 is avoiding the competing hydrogen evolution reaction. Instead of totally eliminating hydrogen, our approach makes use of the readily available protons in aqueous electrolyte to co-produce CO and H2, making synthesis gas (syngas) with a tunable CO:H2 ratio. The resulting syngas can then be used as feedstock for existing thermocatalytic processes, such as Fischer–Tropsch and methanol synthesis reactions [1]. We will present our results in identifying palladium hydride (PdH), formed under electrocatalytic reaction conditions, as an effective electrocatalyst that enables the syngas production [2]. We will also report our efforts in reducing the loading of Pd by alloying Pd with inexpensive secondary metals, supporting Pd on transition metal carbides and nitrides, and utilizing single atom Pd catalysts. For each type of the catalysts, we monitor the phase transition from Pd to PdH under reaction conditions with in-situ synchrotron-based X-ray absorption and X-ray diffraction techniques. We also identify descriptors for syngas production on PdH, bimetallic PdH, and supported PdH catalysts by performing DFT calculations of the effect of PdH formation on the binding strength of reaction intermediates. The research methodology established here should be useful not only for continued optimization of Pd-based syngas-producing electrocatalysts, but also for enhancing activity while reducing the loading of precious metals for other electrocatalytic applications. Furthermore, we will discuss our recent results in utilizing a tandem scheme of electrocatalytic-thermocatalytic processes to convert CO2 to C3 oxygenates [3]. [1] B.M. Tackett, E. Gomez and J.G. Chen, “Net reduction of CO2 via its thermocatalytic and electrocatalytic transformation reactions in standard and hybrid processes”, Nature Catalysis, 2 (2019) 381. [2] B.M. Tackett, J.H. Lee and J.G. Chen, “Electrochemical Conversion of CO2 to Syngas with Palladium-Based Electrocatalysts”, Accounts of Chemical Research, 53 (2020) 1535. [3] A.N. Biswas, Z. Xie, R. Xia, S. Overa, F. Jiao and J.G. Chen, “Tandem Electrocatalytic-Thermocatalytic Reaction Scheme for CO2 Conversion to C3 Oxygenates”, ACS Energy Letters, 7 (2022) 2904
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Kabir, Sadia, Kenneth Lemire, Kateryna Artyushkova, Aaron Roy, Madeleine Odgaard, Debbie Schlueter, Alexandr Oshchepkov et al. "Platinum group metal-free NiMo hydrogen oxidation catalysts: high performance and durability in alkaline exchange membrane fuel cells". Journal of Materials Chemistry A 5, n. 46 (2017): 24433–43. http://dx.doi.org/10.1039/c7ta08718g.
Abstract (sommario):
A highly active NiMo electrocatalyst for HOR in alkaline media with power density at 0.5 V higher than 100 mW cm−2 (peak value of 120 mW cm−2), which is similar to palladium was synthesized and comprehensively studied.
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Eskandrani, Areej A., Shimaa M. Ali e Hibah M. Al-Otaibi. "Study of the Oxygen Evolution Reaction at Strontium Palladium Perovskite Electrocatalyst in Acidic Medium". International Journal of Molecular Sciences 21, n. 11 (27 maggio 2020): 3785. http://dx.doi.org/10.3390/ijms21113785.
Abstract (sommario):
The catalytic activity of Sr2PdO3, prepared through the sol-gel citrate-combustion method for the oxygen evolution reaction (OER) in a 0.1 M HClO4 solution, was investigated. The electrocatalytic activity of Sr2PdO3 toward OER was assessed via the anodic potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The glassy carbon modified Sr2PdO3 (GC/Sr2PdO3) electrode exhibited a higher electrocatalytic activity, by about 50 times, in comparison to the unmodified electrode. The order of the reaction was close to unity, which indicates that the adsorption of the hydroxyl groups is a fast step. The calculated activation energy was 21.6 kJ.mol−1, which can be considered a low value in evaluation with those of the reported OER electrocatalysts. The Sr2PdO3 perovskite portrayed a high catalyst stability without any probability of catalyst poisoning. These results encourage the use of Sr2PdO3 as a candidate electrocatalyst for water splitting reactions.
10
Vdovenkov, Frol, Eugenia Bedova e Oleg Kozaderov. "Phase Transformation during the Selective Dissolution of a Cu85Pd15 Alloy: Nucleation Kinetics and Contribution to Electrocatalytic Activity". Materials 16, n. 4 (15 febbraio 2023): 1606. http://dx.doi.org/10.3390/ma16041606.
Abstract (sommario):
This study determined the critical parameters for the morphological development of the electrode surface (the critical potential and the critical charge) during anodic selective dissolution of a Cu–Pd alloy with a volume concentration of 15 at.% palladium. When the critical values were exceeded, a phase transition occurred with the formation of palladium’s own phase. Chronoamperometry aided in the determination of the partial rates of copper ionization and phase transformation of palladium under overcritical selective dissolution conditions. The study determined that the formation of a new palladium phase is controlled by a surface diffusion of the ad-atom to the growing three-dimensional nucleus under instantaneous activation of the nucleation centres. We also identified the role of this process in the formation of the electrocatalytic activity of the anodically modified alloy during electro-oxidation of formic acid. This study demonstrated that HCOOH is only oxidated at a relatively high rate on the surface of the Cu85Pd15 alloy, which is subjected to selective dissolution under overcritical conditions. This can be explained by the fact that during selective dissolution of the alloy, a pure palladium phase is formed on its highly developed surface which has prominent catalytic activity towards the electro-oxidation of formic acid. The rate of electro-oxidation of HCOOH on the surface of the anodically modified alloy increased with the growth of the potential and the charge of selective dissolution, which can be used to obtain an electrode palladium electrocatalyst with a set level of electrocatalytic activity towards the anodic oxidation of formic acid.
Tesi sul tema "Palladium electrocatalyst":
1
Beliaeva, Kristina. "Captage et conversion électrochimique du CO2 dans des liquides ioniques et des solvants eutectiques profonds avec des catalyseurs à base de Pd". Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALI094.
Abstract (sommario):
Le captage et la réduction électrochimique du CO2 (CCU) est une solution pour décarboniser le secteur industriel. Cette technologie valorise la source de carbone peu chère en molécules carbonées à forte valeur ajoutée. Des nombreuses méthodes de valorisation du CO2 existent pour limiter la libération de ce gaz à effet de serre dans l’atmosphère. Pendant cette thèse, nous proposons le captage du CO2 complété par la conversion électrochimique en différentes molécules carbonées dans une cellule électrochimique. L’électroconversion de dioxyde de carbone est une méthode prometteuse grâce à des conditions réactionnelles douces en température et pression et la possibilité d’alimenter la cellule électrochimique avec de l’électricité produite par des énergies renouvelables. Ce procédé nécessite le développement de solvants de captage qui peuvent également jouer le rôle d’électrolyte pendant la réduction électrochimique du CO2. En même temps, le choix d’un matériau catalytique est indispensable pour la conversion sélective du CO2 en molécule(s) d’intérêt. Le choix du solvant de captage est souvent basé sur la capacité d’absorption du CO2, les stabilités chimique et électrochimique, les enjeux environnementaux et le coût. Les solvants eutectiques profonds (DESs) apparaissent comme des candidats très intéressants puisqu’ils répondent aux différents critères de sélection. Dans ce travail de thèse, nous focalisons sur le développement de ces nouveaux solvants émergents pour le captage et l’électroconversion du CO2 avec des catalyseurs à base de palladium. Le palladium est d’ailleurs connu pour être un électrocatalyseur effectif pour la transformation sélective du dioxyde de carbone en molécules type C1 tel que le monoxyde de carbone.Pendant cette thèse, nous avons synthétisé et testé électrochimiquement des nombreux DESs et des catalyseurs à base de palladium en vue de permettre la compréhension des mécanismes réactionnels de la réduction du CO2 en molécule de type C1. Les différentes techniques de caractérisation ont permis d’étudier les structures des matériaux catalytiques (morphologie et tailles des particules) et des solvants eutectiques profonds, d’analyser les produits et les intermédiaires réactionnels ainsi que de comprendre les verrous du système utilisé. Dans sa globalité, le projet a permis de faire un pas vers la séquestration et la valorisation du dioxyde de carbone par la méthode électrochimique pour décarboniser le secteur industriel et empêcher ainsi le dérèglement climatiqueCarbon dioxide capture and utilization (CCU) is a way to decarbonize industrial sector. This technology provides a valorization of cheap carbon feedstock by its transformation to carbonaceous value-added chemicals. Multiple CO2 capture and utilization techniques exist to prevent the release of the greenhouse gas to the atmosphere. Here, we propose an integrated process of CO2 capture sequenced by electroconversion to C-based products in electrochemical cell. Electrochemical CO2 conversion is a promising method due to mild reaction conditions and possibility to power the reaction with electricity produced by renewable energy sources. This process necessitates the development of solvents capable to capture CO2 and to play a role of electrolyte during electrochemical reduction reaction. At the same time, efficient catalytic materials are vital for selective CO2 conversion to targeted product(s). The choice of capture solvent is usually based on CO2 capture ability, chemical and electrochemical stabilities, environmental issue and cost. Economically affordable deep eutectic solvent (DES) electrolytes seem to be promising candidates for CO2 capture and electroreduction because of good thermal and electrochemical stabilities, competitive CO2 uptake and large electrochemical windows. In this work, we focused on the development of novel deep eutectic solvent electrolytes for CO2 electroreduction with Pd-based electrocatalysts. Palladium proved its efficiency for selective conversion of carbon dioxide to C1 molecules such as carbon monoxide.During the thesis, we synthesized and electrochemically tested multiple DESs and Pd-based electrocatalysts with different morphologies and particle sizes to get more insights into reaction mechanism of CO2 electroreduction to C1 molecules. The implementation of different characterization techniques helped to study catalytic materials and DESs structures, to analyze gaseous and liquid reaction intermediates and products, and to understand main challenges of the studied system. Overall, this study is a one step forward the application of CO2ER (carbon dioxide electrochemical reduction) for valorisation of carbon dioxide and climate change mitigation
2
Straistari, Tatiana. "Synthesis and study of coordination compounds of cobalt, copper, palladium and nickel with polydentate ligands containing sulfur". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4352.
Abstract (sommario):
Ce travail porte sur la synthèse, la caractérisation et l’évaluation en catalyse de réduction des protons en dihydrogène, de nouveaux complexes de Ni(II), Co(III), Cu(II) et Pd(II) basés sur des ligands de type thiosemicarbazone. La nature de l’espèce catalytique active a été étudiée par voltampérométrie cyclique et des propositions de mécanisme ont été formulés sur la base de calcul quantique de type DFT.Le premier chapitre introduit le contexte scientifique. Le second chapitre concerne la synthèse et la caractérisation des ligands de type N2S2 et des complexes mononucléaires associés de Ni, Cu et Pd. Le troisième chapitre présente la synthèse et la caractérisation de complexes binucléaires de Co et trinucléaire de Ni.Les études électrochimiques de ces complexes dans le DMF en présence d’une source de protons, nous a permis d’évaluer leur efficacité catalytique. Nos résultats montrent que les complexes du Cu et du Pd présentent une vague irréversible spécifique pour la réduction des protons, mais une décomposition est observée durant l’électrolyse. Par contre, les complexes de Ni et de Co ont montré une stabilité électrochimique ainsi que de bonnes performances catalytiques. En particulier, le nouveau complexe mononucléaire de Ni présente des propriétés catalytiques remarquables qui le classent parmi les meilleurs catalyseurs de la réduction des protons décrits dans la littérature. L’ensemble de ce travail fourni une description complète du comportement électrochimique des ligands de type N2S2 complexés à des métaux de transition. Il permet d’envisager des développements futurs dans l’amélioration des propriétés catalytiques de ces complexesThis work focuses on the synthesis, the characterization and the catalytic evaluation in the reduction of protons into dihydrogen, of new complexes of Ni(II), Co(III), Cu(II) and Pd(II) based ligands Type thiosemicarbazone. The catalytically active species during the process of the proton reduction was studied by cyclic voltammetry and mechanisms were formulated on the basis quantum chemical calculation.The first chapter introduces the scientific context, the goals and the main objectives of this work. The second chapter concerns the synthesis and the characterization of the N2S2 ligands and their associated mononuclear complexes, Ni, Cu and Pd. The third chapter presents the synthesis and the characterization of binuclear Co and trinuclear Ni based on N2S2 ligand.Electrochemical studies of these complexes in DMF in the presence of a proton source (trifluoroacetic acid), allowed us to evaluate their catalytic efficiency. Our results show that Cu and Pd complexes have a specific irreversible wave for the reduction of protons, but decomposition is observed during electrolysis, which makes these uninteresting complexes for the reduction of protons.On the contrary, Ni and Co complexes showed an electrochemical stability and good catalytic performances. In particular, the new mononuclear Ni complex exhibits remarkable catalytic properties that rank it among the best catalysts for the reduction of protons reported in the literature. All this work provided a complete description of the electrochemical behavior of N2S2 thiosemicarbazone ligands complexed to transition metals. It allows considering future developments in improving the catalytic properties of these complexes
3
Tang, Yongan. "SYNTHESIS AND ELECTROCATALYSIS OF METAL NANOMATERIALS". Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1402313477.
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Klaas, Lutho Attwell. "Synthesis and characterization of binary Palladium based electrocatalysts towards alcohol oxidation for fuel cell application". University of the Western Cape, 2018. http://hdl.handle.net/11394/6448.
Abstract (sommario):
Magister Scientiae - MSc (Chemistry)The anode catalyst is one of the important parts of the direct alcohol fuel cell (DAFC); it is responsible for the alcohol oxidation reaction (AOR) takes place at the anode side. Pd has been reported to have good alcohol oxidation reactions and good stability in alkaline solution. Better stability and activity has been reported for Pd alloyed catalysts when compared to Pd. Choosing a suitable alcohol also has an effect on the activity and stability of the catalyst. This study investigates the best catalyst with better AOR and the best stability and also looks at the better alcohol to use between glycerol and ethanol for the five in-house catalysts (20% Pd, PdNi, PdNiO, PdMn3O4 and PdMn3O4NiO on multi walled carbon nanotubes) using cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectrometry (EIS) and chronoamperometry. HR-TEM and XRD techniques were used to determine the particle size and average particle size, respectively while EDS used to determine elemental composition and ICP was used to determine catalyst loading. It was observed from LSV that PdNiO was the most active catalyst for both ethanol and glycerol oxidation, and it was the most stable in ethanol while PdMn3O4 proved to be the most stable catalyst in glycerol observed using chronoamperometry. The best alcohol in this study was reported to be glycerol having given the highest current densities for all the inhouse catalysts compared to ethanol observed using LSV. From XRD and HR-TEM studies, particle sizes were in the range of 0.97 and 2.69 nm for XRD 3.44 and 7.20 nm for HR-TEM with a little agglomeration for PdMn3O4 and PdMn3O4NiO.
5
Sahin, Nihat Ege. "Réduction électrochimique du dioxyde de carbone sur des électrocatalyseurs à base de cuivre". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2313/document.
Abstract (sommario):
Le réchauffement climatique est dû principalement à l'émission anthropique du dioxyde de carbone (CO2) dans l'atmosphère. Une réduction électrocatalytique et sélective de cette molécule a été proposée au cours de ce projet comme une solution prometteuse pour synthétiser des produits à valeur ajoutée. Une telle réaction requiert l'utilisation de matériaux efficaces et bas coût. Pour ce faire, les travaux de cette thèse ont porté sur la préparation de catalyseurs à base de cuivre dispersés sur différents substrats carbonés tels que le Vulcan XC-72R, les carbones mésoporeux CMK-3 et FDU-15, et des tanins à base d'IS2M pour réduire le CO2 en milieu aqueux. Les matériaux d'électrode ont été préparés à l'aide de la méthode polyol assistée par micro-ondes. Leurs caractérisations physiques et l'analyse élémentaire confirment des compositions atomiques et des taux de charge métallique proches de celles théoriquement envisagées. L'acide formique et le monoxyde de carbone sont les deux produits carbonés issus de la réduction du CO2 (2 bar) réalisée par chronoampérométrie en milieu NaHCO3. La détection et l'identification des produits de réaction ont été effectuées par des méthodes chromatographiques (µ-GC et HPLC), spectrométrique (DEMS) et spectroscopique (RMN). Une sélectivité de la réaction vis-à-vis de HCOOH (62 %) a été obtenue sur une cathode de Cu50Pd50/C. Cette conversion sélective du CO2 en HCOOH s'explique par une conjugaison d'effets électroniques et géométriques dans la structure de surface du catalyseur bimétallique et aussi celui de la texture du substrat carbonéThe anthropogenic emissions of carbon dioxide (CO2) are the major cause of global warming. The selective CO2 reduction reaction (CO2RR) of has been proposed as a promising, convenient and efficient method for sustainable energy conversion systems. The reduction of CO2 to energetically valuable products requires the use of an appropriate electrode material. This study focuses on the preparation of Cu-based electrocatalysts supported on different types of carbon materials such as Vulcan XC-72R, mesoporous carbon CMK-3, mesoporous carbon FDU-15 and tannin based mesoporous carbon IS2M for the CO2RR under mild conditions. Besides, Vulcan XC-72R carbon supported bimetallic copper/palladium alloy materials were prepared for increasing the Faradaic yield. These copper-based catalysts were electrochemically characterized and preparative electrolyses set at constant potential were carried out in order to investigate the reduction products distribution and Faradaic yields as a function of the applied potential and catalyst loading. Chemicals such as HCOOH, CO and H2 issued from the CO2RR, were determined with in-situ and ex-situ complementary (electro)analytical and spectroscopic techniques. The significant difference in the product distribution is probably due to the ensemble (geometry and ligand) effects in the bimetallic CuPd materials, and textural structure of the supporting substrates. Selective CO2 to-HCOOH conversion has been successfully undertaken on Cu50Pd50/C with 62 % Faradaic efficiency
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Parent, Loic. "Synthèse et caractérisation de nanoparticules métalliques hybrides à base de polyoxométallates : applications à l'électro-catalyse". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLV010/document.
Abstract (sommario):
Les polyoxométallates (POMs) sont aujourd'hui reconnus pour leurs diverses architectures et applications. Nous nous en sommes ici servis afin de synthétiser des nanoparticules de palladium puisque le POM va jouer à la fois le rôle de réducteur du cation métallique mais aussi de surfactant des nanoparticules.Après avoir fait, dans un premier temps, l'étude électrochimique d'une série de POMs issus de la même famille, deux d'entre-eux ont été utilisés pour la synthèse de nanoparticules de palladium. D'une taille moyenne comprise entre 15 et 20 nm, ces nanoparticules ont été entièrement caractérisées et se sont avérées stables un intervalle de temps d'au moins un mois.Enfin, divers matériaux hybrides à base de palladium et/ou de cuivre ont été caractérisés par électrochimie à l'état solide et leur pouvoir catalytique vis-à-vis de la réduction des ions nitrate et de l'oxygène a été évaluéPolyoxometalates (POMs) are known for their high diversification in terms of architectures and applications. POMs are used in this work for the synthesis of palladium nanoparticles since they act both as a reducer of metallic cation and as surfactant of nanoparticles.At first, we studied the electrochemical properties of several POMs belonging in the same family, then among this family, we chose to use two particular POMs to synthesize palladium nanoparticles. From an average size between 15 and 20 nm, these nanoparticles have been fully characterized and are stable over a month.Finally, various hybrid materials based on palladium and/or copper have been characterized by electrochemistry in solid state and their catalytic capacity towards the reduction of nitrate ions and dioxygene has been assessed
7
Straistari, Tatiana. "Synthesis and study of coordination compounds of cobalt, copper, palladium and nickel with polydentate ligands containing sulfur". Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4352.
Abstract (sommario):
Ce travail porte sur la synthèse, la caractérisation et l’évaluation en catalyse de réduction des protons en dihydrogène, de nouveaux complexes de Ni(II), Co(III), Cu(II) et Pd(II) basés sur des ligands de type thiosemicarbazone. La nature de l’espèce catalytique active a été étudiée par voltampérométrie cyclique et des propositions de mécanisme ont été formulés sur la base de calcul quantique de type DFT.Le premier chapitre introduit le contexte scientifique. Le second chapitre concerne la synthèse et la caractérisation des ligands de type N2S2 et des complexes mononucléaires associés de Ni, Cu et Pd. Le troisième chapitre présente la synthèse et la caractérisation de complexes binucléaires de Co et trinucléaire de Ni.Les études électrochimiques de ces complexes dans le DMF en présence d’une source de protons, nous a permis d’évaluer leur efficacité catalytique. Nos résultats montrent que les complexes du Cu et du Pd présentent une vague irréversible spécifique pour la réduction des protons, mais une décomposition est observée durant l’électrolyse. Par contre, les complexes de Ni et de Co ont montré une stabilité électrochimique ainsi que de bonnes performances catalytiques. En particulier, le nouveau complexe mononucléaire de Ni présente des propriétés catalytiques remarquables qui le classent parmi les meilleurs catalyseurs de la réduction des protons décrits dans la littérature. L’ensemble de ce travail fourni une description complète du comportement électrochimique des ligands de type N2S2 complexés à des métaux de transition. Il permet d’envisager des développements futurs dans l’amélioration des propriétés catalytiques de ces complexesThis work focuses on the synthesis, the characterization and the catalytic evaluation in the reduction of protons into dihydrogen, of new complexes of Ni(II), Co(III), Cu(II) and Pd(II) based ligands Type thiosemicarbazone. The catalytically active species during the process of the proton reduction was studied by cyclic voltammetry and mechanisms were formulated on the basis quantum chemical calculation.The first chapter introduces the scientific context, the goals and the main objectives of this work. The second chapter concerns the synthesis and the characterization of the N2S2 ligands and their associated mononuclear complexes, Ni, Cu and Pd. The third chapter presents the synthesis and the characterization of binuclear Co and trinuclear Ni based on N2S2 ligand.Electrochemical studies of these complexes in DMF in the presence of a proton source (trifluoroacetic acid), allowed us to evaluate their catalytic efficiency. Our results show that Cu and Pd complexes have a specific irreversible wave for the reduction of protons, but decomposition is observed during electrolysis, which makes these uninteresting complexes for the reduction of protons.On the contrary, Ni and Co complexes showed an electrochemical stability and good catalytic performances. In particular, the new mononuclear Ni complex exhibits remarkable catalytic properties that rank it among the best catalysts for the reduction of protons reported in the literature. All this work provided a complete description of the electrochemical behavior of N2S2 thiosemicarbazone ligands complexed to transition metals. It allows considering future developments in improving the catalytic properties of these complexes
8
Chen, Yan Xin. "Nanostructured TiO2 Based Materials for electrocatalysis and Photoelectrocatalysis". Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8574.
Abstract (sommario):
2011/2012Fossil energy sources are non-renewable being an irreplaceable endowment produced from millennia of biological and geological processes, which means that on the human time-scale they cannot be naturally regenerated and are only available in a finite amount on earth. Scientific and technological data concerning renewable fuels are exponentially growing and in parallel the governments are more and more attracted by these more sustainable energy sources. Overall, solar energy is the most abundant and easily available renewable resource which, however, has its own problems such as neither constantly available nor distributed equally over the surface of the globe. Hydrogen and various bio-fuels, such as bio-ethanol, biodiesel or biogas, have the potentiality to store the solar energy, playing a crucial role in the development of future renewable energy strategies. Nevertheless, as a general comment, it is very difficult and expensive to harness enough power from them to match the effectiveness of non-renewable resources. Thus, it is a big challenge to develop new and high efficient approach to improve the efficiency in production and use of these renewable resources. Nanotechnology is a key area that can help solving this issue. In fact, by using the tools offered by nanotechnology, it is possible to obtain tailored nanostructured catalytic materials that show remarkably better performance than that currently achievable even with state-of- the-art materials. The fields of catalysis, electrocatalysis, photocatalysis and photoelectron- catalysis are all examples of where nanotechnology is deeply impacting on current science, and in particular in energy related applications. The main focus of this PhD thesis is on nanotechnology applied to material science to enhance the performances of various on two important energy-related processes: namely the Fuel Cells (especially the Direct Alcohol Fuel Cell - DAFC) and the hydrogen production process. The H2 production processes include the electrochemical H2 production approach (the water electrolysis technique) and the photocatalytical H2 production approach (the photocatalytic decomposition of water into H2 technique). In the both the energy conversion processes, TiO2 nanotube arrays (TNTA) architectures were used as substrates and the Palladium (Pd) nanoparticles (NPs) were used as supported nanocatalysts. Therefore the most important results in this thesis are the design, realization, functional testing and characterization of supported Pd nanocatalysts on various TiO2 substrates with tailored and well-defined structures, in addition their use for energy-related applications, which are organized as follows: In the Chapter 1, the general principles of the fuel cells technique; the electrolysis technique; the TNTA substrate architecture and the principles of photocatalytic processes for H2 production are outlined or described in details. In addition, the development status and the preparation strategies of catalysts for the alcohol electrochemical oxidation are introduced in this chapter. In the chapter 2, an overview of the main characterization techniques is reported, all of which have been used in this thesis, in order to study the reactivity and the morphological and chemical properties of the samples. The aim of the present chapter is not that of providing exhaustive information about all the techniques. Rather, it is expected to furnish to the reader the main elements to better appreciate the results obtained and described in the following chapters of this thesis. Since the catalytic performance of the nanocatalysts can be finely turned by their shape, which determines surface atomic arrangement and coordination. In the chapter 3,we report a novel method of metal NPs modification, denoted as Electrochemical Milling and Faceting (ECMF), by which large supported Pd NPs (35 nm) of low-index facets supported on TNTA substrate can be milled into many small NPs (7 nm) with some HIF or high density of step atoms. By this approach, the catalytic activity of supported Pd NPs was enhanced by an order of magnitude to the ethanol electrooxidation, and was even 3 times higher than the highest value reported so far. This new approach to the synthesis of HIF-Pd NPs allows one to control metal loading, particle size and surface structure, independently from each other. Furthermore, in a practical catalytic system, such as the DAFC; the electrolysis system and the photocatalytical H2 production system, the electrochemical activity of the supported catalysts is not the only one parameter which needs to be concerned about, the other parameters for the whole test system’s establishment such as the selection and preparation of the substrate material also need to the carefully optimize. In the chapter 4, a new type of Ti network substrate with the TNTA on top was prepared and introduced into the DAFC test system and also used in the electrolysis and photocatalytical H2 production process. This kind of substrate solved the typical problems of the DAFC such as the fuel solution diffusion limitation and the stability of the as supported catalysts drop during the large current density discharge. It was also proved to be a good choice as the substrate for the Photocatalytic decomposition of alkaline ethanol aqueous into H2, which showed good performances of the H2 photochatalytic evolution. Chapter 5 is the conclusion of my PhD thesis. The results clearly demonstrate the novelty and the advantage of the present approach for the obtainment of active and stable electrochemical catalysts for the DAFC and the electrolysis system, and also represent an important step forward in the exploration of new active nanosystems for the conversion of solar light into storable chemical energy. All the findings greatly contributed to the development of catalytic materials for energy-related applications.
XXV Ciclo
1983
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Madduma-Liyanage, Kumudu C. "Reactions of Pt(IV) and Pd(IV) Complexes with Multi-Electron Substrates". University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416570506.
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BRANDALISE, MICHELE. "Preparação e caracterização de eletrocatalisadores a base de paládio para oxidação eletroquímica de álcoois em meio alcalino". reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10137.
Abstract (sommario):
Made available in DSpace on 2014-10-09T12:35:11Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:01:22Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Capitoli di libri sul tema "Palladium electrocatalyst":
1
Adzic, Radoslav, e Nebojsa Marinkovic. "Palladium Monolayer Electrocatalysts". In Platinum Monolayer Electrocatalysts, 157–60. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-49566-4_10.
2
Shao, Minhua. "Palladium-Based Electrocatalysts for Oxygen Reduction Reaction". In Lecture Notes in Energy, 513–31. London: Springer London, 2013. http://dx.doi.org/10.1007/978-1-4471-4911-8_17.
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Bianchini, C. "4 Palladium-Based Electrocatalysts for Alcohol Oxidation in Direct Alcohol Fuel Cells". In Modern Aspects of Electrochemistry, 203–53. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-5580-7_4.
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Yoo, Sung Jong, e Yung-Eun Sung. "Design of Palladium-Based Alloy Electrocatalysts for Hydrogen Oxidation Reaction in Fuel Cells". In Fuel Cell Science, 111–46. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2010. http://dx.doi.org/10.1002/9780470630693.ch3.
Atti di convegni sul tema "Palladium electrocatalyst":
1
Chen, Chun-Mao, Ming-Long Yeh, Chia-Yen Lee, Ya-Ting Chuang e Che-Hsin Lin. "A hydrogen evolution reaction determination system integrated high electrocatalyst palladium nano-electrode ensemble". In 2009 IEEE Sensors. IEEE, 2009. http://dx.doi.org/10.1109/icsens.2009.5398184.
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De Oliveira Vigier, Karine, Christophe Coutanceau e Steve Baranton. "Electro-oxidation of glycerol and diglycerol in the presence of Pt or Pd-based electrocatalyst follows by the reductive amination of the products obtained". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/olba8004.
Abstract (sommario):
The selective electro-oxidation of bio-based organic molecules such as glycerol, polyglycerols, saccharides and furanic compounds has received particular attention in recent years, due to the high value-added compounds that result and their numerous industrial applications. Electrochemical methods are therefore well suited for the controlled oxidation of small organic molecules in aqueous media. Glycerol valorization through partial oxidation is a good way of obtaining many different molecules with high added value such as glyceric acid, tartronic acid, dihydroxyacetone, glyceraldehyde etc., that can find various applications in different domains such as organic chemistry, medical, and cosmetic industries. Here we have studied the electro-oxidation of glycerol in the presence of Pt or Pd-based catalysts. The development of mono- and bimetallic catalysts based on platinum on the one hand and palladium on the other hand for the electro-oxidation of glycerol is a very important goal to direct the reaction pathways to desired products.            Bimetallic catalysts synthesized by the water-in-oil microemulsion method were characterized by physicochemical (TEM, XRD, ATG, SAA and ICP-OES) and electrochemical (active surface and surface composition study) methods in order to obtain a correlation between surface structure and electrochemical response. The reactivity of glycerol and diglycerol in alkaline medium was evaluated to determine the catalyst offering the best conversion. A selectivity study of these catalysts was performed by in situ infrared spectroscopy to determine the reaction intermediates. The distribution of reaction products was determined by HPLC analysis and 1H and 13C NMR analyses.
           Reductive amination reactions with ammonia on the one hand and n-butylamine on the other hand on products identified as being of interest (glyceraldehyde/dihydroxyacetone) were carried out in the presence of hydrogen and catalyzed by palladium-based nanoparticles dispersed on carbon.
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Wheeldon, I. R., J. C. Amphlett, M. Fowler, M. Hooper, R. F. Mann, B. A. Peppley e C. P. Thurgood. "Simulation of a 25 kW Steam-Methanol Fuel Processor/PEM Fuel Cell System". In ASME 2003 1st International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2003. http://dx.doi.org/10.1115/fuelcell2003-1738.
Abstract (sommario):
The transition to a hydrogen economy will require an intermediate energy carrier until a sufficient hydrogen infrastructure can be implemented. A likely near-term candidate is the on-board or on-site production of hydrogen from steam-methanol reforming. The low tolerance of PEM fuel cell anode electrocatalyst, to the carbon monoxide produced during reforming, necessitates a hydrogen purification or carbon monoxide clean-up sub-system. Considerable advantages can be gained from the use of a steam-methanol reformer with a palladium-silver alloy membrane, hydrogen purification unit. In the present work we have examined such a system. A simulation comprised of a Polymer Electrolyte Membrane Fuel Cell electrochemical model, a membrane permeation model and a commercially available thermodynamics calculation package was constructed. The case investigated in this work is of a 25 kW nominal DC power generating system. A maximum efficiency of 40% was achieved at reformer and membrane unit conditions of 200°C and 300 psia with 97% conversion of the inlet methanol. The effects of variation in temperature and pressure where also investigated. It was found that the reformer and membrane unit pressure had the most significant effect on overall system efficiency. The system efficiency increases with pressure reaching a maximum at the upper limit of the operating region, 300 psia.