Rozprawy doktorskie na temat „Palladium electrocatalyst”
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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.
Pełny tekst źródłaCarbon 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
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.
Pełny tekst źródłaThis 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
Tang, Yongan. "SYNTHESIS AND ELECTROCATALYSIS OF METAL NANOMATERIALS". Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1402313477.
Pełny tekst źródłaKlaas, 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.
Pełny tekst źródłaThe 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.
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.
Pełny tekst źródłaThe 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
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.
Pełny tekst źródłaPolyoxometalates (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
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.
Pełny tekst źródłaThis 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
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.
Pełny tekst źródłaFossil 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
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.
Pełny tekst źródłaBRANDALISE, 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.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Pizzutilo, Enrico [Verfasser], Gerhard [Gutachter] Dehm i Karl J. J. [Gutachter] Mayrhofer. "Towards on-site production of hydrogen peroxide with gold-palladium catalysts in electrocatalysis and heterogeneous catalysis / Enrico Pizzutilo ; Gutachter: Gerhard Dehm, Karl J. J. Mayrhofer". Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1144614716/34.
Pełny tekst źródłaRafaïdeen, Thibault. "Étude de l'activation électro-catalytique de composés issus de la biomasse". Thesis, Poitiers, 2019. http://www.theses.fr/2019POIT2276.
Pełny tekst źródłaLignocellulosic biomass is a renewable resource and an almost inexhaustible reservoir of carbon and hydrogen for many energy applications and / or fine chemicals. Lignocellulosic biomass is mainly composed of biopolymers (cellulose, hemicellulose and lignin), two of which (cellulose and hemicellulose) are composed of sugars (glucose, xylose, mannose, galactose, etc.). The oxidation of these sugars, particularly glucose and, allows the production of high added value platform molecules such as gluconic, glucaric and xylonic acids, etc. With a suitable catalyst, it is possible to orient in an electrochemical reactor the oxidation of these sugars to the desired molecules with the co-production of dihydrogen. Mono- and bi-metallic palladium and gold nanoparticles supported on carbon (PdxAu10-x / C, with x = 0, 1, 3, 5, 7, 9, 10) were synthesized by the colloidal method called "Water-in-oil". These catalysts have been characterized by physico-chemical and electrochemical methods in order to know the relationships between composition, structure and electrochemical response. The reactivity of glucose and xylose in alkaline medium was evaluated to determine the catalyst with the best conversion. A study of the selectivity of these catalysts was carried out by infrared spectroscopy in situ. The best catalyst in terms of activity and selectivity was used at the anode of a 25 cm² electrolysis cell and electrolyses of alkaline solutions of glucose or xylose were carried out at different voltages and concentrations of sugars in order to evaluate the distribution of reaction products by HPLC and 1H NMR at high conversion rate of reagents. After studying the influence of the PdxAu10-x / C catalyst composition, the influence of the surface structure was studied with palladium nanoparticles synthesized by a colloidal method making possible to obtain unsupported nanospheres, nanocubes and nanooctahedrons. These nanoparticles have different major surface orientations associated with their shape. In addition, the study of the surface composition in relation to the surface orientation was carried out by depositing gold adatoms on these particle surface by immersing them in solutions of tetrachloroauric acid at different concentrations. The characterizations of particles by TEM and electrochemically means, allowed the correlation of the electrochemical responses and the structure / composition of surfaces. The activity for glucose and xylose oxidation reaction was evaluated on these different particles
Takky, Driss. "Effet de la structure moléculaire en electrocatalyse : étude mécanistique de l'oxydation des isomères du butanol en milieu aqueux sur diverses électrodes de metaux nobles". Poitiers, 1987. http://www.theses.fr/1987POIT2008.
Pełny tekst źródłaGallo, Irã Borges Coutinho. "Surface structure and electronic properties of carbon supported PdAu nanoparticles and their catalytic behavior toward the oxygen reduction reaction /". Araraquara, 2018. http://hdl.handle.net/11449/153370.
Pełny tekst źródłaBanca: Rodrigo Fernando Costa Marques
Banca: Leandro Martins
Banca: Elisabete Inacio Santiago
Banca: Joelma Perez
Abstract: Carbon supported PdAu nanoparticles with different Au contents (20-50% in atoms) were synthesized using a procedure carried out in a liquid two-phase system. As-prepared materials presented similar average particle diameter (~3nm) with narrow distribution over the carbon support, as shown by Transmission Electronic Microscopy (TEM). The combined data from X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) suggest that nanoparticles had Pd-enriched surfaces and Au-rich interiors. Cyclic Voltammetry (CVs) studies in H2SO4 further reinforced these findings, confirming that the nanoparticle surfaces were enriched with Pd. Moreover, XPS results show that increasing the Au content of PdAu alloys leads to varying amounts of surface-like and bulk-like Pd oxide, with a significant increase of metallic Pd. This result is consistent with data of X-ray Absorption Spectroscopy (XAS) around Pd L3 edge, which revealed that Au promotes an increase in the electronic occupancy of the Pd 4d band. Therefore, this whole set of characterizations suggests that the presence of Au in PdAu nanoalloys decreases the Pd affinity for oxygen, giving Pd a more noble-like character. In addition, the influence of ligand and ensemble effects on electrochemical surface processes, such as oxide formation/reduction, CO oxidation and hydrogen adsorption were also investigated. This was also a necessary step in order to determine the best technique to measure the Electrochemical Active Area (EAA) of... (Complete abstract click electronic access below)
Resumo: Nanopartículas de PdAu suportadas em carbono com diferentes frações de Au (20-50% em átomos) foram sintetizadas em um sistema líquido de duas fases. As nanopartículas preparadas apresentaram diâmetro médio próximo a 3 nm, com uma distribuição homogênea sobre o suporte de carbono, o que foi demonstrado por microscopia eletrônica de transmissão (TEM). O conjunto dos dados coletados por difração de raios X (XRD) e por espetroscopia de fotoelétrons excitados por raios X (XPS) demonstrou que o interior das nanopartículas é enriquecido por Au, enquanto a superfície é mais rica em Pd. A análise por XPS também demonstrou que o aumento da fração de Au nas ligas de PdAu leva a uma variação na fração de diferentes espécies de óxidos de Pd e um aumento na quantidade total de Pd metálico. Este resultado é consistente com aquele obtido por espectroscopia de absorção de raios-X (XAS), realizada na borda L3 do Pd, a qual revelou que o Au promove um preenchimento eletrônico na banda 4d do Pd. Ou seja, a presença do Au parece diminuir a afinidade do Pd pelo oxigênio. Ademais, foram estudados a influência de efeitos eletrônicos e do arranjo superficial de átomos sobre os processos eletroquímicos de formação/redução de óxidos, oxidação de CO adsorvido e adsorção de hidrogênio. Estes estudos também permitiram a determinação da área eletroquímica ativa de Pd. Por meio de todas estas caracterizações foi possível traçar correlações entre a composição no cerne das nanopartículas de PdAu e suas propri... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
Holade, Yaovi. "Transformation électrocatalytique de sucres couplée à la réduction enzymatique de l'oxygène moléculaire pour la production d'énergie". Thesis, Poitiers, 2015. http://www.theses.fr/2015POIT2262/document.
Pełny tekst źródłaThe development of energy converters to power implanted micro-electronic devices has become a cornerstone item. The whole target which has governed this research was the design of advanced nanostructures metals used as electrocatalysts for converting chemical energy into electrical one. These nanomaterials were obtained by the synthesis method: Bromide Anion Exchange (BAE) that has been carefully revisited and optimized, using a weak reducing agent (AA) and strong one (NaBH4). It allowed to prepare efficiently various plurimetallic nanomaterials composed of gold, platinum and palladium (yield ≥ 90%). A thermal pretreatment of commercial carbon supports of nanoparticles has highly boosted their specific and active surface areas with a gain of 48 and 120%. Based on in situ and ex-situ (electro)analytical methods, the intermediates and final reaction products of the fuel oxidation were identified. Glucose electrooxidation occurs without C-C bond cleavage and gives predominantly gluconate with a selectivity ≥ 88 %. Results from the hybrid biofuel cell tests (with an enzyme as cathode catalyst) indicate that Au/C-AA and Au60Pt40/C-NaBH4 are the best abiotic anodes (Pmax = 125 µW cm-2 at 0.4 V cell voltage). A fuel cell without separating membrane and enzyme has been successfully constructed and used to activate a pacemaker and an information transmission system based on "wireless" mode. These last experiments, reported for the first time as using nanomaterials in membrane-less configuration, open a new approach in the design of advanced energy converters to power medical implants or remote systems for detection and electronic monitoring
BONIFACIO, RAFAEL N. "Estudo e desenvolvimento de conjuntos membrana-eletrodos (MEA) para célula a combustível de eletrólito polimérico condutor de prótons (PEMFC) com eletrocatalisadores à base de paládio". reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10597.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Maumau, Rebecca. "Synthesis of binary and ternary Pd-based Nanocatalysts for alcohol oxidation in alkaline media for fuel cell application". University of the Western Cape, 2020. http://hdl.handle.net/11394/7731.
Pełny tekst źródłaThis study explores the use of UV-assisted reduction method to synthesise the catalysts, aiming at reducing synthesis time. The Pd and Au catalyst loading is kept at 5 wt% in order to reduce the cost associated with high loading (20 wt%) of platinum group metals. The synthesised catalysts have SnO2 incorporated in them for two purposes, one being to activate the chemical reaction by absorbing UV-light and the second one is to serve as a promoter for binary and ternary catalysts. All the synthesised electrocatalysts in this study were denoted as Au/10wt%SnO2-C, Au/15wt%SnO2-C, Au/20wt%SnO2-C, Au/40wt%SnO2-C, Au/60wt%SnO2-C, Pd/10wt%SnO2-C, Pd/15wt%SnO2-C, Pd/20wt%SnO2-C, Pd/40wt%SnO2-C, Pd/60wt%SnO2-C and PdAu/10wt%SnO2-C respectively. The UV-assisted reduction method was proved to be effective with the obtained results from TEM, SEM, XRD and electrochemical studies. TEM micrographs revealed nanoparticles of Pd, Au and SnO2 which were proved by the measured d-spacing values corresponding to the element’s structures. The measured average particle size ranged from 3.05 to 14.97 nm for the electrocatalysts. The XRD profiles confirmed the face centred cubic of Pd, Au and tetragonal structures of SnO2. These electrocatalysts showed varied activity towards the oxidation of alcohols namely, methanol, ethanol, ethylene glycol and glycerol in alkaline electrolyte The cyclic voltammetry results showed improved performance towards the oxidation of glycerol on Au-based electrocatalysts, highest current density of 22.08 mA cm-2 than on Pd-based electrocatalysts. Pd-based electrocatalysts were more active towards the oxidation of ethanol than Au-based electrocatalysts with the highest current density of 19.96 mA cm-2. The co-reduced PdAu on 10wt%SnO2-C electrocatalysts showed the lowest current density of 6.88 mA cm-2 for ethanol oxidation when compared to Pd/10wt%SnO2-C and Au/10wt%SnO2-C. Linear sweep voltammograms showed more negative onset potentials on Pd-based electrocatalysts than Au-based electrocatalysts. The more negative onset potential obtained on Pd-based electrocatalysts was observed for ethanol oxidation. These results correspond to the trend observed in literature for ethanol oxidation being more favoured on Pd-based electrocatalysts whereas the polyalcohol oxidation is more favoured on Au-based electrocatalysts. The best performing and most stable electrocatalyst among the Au-based electrocatalysts is Au/10wt%SnO2-C and Pd/10wt%SnO2-C for the Pd-based electrocatalysts.
Lafforgue, Clémence. "Activité et mécanismes de dégradation d'électrocatalyseurs anodiques pour la pile directe à borohydrures". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI055/document.
Pełny tekst źródłaThe direct borohydride fuel cell (DBFC), a subclass of alkaline fuel cells, benefits from the advantages of its fuel, sodium borohydride (NaBH4), which exhibits very interesting thermodynamic and energetic characteristics. However, the NaBH4 electrooxidation reaction (BOR) is very complex; to date it remains poorly studied and understood on many electrocatalysts (most of them are in the form of metal nanoparticles supported on carbon black). In addition, recent studies reported the aggressiveness of the alkaline medium on the durability of conventional carbon-supported electrocatalysts, revealing a large loss of the active catalytic surface, mainly due to the detachment of nanoparticles from the carbon support. In this context, this thesis focused on three main areas of study: (i) the study of the BOR on palladium-based electrocatalysts in conditions close to the real operating conditions of the DBFC; (ii) the study of the impact of the anode structure on the overall performance of the DBFC, and (iii) the study of the degradation mechanism of noble metal electrocatalysts in alkaline environment. The experiments were carried out in close collaboration with the U.S. Naval Research Laboratory (Washington, USA).The results obtained showed that a high concentration of NaBH4 leads to a decrease of the reaction kinetics, due in part to poisoning of the catalytic surface. In addition, activity markers for the BOR have been proposed. Then, the use of catalysts-gradient electrodes proved to be a promising solution to better valorize the hydrogen produced via side reactions of the BOR. Finally, the use of Fourier transform infrared spectroscopy coupled with identical-location transmission electron microscopy enabled to detect the formation of carbonates during the accelerated stress test of carbon-supported noble metal electrocatalysts in alkaline medium, explaining, in part, the detachment of nanoparticles observed during the test
YOVANOVICH, MARCOS. "Oxidação eletroquímica do ácido fórmico em eletrólito ácido e básico utilizando eletrocatalisadores PtBi/C e PdBi/C preparados pelo método de redução via borohidreto de sódio adição rápida". reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26799.
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PtBi/C e PdBi/C foram preparados em diferentes razões atômicas (100:0, 90:10, 80:20, 70:30, 60:40 e 50:50) pelo método de redução via borohidreto de sódio (com adição total da solução de borohidreto em uma única etapa) utilizando H2PtCl6.6H2O, Pd(NO3)2, (BiNO3)3.5H2O como fonte de metais, Vulcan® (XC72-Cabot) como suporte de carbono e com uma carga metálica correspondente a 20% em massa. Os eletrocatalisadores obtidos foram caracterizados por difração de raios-X (DRX), microscopia eletrônica de transmissão (MET) e voltametria cíclica (VC). A atividade dos diferentes materiais preparados para a oxidação eletroquímica do ácido fórmico foi realizada em eletrólito ácido e alcalino utilizando-se as técnicas de voltametria cíclica, e cronoamperometria. Para estes estudos foi utilizado a técnica do eletrodo de camada fina porosa. A caracterização eletroquímica permitiu comparar o desempenho eletroquímico da platina e paládio, além de avaliar o benefício da presença do bismuto nas razões atômicas propostas. Os difratogramas de raio-X (DRX) confirmaram para todos os compostos de PtBi/C e PdBi/C a formação da estrutura cúbica de face centrada (cfc) característicos da rede cristalina da platina e do Paládio respectivamente. Outros picos encontrados foram associados a presença de fases de óxido de bismuto em ambos os compostos, PtBi/C e PdBi/C. A microscopia eletrônica de transmissão (MET) indicou que a presença de maiores teores de bismuto não acarretaram em aumento do tamanho médio da partícula. Os resultados eletroquímicos em meio alcalino indicaram que ainda é necessário uma otimização da concentração de ácido fórmico para que possamos observar melhores resultados quanto à adição de bismuto na platina ou paládio, no entanto os estudos em meio ácido mostraram o efeito benéfico da adição de bismuto tanto para platina quanto para o paládio.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Coche, Liliane. "Préparation et étude électrochimique d'électrodes modifiées par des films de polymères rédox : application à la catalyse électrochimique rédox". Grenoble 1, 1987. http://www.theses.fr/1987GRE10046.
Pełny tekst źródłaSOUZA, LETICIA L. de. "Oxidação direta do etileno glicol sobre catalisadores eletroquímicos binários à base de Pt, Pd, e Sn suportados em carbono para aplicação em células alcalinas". reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26934.
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Os catalisadores eletroquímicos binários de PtSn/C, PdSn/C e PtPd/C foram sintetizados em diferentes proporções pelo método da redução via borohidreto, posteriormente estes foram caracterizados por microscopia eletrônica de transmissão, difração de raios X, espectroscopia no infravermelho por transformada de Fourier (PtSn/C e PdSn/C) e energia dispersiva de raios X. As atividades eletroquímicas dos diferentes materiais preparados foram avaliadas por intermédio de voltametria cíclica, cronoamperometria e curvas de polarização em célula a combustível alimentada diretamente por etileno glicol em eletrólito alcalino. As curvas de densidade de potência indicaram que os catalisadores eletroquímicos contendo Sn e Pd são mais ativos para a reação de oxidação do etileno glicol, especialmente a composição 70%:30% - relação molar entre os metais suportados em carbono - dos catalisadores PtSn/C, PdSn/C e PtPd/C todos superando as medidas de potência do Pt/C. Este resultado indica que a adição de Sn e Pd favorece a oxidação do etileno glicol em meio alcalino. O melhor desempenho observado para os catalisadores eletroquímicos PtSn/C, PdSn/C e PtPd/C (70%:30%) poderia estar associado à sua maior seletividade quanto a formação de oxalato, ou seja , a formação deste produto resulta em um maior número de elétrons, por consequência em maiores valores de corrente.
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Ourari, Ali. "Étude de deux réactions d'électrocatalyse : hydrogénation électrocatalytique sur des films de polymères contenant des microparticules de métaux nobles et activation de l'oxygène par des complexes Mn(III) - bases de Schiff". Université Joseph Fourier (Grenoble ; 1971-2015), 1995. http://www.theses.fr/1995GRE10171.
Pełny tekst źródłaFan, Yu-Sin, i 方郁歆. "Anisotropic Palladium Nanocrystals as Electrocatalyst for Formic Acid Oxidation". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/06451449301030565710.
Pełny tekst źródła國立交通大學
材料科學與工程學系
98
In this thesis, we successfully synthesized various palladium (Pd) nanocrystals including nanoplates, octahedrons, porous nanocrystals, and hollow nanocrystals in the PVP-assisted chemical reduction process. The synthesis involved only the use of PdCl2 as the precursor, PVP as the reducing and stabilizing agents, and a specific salt like NaCl or NH4OH as the additive. By modulating the relevant reaction conditions such as the amount of PdCl2, the amount of additive, and the reaction temperature, we were able to obtain Pd nanocrystals with controllable morphologies. The four types of Pd nanocrystals exhibited notable electrocatalytic activities toward formic acid oxidation and hydrogen adsorption/desorption. Surface-enhanced Raman spectroscopy for the anisotropically-shaped Pd of nanoplates and octahedrons was also investigated to demonstrate their potential as an active substrate for Raman-sensitive analyte molecules.
Huang, I.-Jie, i 黃以捷. "Using block copolymer with palladium and iron metal precursor to synthesize electrocatalyst". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/hf39c4.
Pełny tekst źródła國立中央大學
化學工程與材料工程學系
105
In recent years, the fuel cells are considered to be very important green energy devices. Most of the commercial fuel cells are platinum-based electrocatalyst. This kind electrocatalyst has high oxygen reduction reaction (ORR) activity, but they also show many obvious disadvantages like scarcity, high cost and low tolerance toward methanol. To overcome this problem, we fabricate the palladium-iron-based alloy type of electrocatalysts. We developed a method to fabricate this catalysts by preparing poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) block copolymer (BCP) with Na2PbCl4 and FeCl3 metal precursor. Before pyrolysis, we conduct the cross-linked process with UV radiation under nitrogen (UVIN) for 6 hours. The UVIN-treated sample was pyrolyzed in a furnace for 1 hour with argon (Ar) gas to form carbon nanostructures. The morphologies, structure, composition, and elecreocatalytic activities of the material were characterized by atomic force microscope (AFM), field-emission scanning electron microscope (FESEM), cyclic voltammetry (CV) and rotating disk electrode (RDE). We can get high values for both the electron transfer number (n) and kinetic current density (jk). The onset potential for our sample is close to -0.1V. From these experimental results, we find that our palladium-iron-based electrocatalysts have good catalyst activities.
(10712736), Toma Bhowmick. "SYNTHESIS OF GOLD NANOPARTICLE CATALYSTS USING A BIPHASIC LIGAND EXCHANGE METHOD AND STUDY OF THEIR ELECTROCATALYTIC PROPERTIES". Thesis, 2021.
Znajdź pełny tekst źródłaNoble metal nanoparticles have been studied extensively as heterogeneous catalysts for electrocatalytic and thermal reactions. In particular, the support material for the catalytic species is known to play a role in influencing the geometric and electronic properties of the active site as well as its catalytic performance. Polycrystalline gold electrodes have been used as a support to modify the electrocatalytic behavior of adsorbed molecular species. Here, we have studied two electrocatalytic processes- the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR), using Au nanoparticle-based catalysts.
Transition metal dichalcogenides are well-known HER catalysts that show structure-sensitive catalytic activity. In particular, undercoordinated sulfur sites at the edges of bulk materials as well as amorphous clusters and oligomers tend to show the highest reactivity. The hydrogen adsorption energy of MoSx nanoclusters can be further tuned through the metallic support. Here, we synthesize colloidal Au@MoS42-, Au@WS42-and Au@MoS42--WS42- using a biphasic ligand-exchange method. The MoS42- and WS42- complexes show higher HER activity when supported on Au nanoparticles than on to a carbon control, illustrating the electronic role played by the support material.
In the second project, Au nanoparticle cores are utilized as supports for Pd submonolayer and monolayer surfaces in order to catalyze the two-electron reduction of O2 to generate hydrogen peroxide. Bulk surfaces of Pt and Pd are excellent catalysts for the four-electron reduction of O2 to H2O. In order to achieve high selectivity for H2O2, we postulate that the ensemble geometry of the Pd surface must be reduced to small islands or single atoms based on literature studies that have shown that large Pd ensembles are required for O–O bond cleavage. In this study, we synthesize several submonolayers surface coverages of Au@Pd core-shell nanoparticles using a biphasic ligand-exchange method. As the Pd coverage decreases from monolayer to submonolayer, the peroxide selectivity rises but is accompanied by an increase in catalytic overpotential. The highest peroxide selectivity was observed for 0.1 layers of Pd on Au, which likely exhibits the highest fraction of isolated atom and small cluster geometric ensembles of Pd.
Kukunuri, Suresh. "Palladium and Nickel Chalcogenides as Electrocatalysts". Thesis, 2016. http://etd.iisc.ac.in/handle/2005/2851.
Pełny tekst źródłaKukunuri, Suresh. "Palladium and Nickel Chalcogenides as Electrocatalysts". Thesis, 2016. http://etd.iisc.ernet.in/handle/2005/2851.
Pełny tekst źródłaSarkar, Arindam. "Synthesis and characterization of nanostructured palladium-based alloy electrocatalysts". 2009. http://hdl.handle.net/2152/6597.
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Chen, Kuan-Yuan, i 陳冠元. "Multi-Walled Nanotubes Supported Palladium and Gold in Electrocatalysis Applications". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/80640727904670759431.
Pełny tekst źródła大同大學
材料工程學系(所)
98
This study synthesizes the novel hybrid catalytic nanomaterials and investigates their structures and catalytic properties in electrocatalytic reaction. The purified multi-wall carbon nanotubes (MWCNTs) have acid functional groups and defects on their surface where metals or oxides are easy to attach. Because of the high thermal conductivity and specific surface area of MWCNTs, we are used MWCNTs as supporters in this study to support nano Pd or Au-Pd particles that synthesize by polyol process using PdCl2 and HAuCl4.4H2O as precursors. In this research, the effects of weight ratios of Pd and Au to purified MWCNTs on electrocatalytic activity for the oxidation of formic acid are investigated. The structures of nano hybrid catalysts are analyzed by X-ray diffraction (XRD) patterns. Thermogravimetry Analyzer (TGA) is used to determine the contents of metal catalyst in the nano hybrid materials. Scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) are applied to observe the morphologies, structures, sizes and dispersion of nano catalysts. According to the TEM images, the synthesized metal nanoparticles are uniformly dispersed on the surfaces of MWCNTs, and the diameter of these nanoparticles in nano hybrids is about 5~20 nm. The electrochemical analyses illustrate that Au(10wt%)/[Pd/MWCNTs(1:9)] catalyst exhibits higher activity and better stability than that of Pd/MWCNTs catalyst in formic acid electrooxidation. It indicates that the added Au improves dramatically on the performance of Pd-based catalysts in electrochemical reaction. Thus, hybrid Au-Pd/MWCNTs materials have potentially to be used in the direct formic acid fuel cell (DFAFCs) in the future.
Chen, Dai-Yan, i 陳玳延. "Multi-Walled Carbon Nanotubes Supported Palladium-based Material in Electrocatalysis Applications". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/82863778054925740788.
Pełny tekst źródła大同大學
材料工程學系(所)
97
The motivation of this study is to synthesis catalytic nanomaterials and to explore the structure and catalytic properties of the these materials used in electrocatalytic reaction. The purified multi-walled carbon nanotubes have the acid functional groups and defects on the surface that makes easy to attach metals or oxides on carbon nanotubes. High thermal conductivity and surface area of the multi-walled carbon nanotubes (MWCNTs) have been used as supporter to support nano Pd and Au-Pd particles by polyol process using PdCl3 and HAuCl4.4H2O as precursors. The preparation and characterization of palladium/multi-walled carbon nanotubes (Pd/MWCNTs) and gold/palladium/multi-walled carbon nanotubes (Au-Pd/MWCNTs) hybrid materials towards formic acid oxidation are examined in this research. The structures of the resulting nano-catalyst composite materials are analyzed by X-ray diffraction (XRD) patterns. Thermogravimetry Analyzer (TGA) is used to determine the contents of metal catalyst in the hybrid materials. Scanning Electron Microscope (SEM) and High Resolution Transmission electron microscope (HRTEM) are applied to image the morphologies, structures, sizes and the dispersion of nano catalysts. For the results of electrochemical oxidation reaction, the multi-walled carbon nanotubes supported palladium-based materials have the better electro-oxidation behavior and suppress the poison of CO on catalysts. From the saturation to the steady-state current experiment, it indicates the Au-Pd/MWCNTs catalyst has better catalytic performance with high steady state reaction current.
Zhao, Juan 1981. "Development and understanding of Pd-based nanoalloys as cathode electrocatalysts for PEMFC". Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-08-1813.
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Liu, Pei-Yu, i 劉姵余. "Synthesis and Characterization of Nanohybrid Platinum and Palladium/ N-doped TiO2/MWCNTs Electrocatalysts". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3xx3r7.
Pełny tekst źródła大同大學
材料工程學系(所)
106
Due to the shortage of fossil fuels and the serious environmental pollution, the development of excellent green alternative energy has become the current trend. The direct formic acid fuel cells (DFAFCs) have the characteristics of being non-toxic, non-flammable, convenient for storage and transportation, and so on. It becomes an important subject for current research and development. For a practical fuel cell, it requires low cost, high catalyst activity, and high stability. Therefore, in this study, the development of a good anode catalyst for direct formic acid fuel cells is the main research target. In order to improve the efficiency of the catalyst, this study does not use noble metals in alone, but also adds oxides to reduce the adsorption of carbon monoxide and avoid poisoning of the catalyst. This study prepared titanium dioxide (TiO2) by sol-gel method was carried out on the purified carbon nanotubes, and the conductivity of the TiO2 was enhanced by doping nitrogen using nitriding. Finally, the reduced metal platinum (Pt) and palladium (Pd) nanoparticles were supported on N-TiO2/MWCNTs and AO-MWCNTs by synchrotron radiation X-ray synthesis. Proposed two kinds of electrocatalytic catalyst support materials (AO-MWCNTs and N-TiO2/MWCNTs) to compare the electrocatalytic effects of noble metals of different support materials. For testing, we used the instruments of XRD, SEM, TEM, ICP and CV, etc. The XRD, SEM and TEM showed that the metal nanoparticles were successfully loaded on the modified carbon tube and the metal particles were about 4~6 nm in size; the electrochemical analysis showed that the 1.6Pt/18.4Pd/80MWCNTs and Pd/N-TiO2/MWCNTs has the best electrocatalytic stability.
Arenz, Matthias [Verfasser]. "Model electrodes for electrocatalysis : Ultrathin palladium films on Pt(111) / vorgelegt von Matthias Arenz". 2002. http://d-nb.info/966390350/34.
Pełny tekst źródłaChiou, Yuh-Jing, i 邱郁菁. "Electrocatalysis Applications of Palladium and Gold Catalysts Supported on Metal Oxide Modified Multi-Walled Carbon Nanotubes". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/00347803783944807580.
Pełny tekst źródła大同大學
材料工程學系(所)
99
For the application of direct formic acid fuel cell, Pd catalyst with some modification attracts the study attention for its electrocatalytic advantages. To benefit the catalytic performance and prevent the catalyst poison problem, this study develops Pd basis catalysts, which have solid solution phase with Au and ceria/ceria-zirconia modified MWCNTs substrate, by impregnation and polyol methods. The composition, structure and morphology are analyzed by ICP, XRD and FETEM, respectively. For Au-Pd bimetal catalysts, the formation of solid solution phase and the compositions of the catalysts are proved to be consistent with the initial designation. For MWCNTs modified by ceria or ceria-zirconia, both mesoporous structure of ceria/ceria-zirconia and the advanced breaking of MWCNTs in the impregnation process may cause the surface area increasing of MWCNTs. Zr doping may decrease the temperature of lattice oxygen desorption. The addition of metal can fill the defect of the substrate and decrease the surface area. Pd is the main dominant to promote the reaction and lower the reaction temperature in the TPD helium process. In electrocatalysis, Au-Pd solid solution can prevent the leaching of Pd in formic acid, while the oxide modified support can prevent catalyst poison. The prepared catalysts can totally convert CO between 150~250oC. More Pd can convert 100% CO at lower temperature. It can be considered that, both the formation of solid solution, Au-Pd, and the oxide modification of MWCNTs can decrease the activation energy of the catalyzing reaction and have better catalytic performance.
BAMBAGIONI, VALENTINA. "Design and development of palladium based electrocatalysts for direct alcohol fuel cells: the conversion of renewables into energy and chemicals". Doctoral thesis, 2011. http://hdl.handle.net/2158/545755.
Pełny tekst źródłaWise, Brent. "Addition of platinum to palladium-cobalt nanoalloy catalyst by direct alloying and galvanic displacement". Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-12-2451.
Pełny tekst źródłatext
Sarkar, Sujoy. "Electrocatalytic Studies on Layer-type Ternary Phosphochalcogenides and on the Formation of Nitride Phases". Thesis, 2014. http://etd.iisc.ac.in/handle/2005/3027.
Pełny tekst źródłaSarkar, Sujoy. "Electrocatalytic Studies on Layer-type Ternary Phosphochalcogenides and on the Formation of Nitride Phases". Thesis, 2014. http://hdl.handle.net/2005/3027.
Pełny tekst źródłaLubera, Justyna. "Wykorzystanie elektrokatalitycznego przeniesienia elektronu w układzie jod/jodki do przygotowania elektrolitów redoks zdolnych do szybkiej propagacji ładunku". Doctoral thesis, 2020. https://depotuw.ceon.pl/handle/item/3809.
Pełny tekst źródłaElectrochemical systems characterized by fast (reversible) charge transfer have a practical significance, particularly in electrochemical storage and conversion systems such as dye-sensitized solar cells (DSSC), redox flow batteries (RFB) and redox electrolyte-aided hybrid energy storage (REHES)). Moreover, development of above-mentioned, alternative energy technologies have crucial importance of protecting the environment. One of the most commonly used redox couples responsible for efficient electron transfer in energy storage and conversion systems is the iodine/iodide. Therefore, the first Chapter of this doctoral dissertation is focused on the general electrochemical properties of iodine and its electrochemical characterization in aqueous and organic solutions. The next part is dedicated to DSSC, where its individual components are discussed and particular attention is paid to the redox electrolytes containing iodine/iodide redox mediator. In addition, it should be emphasized that the energy generated by alternative energy sources, including DSSC, can be stored by converting it into chemical energy for example by using RFB or can be directly stored as electrical charge in electrochemical capacitors. Consequently, the next two Chapters of my dissertation focus on these two energy storage technologies. The main differences between RFB and traditional batteries and the resulting pros and cons of these devices are indicated. Farther the typical classification of flow batteries and the examples of the cells where the iodine/iodide redox couple is used as the catholyte are presented. The next part of the dissertation is devoted to the electrochemical capacitors. These include the detailed characteristics of double-layer-type systems, pseudocapacitors and hybrid capacitors, i.e. combining the electrochemical signature of batteries and conventional supercapacitors. A specific class of hybrid capacitors containing electrochemically active electrolyte (widely known as REHES - redox electrolyte-aided hybrid energy storage) is also characterized. These systems are often based on alkali metal iodides and exhibit an increased charge storage capacity as a result of reversible redox reactions of iodide ions occurring at the positive electrode/electrolyte interface. This PhD thesis also does not omit the basic issues related to the mechanism of charge transfer in thin electrode layers, bulk solid and semi-solid materials having mixed oxidation states. In order to submit a more complete study, detailed characterization of solid electrochemistry without contact with the external phase of the supporting electrolyte is also given. Moreover the emphasis is put on the utilization of microelectrodes in electrochemical characterization of solids. The following Chapter is focused on the increment of the reaction rate constant by inserting the catalyst into the system which allows the conversion of energy in the most efficient, reversible and cost-effective way. Next an electrocatalytic mediation as a specific kind of electrocatalysis is also discussed. The theoretical part of this PhD thesis is finished by brief description of the research methods used in the experimental part. The research described in the experimental part has been divided into four main Chapters. In order to enhance charge propagation within the system, firstly the utilization of Pt nanoparticles "three-dimensionally" distributed in a semi-solid ionic liquid containing iodine/iodide redox pair is described. It allows the induction of a chemical stage, breaking of the iodine-iodine bond in the I3 - molecule, which is responsible for limiting electron transfer in the system. The above mentioned concept has been demonstrated in both, diagnostic measurements which utilized solid-state electrochemistry and a practical set-up in a DSSC. Pd nanoparticles, as a cheaper alternative to Pt nanoparticles, are also proposed with the same redox electrolyte based on the ionic liquid to enhance charge transfer within the system. With reference to Pd nanoparticles three different electrochemical methods based on cyclic voltammetry, chronoamperometry and chronoculometry were used to calculate the effective diffusion coefficient and apparent concentration of redox centers. The used modifiers based on Pt and Pd nanoparticles have been subjected to physicochemical (SEM, TEM, EDS, zeta potential) and extended electrochemical characterization). The subsequent part of the research involves introducing the aforementioned modifiers into the electrolyte based on organic solvent (acetonitrile) with the possible simplest composition. The aim of such approach is to compare the mechanism of charge propagation in two different solutions with different viscosities. As an alternative to noble metal nanoparticles, the use of conductive polymers (more specifically poly (3,4-ethylene-1,4-dioxythiophene), PEDOT)) and carbonaceous materials (activated carbon) have also been proposed. The last part of the doctoral dissertation refers to the operation mechanism of hybrid capacitors containing iodine/iodide redox-based electrolyte by addressing their performance changes in time and with a type of stability test used. Two types of electrode materials with different morphology and charge storage mechanism were used in the construction of these devices, i.e. activated carbon and PEDOT. Both of these materials were characterized using different physicochemical techniques. Analysis of processes occurring during potentiostatic accelerating-ageing stability tests allowed to diagnose the causes of differences in the rate of self-discharge as well as to describe the parasitic reactions responsible for high internal leakage by proposing a new mechanism of charge/self-discharge in the halogene-based electrolytes used in supercapacitors.