Two-dimensional (2D) materials have attracted extensive research interest in recent years. Among them, graphene and the semiconducting transition metal dichalcogenides (TMDs) are considered as promising candidates for future device applications due to their unique atomic thickness and outstanding properties. The study on graphene and TMDs has demonstrated great potential to further push the scaling of devices into the sub-10 nanometer regime and enable endless opportunities of novel device architectures for the next generation. In this thesis, crucial challenges facing 2D materials are investigated from material synthesis to electronic applications. A comprehensive review of the direct synthesis of graphene on arbitrary substrates with an emphasis on the metal-catalyst-free synthesis is given, followed by a detailed study of the contact engineering in TMDs with a focus on the strategies to lower the contact resistance. Effective approaches have been demonstrated to solve these issues. These include: (1) metal-catalyst-free synthesis of graphene on various insulating substrates; (2) Fermi level pinning observed in TMDs and integration of graphene contact to lower the contact resistance; and (3) application of metal-insulator-semiconductor (MIS) contact in TMD field-effect transistors (FETs). First, a direct low-temperature synthesis of graphene on insulators without any metal catalysts has been realized. The effects of carbon sources, NH3/H2 concentrations, and insulating substrates on the material synthesis have been systematically investigated. Graphene transistors based on the as-grown material have been fabricated to study the electronic properties, which can further confirm the nitrogen-doped graphene has been synthesized from the electrical characterizations. Then electronic devices focusing on the semiconducting TMDs has been studied. The Fermi level pinning has been observed and studied in WS2 FETs with four metal materials. A novel method of using graphene as an insertion layer between the metal and TMDs has been proven to effectively reduce the contact resistance. Owing to the benefit of tuning the graphene work function via the electric field, the contact resistance can further be reduced. Finally, the effectiveness of MIS contacts in WS2 FETs has been demonstrated. A thickness dependence research has been conducted to find the optimal thickness of the inserted insulator. Moreover, the possible physical mechanism of how this MIS contact reduces the contact resistance in 2D materials has been discussed.

The global warming has increased with unprecedented levels during the last couple of decades and the trend is uprising. The construction industry is responsible for nearly 10% of all carbon emissions, mainly due to the increasing global population and the large demand for housing and civil infrastructure. Concrete, which is the most used construction material worldwide, is found in every type of building as it provides long term structural stability, support and its main constituent cement, is very cheap. Consequently, due to the raising concerns of high average temperatures, the research community started investigating new, innovative methods for substituting cement with 'greener' materials whilst at the same time improving the intrinsic properties of concrete. However, the manufacturing complications and logistics of these materials make them unfavourable for industrial applications. A novel and truly revolutionary method of enhancing the performance of concrete, thus allowing for decreased consumption of raw materials, lies in nanoengineering the cement crystals responsible for the development of all mechanical properties of concrete. Graphene, a two-dimensional sheet of carbon atoms arranged in a hexagonal lattice, is the most promising nanomaterial for composites' reinforcement to this date, due to it's exceptional strength, ability to retain original shape after strain, water impermeability properties and non-hazardous large scale manufacturing techniques. I chose to investigate the addition of liquid-phase exfoliated graphene suspensions for concrete reinforcement, aiming to improve the fundamental mechanical properties of the construction material and therefore allowing the industry to design buildings using less volume of base materials. First, the method of liquid exfoliation of graphene was developed and the resulting water suspensions were fully characterised by Raman spectroscopy. Then, concrete samples were prepared according to British standards for construction and tested for various properties such as compressive and flexural strength, cyclic loading, water impermeability and heat transport. A separate, in-depth, study was carried out to understand the formation and propagation of micro-structural cracks between the concrete's internal matrix planes, and graphene's impact on total fracture capacity and resistance of concrete. Lastly, multiple experiments were performed to investigate the microcrystallinity of cement hydration products using X-Ray diffraction. In general, all experimental results show a consistent improvement in concrete's performance when enhanced with graphene on the nanoscale level. The nanomaterial improves the mechanical interlocking of cement crystal, thus strengthening the internal bonds of the composite matrix. This cheap and highly scalable method for producing and mixing graphene with concrete turns it into the first truly applicable method for industrial applications, with a real potential to have positive impact on the global warming by decreasing the production of concrete.

Um dispositivo eletroquímico foi desenvolvido para a determinação simultânea de sulfametoxazol (SMX) e trimetoprim (TMP), utilizando voltametria de pulso diferencial e um eletrodo de carbono vítreo (GC) modificado com o compósito óxido de grafeno reduzido (rGO) e nanopartículas de prata (AgNPs), sintetizados por dois métodos: químico e o eletroquímico. A morfologia e o comportamento eletroquímico dos eletrodos GC modificados com os compósitos rGO/AgNPs (método químico) e rGO-AgNPs (método eletroquímico) foram caracterizados por microscopia eletrônica de varredura acoplada a um canhão de elétrons (FEG-SEM) e voltametria cíclica (CV). Essas técnicas demostraram que, nos dois métodos utilizados, o óxido de grafeno (GO) foi modificado com as AgNPs, e que o compósito sintetizado pelo método eletroquímico apresentou uma melhor dispersão das nanopartículas, resultando em um aumento da área superficial quando comparado ao compósito rGO/AgNPs. Assim, o eletrodo GC/rGO-AgNPs foi avaliado e otimizado na determinação simultânea de SMX e TMP e atingiu limites de detecção de 0,6 µmol L-1 para o SMX e 0,4 µmol L-1 para o TMP. O dispositivo eletroquímico proposto, GC/rGO-AgNPs, foi aplicado com sucesso na determinação simultânea de SMX e TMP em águas residuárias. / An electrochemical device was developed for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) using differential pulse voltammetry, and a glassy carbon electrode (GC) modified with the reduced graphene oxide composite (rGO) and silver nanoparticles (AgNPs), synthesized by two methods: chemical and electrochemical. The morphology and the electrochemical behavior of the GC electrode modified with composite rGO/AgNPs (chemical method) and rGO-AgNPs (electrochemical method) were characterized by scanning electron microscopy coupled to an electron gun (FEG-SEM) and cyclic voltammetry (CV). These techniques demonstrated that, in both methods, the graphene oxide (GO) was modified with AgNPs, and the composite synthesized by the electrochemical method showed a better dispersion of the nanoparticles, resulting in an increased surface area when compared to the composite rGO/ AgNPs. Thus, the GC/rGO-AgNPs electrode was evaluated and optimized for simultaneous determination of SMX and TMP and achieved detection limits of 0,6 µmol L-1 to SMX and 0,4 µmol L-1 for the TMP. The proposed electrochemical device, GC/rGO-AgNPS, was successfully applied for the simultaneous determination of SMX and TMP in wastewater.

O grafeno, material com duas dimensões (2D), formado por átomos de carbono hibridizados em sp2, tem atraído muita atenção da comunidade científica devido às propriedades elétricas, térmicas e mecânicas excepcionais que este material apresenta. Nanopartículas (NPs) de metais e de óxidos metálicos têm sido incorporadas sobre a estrutura do grafeno com o objetivo de obter materiais compósitos. Este trabalho teve por objetivo principal desenvolver uma nova rota para a preparação de compósitos de grafeno/NPs metálicas e de óxidos metálicos pelo método do poliol modificado, em etapa única. O óxido de grafeno (GO) foi sintetizado pelo método Hummers modificado e reduzido e esfoliado pelo processo pioliol modificado para obtenção do grafeno. Ajustou-se a metodologia proposta para que o GO obtido pudesse ser utilizado diretamente no meio reacional do processo poliol sem a necessidade de secagem e redispersão. Foram testadas diversas condições de síntese do grafeno variando-se a presença e tipo de surfactante, o solvente e diferentes condições de aquecimento. As variações de síntese permitiram observar que a presença do surfactante oleilamina aumenta a capacidade redutora do sistema e inibe a formação de outras estruturas de carbono além do grafeno e taxas de aquecimento menores favorecem a formação de grafeno em detrimento destas outras estruturas, enquanto patamares de temperatura intermediários levam à formação dessas estruturas secundárias de carbono. As sínteses foram também adaptadas para a obtenção de compósitos de grafeno/NPs de FePt e Fe3O4. Estas sínteses foram realizadas de duas maneiras: com os precursores metálicos e o GO presentes no balão desde o início da síntese e com os precursores metálicos presentes no balão desde o início da síntese e hot injection do GO. Para os compósitos, as sínteses realizadas em benzil éter (BE) favoreceram a formação de partículas. Para os compósitos de grafeno/NPs de Fe3O4, observou-se que a quantidade de precursor de Fe é crucial para a formação das NPs. Os resultados indicaram que a metodologia empregada foi muito eficiente para produção de grafeno e de compósitos de grafeno/NPs em etapa única e o processo poliol se mostrou muito versátil, de maneira que os resultados obtidos indicam que é possível obter compósitos de grafeno com qualquer sistema de NPs que venham a ser sintetizadas pelo processo poliol, apenas pelo ajuste das condições de síntese, em etapa única. / Graphene, a two dimensional material, composed only by sp2 hybridized carbon atoms, have attracted much attention of the scientific comunity due to the exceptional electrical, thermal and mechanical properties this material presents. Metallic and metal oxide nanoparticles (NPs) have been incorporated over graphene structure in order to obtain composite materials. The main goal of this work was to develop a new synthetic route to obtain graphene and metallic and metal oxide NPs composites, in one step. Graphene oxide (GO) was sinthesized by the modified Hummers method and exfoliated and reduced by the modified polyol process to obtain graphene. The proposed methodology was adjusted for the obtained GO to be used directly in the polyol process reactional means, not being necessary to dry and to redisperse the material. Several synthesis conditions were tested to obtain graphene, varying the presence of the surfactant and its type, solvent and heating rates. The synthesis diversity let us observe that the presence of oleylamine improved the reducing capacity of the system and it inhibited other carbon structures formation besides graphene. Also, smaller heating rates favor graphene formation to the detriment of these other structures, whereas intermediate temperature plateaus lead to the formation of carbon secondary structures. The synthesis were also adapted in order to obtain graphene/NPs of FePt and Fe3O4 composites. These synthesis were performed in two ways: both metallic precursors and GO present in the flask since the begining of the synthesys and only methalic precursors present in the flask since the begining of the synthsys, with a GO hot injection. Regarding the composites, synthesis performed in benzyl ether (BE) favor the particles formation. And specifically on the graphene/NPs of Fe3O4 composites, it was observed that Fe precursor quantity is decisive on the NPs formation. The results indicated that the employed methodology was very efficient to produce graphene and graphene/NPs composites in one step. And the polyol process proved to be very versatile, thereby the obtained results indicate it\'s possible to obtain graphene/NPs composites, in one step, with any NPs system that can be synthesized by the polyol process, only by adjusting the synthesis condition.

L’effet Hall quantique (EHQ), observé par exemple dans des gaz bidimensionnels d’électrons (2DEGS) à basse température et sous fort champ magnétique, a révolutionné la métrologie des résistances car il permet d’obtenir un étalon quantique de résistance qui ne dépend que de e et h (respectivement la charge de l’électron et la constante de Planck). Une des missions des métrologues est de développer les étalons en améliorant leurs performances ou en les rendant plus facile à mettre en oeuvre (travaillant à plus haute température ou plus faible champ magnétique). Dans ce contexte, la physique du graphène suscite l’intérêt pour une application en métrologie. Une monocouche de graphène est une feuille d’un seul atome d’épaisseur constituée d’atomes de carbone disposés en nid d’abeille. Une bicouche de graphène est formée par empilement de deux monocouches. Les écarts en énergie entre les premiers niveaux de Landau dans la monocouche et dans la bicouche sont supérieurs par rapport à ceux dans GaAs ce qui rend l’EHQ dans le graphène plus robuste et laisse envisager le développement d’un étalon plus pratique. Durant ma thèse, nous avons mis en place un protocole de fabrication de barres de Hall en graphène exfolié comprenant un repérage optique, des lithographies électroniques, la métallisation, la gravure plasma… L’utilisation de substrat de silicium oxydé en surface rend possible l’utilisation d’une grille en face arrière. En outre la géométrie des échantillons répond au mieux aux critères métrologiques (canal central large, prises de tension bien définies, …). A basse température, le dopage résiduel obtenu après le recuit in situ est de l’ordre de 3-4x1011 cm-2. Les mobilités sont proches de 3000 cm2/(V.s) et 4000 cm2/(V.s) respectivement pour les échantillons monocouche et bicouche à la fois pour les électrons et les trous. Le transport mésoscopique a été caractérisé à basse température par des mesures de localisation faible et de fluctuations universelles de conductance. La longueur de cohérence que nous avons extraite est de l’ordre de 0.5 µm à 1.5 K. La résistance des contacts mesurée en régime d’EHQ est plutôt faible (typiquement quelques ohms). L’EHQ a été étudié en détail à basse température (300 mK < T <1.5 K) et sous fort champ magnétique (jusqu’à 18.5T) à la fois dans la monocouche et la bicouche en mesurant de manière précise la résistance de Hall (RH) et la résistance longitudinale (Rxx). Les mesures fines de RH sont réalisées à l’aide d’un pont de comparaison basé sur un Comparateur Cryogénique de Courant ; elles consistent à comparer indirectement l’EHQ dans l’échantillon de graphène à l’EHQ obtenu dans une barre de Hall en GaAs/AlGaAs qui est supposée fournir la valeur exacte RH/2. Nos mesures révèlent un accord entre la résistance de Hall dans le graphène et la valeur attendue avec une incertitude de quelques 10-7. Au plus faible courant et dans l’état de dissipation minimale (Rxx→0), nous avons obtenu un accord avec une incertitude relative de 3.10-7. Ce niveau de précision est principalement limité par la petite taille de nos échantillons et par les inhomogénéités de la densité qui y sont présents, ces deux caractéristiques amenant de faibles courants de rupture de l’EHQ (1-2 µA). Toutefois, nos résultats sont à ce jour les tests les plus précis concernant l’EHQ dans du graphène exfolié et les premiers tests sur une bicouche. Ils confirment le potentiel de l’EHQ dans le graphène pour une application en métrologie. / The quantum Hall effect (QHE) observed in two dimensional electron gases (2DEGs) at low temperature and under high magnetic induction, has revolutionized the resistance metrology because it leads to a universal and very reproducible quantum resistance standard only dependent on e and h (respectively the electron charge and Planck's constant). One of the metrologists' missions is to develop standards with improved performances and to notably make them more practical, working for example at higher temperature or lower magnetic induction. In this context, graphene physics could be very interesting for metrological applications. Monolayer graphene is a one atom thick layer of carbon atoms condensed in a honeycomb lattice. A bilayer graphene consists in two stacked monolayers. Larger energy spacings between the first Landau Levels in monolayer and in bilayer than in GaAs make the QHE in graphene more robust and give hope that more practical standards could be developed. During the PhD, we have set a protocol up in order to fabricate exfoliated graphene based Hall bars, including location with an optical microscope, e-beam lithography, metallization, plasma etching… Backgated using oxidized silicon wafers the devices were designed to fulfill at best the metrological requirements (large conduction channel, well defined voltage probes…). At low temperature, the typical charge carrier residual doping obtained after the annealing process was 3-4x1011 cm-2. Mobilities were close to 3000 cm2/(V.s) and 4000 cm2/(V.s) respectively for the monolayer and the bilayer based device both for holes and electrons. Mesoscopic transport was characterized at low temperature by weak localization and universal conductance fluctuations (UCF) measurements. The phase coherence length deduced was about 0.5 µm below 1.5 K. The resistance of the contacts, measured in the QHE regime, appeared to be rather low (typically few ohms). The QHE was investigated in details at low temperature (300 mK < T <1.5 K) and high magnetic field (up to 18.5 T) in both monolayer and bilayer graphene by refined measurements of the Hall resistance (RH) and also of the longitudinal resistance (Rxx). The accurate measurements of RH were performed using a Cryogenic Current Comparator based resistance bridge. They consist in an indirect comparison between the QHE in graphene and the QHE obtained in a GaAs based Hall bar, supposed to deliver the expected value RH/2. Our measurements showed an agreement of the Hall resistance in graphene with the expected value within some parts in 107. At the lowest biasing current and in the lowest dissipation state (where Rxx→0) it is possible to demonstrate an agreement within an uncertainty of 3 parts in 107. That accuracy is essentially limited by the small size, and the poor homogeneity of the carrier density of the graphene electronic systems, both acting for a very reduced breakdown current of the QHE (1-2 µA). Nevertheless these results are the most accurate tests of the QHE performed in exfoliated graphene and the first universality test of the QHE with bilayer graphene. They confirm the potential of the QHE in graphene for the metrological application.

It has become increasingly apparent that the future of next generation of electronic devices can and will rely on graphene nanoribbons. Graphene nanoribbons and sister structures showcase several key properties that can address the emerging need of terahertz science and technology, and break through the many technological limits on conventional semiconductor electronics operating in the terahertz spectrum. In this thesis, we focus on the study of the terahertz nonlinear optical response of metallic armchair graphene nanoribbons and sister structures using a k.p model and time dependent perturbation theory. We find that these nanoribbons exhibit a stronger interband optical response, and a smaller critical field strength (of the order of 10 kV/m) than does 2D single layer graphene. We demonstrate that finite ribbon size, spatial profile of the applied terahertz radiation field, polarization of the applied terahertz radiation, a small band gap opening, and application of a superlattice potential are several ways to tune the strong terahertz nonlinear optical response of metallic armchair graphene nanoribbons. The major contributions of this thesis include: 1) developes of a simpler method compared to other sophisticated methods of the terahertz nonlinear optical interband response of metallic armchair graphene nanoribbons; 2) extends the method in the characterization of various quantum size effects, elliptically polarized radiation field, small gap opening and superlattice on the terahertz optical response of these nanoribbons; 3) The versatility of the tunability showed in the terahertz nonlinear response of metallic armchair nanoribbons and sister structures will help advance the development of the nonlinear terahertz armchair graphene nanoribbon opto-electronic and photonic technology.

Thesis (M.Sc. (Chemistry)) -- University of Limpopo, 2019. / The concept of sustainable energy development is one of the crucial topics of the 21st century. It has evolved into a guiding principle for a liveable future world where human needs are met while maintaining balance with the environment. In this regard, hydrogen technology is a promising alternative energy source since it does not produce undesirable greenhouse gas (CO2). In order to place hydrogen energy into practical applications, there are certain problems that need to be addressed, these include the efficient production and storage of hydrogen. Currently, hydrogen is mostly produced from conventional processes such as steam reforming of fossil fuels, gasification and water splitting (photo/electrochemical and thermochemical). Among these methods, electrochemical water splitting is identified as a noble process to produce clean hydrogen gas and monitor all processes through hydrogen evolution reactions (HER). The entire HER processes are sluggish in nature and cathodic electrocatalysts are utilised to accelerate the process. Hence, in this work, we present highly active graphene oxide/metal organic framework (GO/MOF) and palladium (Pd) supported GO/MOF electrocatalysts for HER. GO/MOF was prepared through impregnation method of MOF and GO, whereas Pd@GO/MOF composite was synthesised using electroless Pd deposition on GO and followed by impregnation method of direct mixing of Pd@GO and MOF. The structural, morphological and electrochemical properties of the synthesised materials (GO/MOF and Pd@GO/MOF) were characterised by X-ray diffraction (XRD), Fourier transform infrared (FTIR), simultaneous thermogravimetric analysis (STA), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), high resolution transmission electron microscopy/Energy dispersive x-ray spectroscopy/selected area electron diffraction (HRTEM/EDX/SAED) and cyclic voltammetry (CV). XRD, FTIR, TGA and DSC results revealed the presence of GO on MOF confirming the formation of composites. The SEM/EDS and HRTEM/EDX/SAED results confirmed the presence of octahedral structure of MOF in the Pd@GO sheet-like structure, elemental composition and crystallinity of the synthesised materials. Furthermore, the electrocatalytic efficiency of GO/MOF and Pd@GO/MOF composites on HER was studied using three important parameters (exchange current density, Tafel slope and charge transfer coefficient) calculated from Tafel analysis. The GO/MOF and Pd@GO/MOF composites showed excellent HER activity at 0.45 mol.L-1 H2SO4 withexchange current densities of 25.12 A.m-2 and 24.5 A.m-2, Tafel slopes of 116 mV/dec and 123 mV/dec, and transfer coefficients of 0.49 and 0.52, respectively. These observed results are consistent with theory, thus suggesting the Volmer reaction as the limiting mechanism at high concentration. However, at low concentration both composites showed an increase in the Tafel slope and transfer coefficient, suggesting the reaction order of Volmer reaction coupled with either Heyrovsky or Tafel reaction. The proposed reaction order was further supported by slope of logarithm of current as a function of pH and Pourbaix diagram. The composites demonstrated the enhancement turnover frequency (TOF) values in this order MOF <GO/MOF <Pd@GO/MOF. The large TOF value of 7.81 mol H2.s-1 in the case of Pd@GO/MOF was due the H2 spillover effect as a result of the presence of Pd nanoparticles. The fabricated composites displayed high activity, good stability and excellent tolerance to the crossover effect, which may be used as a promising catalyst in electrochemical hydrogen production and storage technology via hydrogen evolution reaction.

Graphene, two dimensional sheet of carbon atoms has recently gained attention as some of its properties are promising for electronics applications e.g. higher mobility that translates to higher operating frequency for devices geared towards radio frequency applications. Excellent optical transmittance combined with its semi metallic behavior makes it an important material for transparent contacts in solar cells. To bring graphene to the production level, synthesis methods are needed for its growth on wafer scale. It has been shown that chemical vapor deposition (CVD) is one of the techniques that can potentially synthesize wafer scale graphene. Recently copper has gained popularity as an important substrate material for graphene growth due to its lower carbon solubility, which allows better control over number of graphene layers. Here we report optimization of graphene growth on copper foils with our home made atmospheric pressure chemical vapor deposition (APCVD) setup. Graphene growth on copper under APCVD was non self-limiting similar to other reports. It was found that apart from growth parameters surface texture plays a very important role in graphene growth. In fact, few layer and bilayer graphene were obtained on the regions where copper surface was not uniform, confirmed by Raman spectroscopy. To improve copper surface texture thin layer of copper film was evaporated by electron beam evaporation before the graphene growth process. After this modification, monolayer graphene was obtained on areas as large as 300 um × 300 um confirmed by Raman area maps. Graphene transfer procedure was also optimized so that graphene on metal surface could be transferred to insulating substrate

Palladium-catalyzed carbon-carbon cross-coupling reactions have emerged a broadly useful, selective and widely applicable method to synthesize pharmaceutical active ingredients. As currently practiced in the pharmaceutical industry, homogeneous Pd catalysts are typically used in cross-coupling reactions. The rational development of heterogeneous catalysts for cross-coupling reactions is critical for overcoming the major drawbacks of homogeneous catalysis including difficulties in the separation, purification, and quality control process in drug production. In order to apply heterogeneous catalysis to flow reactors that may overcome this limitation, the catalyst must be strongly bound to a support, highly stable with respect to leaching, and highly active. While the primary role of supports in catalysis has been to anchor metal particles to prevent sintering and leaching, supports can also activate catalytic processes. In this study, by using a xi combined theoretical and experimental method, we probed the effect of graphene as support in the complex reaction cycle of Suzuki reactions. The density functional theory study provides a fundamental understanding of how a graphene support strongly binds the Pd nanoparticles and act as both an efficient charge donor and acceptor in oxidation and reduction reaction steps. Theoretical investigations prove that the Pd-graphene interaction promotes electron flow between the metal cluster and the defected graphene to reduce reaction barrier. The ability for graphene to both accept and donate charge makes graphene an unusually suitable support for multi-step catalytic processes that involve both oxidation and reduction steps. The computer-aided catalyst design with the atomic precise accuracy demonstrates the Pd/graphene catalyst can be further optimized and the first-row transition metal nanoparticles have great potential to replace Pd to catalyze the Suzuki reaction. The corresponding experimental study shows that the method to immobilize the Pd nanoparticles on the graphene is crucial to increasing the reactivity and stability of the resulted catalyst. A comparison of the activation energy and turn over frequency for a series of supported and homogeneous catalysts indicates that exposing palladium-graphene to defect inducing microwave radiation results in dramatically lower activation energies and higher turnover frequencies. Furthermore, the heterogeneity tests demonstrate the Suzuki reactions are carried out on the surface of the immobilized Pd nanoparticle agreeing with the theoretical results. A method to engineer the 2-D graphene support to a 3-D structure to minimize the re-stacking and agglomeration of the graphene lattice will also be introduced in this study.

Nanoparticles are involved in a broad range of applications, including heterogeneous catalysis. Nanoparticles tend to quickly lose their well-defined shapes and facets due to aggregation under duress such as heat. A series of highly studied materials are explored as support materials for nanoparticle supports. These supports include metal-organic frameworks (MOF), graphene oxide (GO), and a MOF-PRGO (partially reduced graphene oxide) hybrid. The inclusion of a support with the palladium increased lifespan of the catalyst by separation of nanoparticles. The choice of support material not only allowed for supporting of palladium nanoparticles, but allowed for rational catalyst synthesis in order to design catalysts with improved catalytic activity. CO oxidation, vanillin hydrogenation, and Suzuki cross coupling were studied. For the CO oxidation reaction, a cerium-based MOF, Ce-MOF, is shown to increase activity of palladium nanoparticles by capturing reactant gases and acting as an oxygen reservoir that cycles between (III) and (IV) states while transferring oxygen to palladium nanoparticles at the Pd/Ce-MOF interface. A hybrid Ce-MOF-PRGO was synthesized to increase the surface area and acidity of Ce-MOF materials and was shown to be active for vanillin hydrogenation. Smaller rod-like Ce-MOF crystals were observed, indicating intercalation of crystals on GO. Zirconium-based MOF UiO-66-NH2 was acidified via incorporation of tungstophosphoric acid (HPW), which increased the selectivity of products by adjusting the mechanistic pathway. GO was partially functionalized with aromatic amines to improve the coupling of bromobenzene and phenylboronic acid. Small amounts of aromatic amines increased the Pd(0) content and decreased nanoparticle size.