Malignant melanoma cancer is the sixth common cancer diagnosed in the United States. Surgery, chemotherapy and radiation are some of the successful techniques in killing tumor cells. However, in these techniques, it is not easy to distinguish tumor cells from the healthy once which inadvertently get exposed to chemical agent/radiation. Therefore it is required to develop an anticancer agent which selectively kills the cancer cells, while still protecting the normal tissues. In our preliminary work, we have shown that Dextran (1000Da) coated Cerium oxide nanoparticles (Dex-CNPs) selectively kills the cancer cells (50% killing at a concentration of 150μM) without inducing toxicity to the normal cells. However, the mechanism involved on how CNPs/Dex-CNPs attain the selectivity and efficiently kill the tumor cells is still unknown. In this study we have synthesized Dextran coated ceria nano particles (Dex- CNPs) with different surface oxidation state ratio (Ce4+/Ce3+). This will provide an in depth understanding of the key chemical and physical properties of the system that can improve its efficacy. The varied surface oxidation of the particles is achieved by exposing Dex-CNPs to light which initiates a color change from dark to pale yellow indicating the reduction of Ce4+ to Ce3+. Interestingly we have found that the DexCNPs exposed to light have reduced cytotoxicity towards squamous cell carcinoma cell line (CCL30) compared to the protected once. Characterization of the same revealed that Dex- CNPs exposed to light have decreased Ce4+ /Ce3+ surface oxidation ratio compared to the other. This provides more insight in useful synthesis of Dex-CNPs in terms of storage and handling. In summary, higher Ce4+ /Ce3+ surface oxidation ratio is more efficient in hindering tumor growth by effectively hindering the tumor-stoma interaction.

The application of Cerium oxide nanoparticles (CNPs) for therapeutic purposes requires a stable dispersion of nanoparticles in biological environment. The objective of this study is to tailor the properties of polyelectrolyte coated CNPs as a function of molecular weight to achieve a stable and catalytic active dispersion. This was achieved by coating CNPs with polyacrylic acid (PAA) which increased the dispersion stability of CNPs and enhanced the catalytic ability. The stability of PAA coating was analysed using the change in the Gibbs free energy computed by Langmuir adsorption model. The adsorption isotherms were determined using soft particle electrokinetics which overcomes the challenges presented by other techniques. The Gibbs free energy was highest for PAA coated CNPs by 250 kg/mole indicating the most stable coating. The free energy for PAA 100 kg/mole coated CNPs is 85% lower than the PAA250 coated CNPs. This significant difference is caused by the strong adsorption of PAA100 on CNPs. Catalytic activity of PAA-CNPs is accessed by the catalase enzymatic activity of nanoparticles. The catalase activity was higher for PAA coated CNPs as compared to bare CNPs which indicated preferential adsorption of hydrogen peroxide induced by coating. Apart from PAA coating the catalase activity is also affected by the structure of the coating layer.

Metal oxide nanoparticles constitute an important class of nanomaterials which has have received tremendous attention due to their distinct, specific activities comparison to their bulk. Among these, cerium oxide nanoparticles (CeNPs) have displayed outstanding promise across a wide range of applications owing to their unique redox properties. Given that the physical and chemical characteristics of nanomaterials are significantly influenced by their morphologies and sizes, the development of well-controlled synthesis methods for CeNPs holds great importance in both scientific research and industrial applications. This dissertation seeks to peer into the formation of CeNPs in solution through wet chemical synthesis. Additionally, antioxidant properties of CeNPs were examined to explore the potential use of facet CeNPs in gene delivery and promoting wound healing for diabetic. The beginning of this work provides introduction and summary of some common concepts widely used in understanding of nanoparticles formation. In chapter two and three, the spontaneous hydrolysis behavior of tetravalent cerium salts in aqueous systems were studied in detail to understand the influence of synthesis condition on the nucleation kinetic and morphology evolution in the course of growth of nanoparticle. The results obtained from these studies offer constructive insights into designing a straightforward and controlled synthesis strategy for producing nanoclusters and faceted nanoparticles through wet chemical methods. Furthermore, in chapter five, we examine the impact of faceted CeNPs on biomolecule conjugation and their performance in gene delivery for the regulation of abnormal diabetic wound healing. Overall, by taking advantage of the intrinsic properties of tetravalence cerium salt, this work highlights how manipulation of spontaneous hydrolysis could lead to formation of particles with different nanostructure and physicochemical properties.

The rise of antimicrobial resistance demands the development of more rapid screening methods for the detection of antimicrobial resistance in clinical samples to both give the patient the proper treatment and expedite the treatment of patients. Cerium oxide nanoparticles may serve a useful role in diagnostics due to their ability to exist in a mixed valence state and act as either oxidizing agents or reducing agents. Considering that cerium oxide nanoparticles have been shown to shift in absorbance upon oxidation, a useful method of antimicrobial resistance detection could be based on the oxidation of cerium oxide nanoparticles. Herein, an assay is described whereby cerium oxide nanoparticle oxidation is a function of glucose metabolism of bacterial samples in the presence of an antimicrobial agent. Cerium oxide nanoparticles were shown to have an absorbance in the range of 395nm upon oxidation by hydrogen peroxide whereas mixed valence cerium oxide nanoparticles lacked an absorbance around 395nm. In the presence the hydrogen peroxide-producing glucose oxidase and either increasing concentrations of glucose or bacterial medium supplemented with increasing concentrations of glucose, cerium oxide nanoparticles were shown to increase in absorbance at 395nm. This oxidation assay was capable of measuring differences in the absorbance of E. coli and S. aureus samples grown in the presence of inhibitory and non-inhibitory concentrations of ampicillin in as little as six hours. Therefore, this cerium oxide nanoparticle oxidation assay may be very useful for use in clinical laboratories for the detection of antimicrobial resistance due to the relatively low cost, no requirement for specialized equipment and, most importantly, the reduced incubation time of the assay to as little as six hours compared to current gold standard antimicrobial resistance detection methods that require 24 hours.; This assay may thus also help partially circumvent the issue of knowledge of antimicrobial resistance in infected patients before prescribing improper regimens.

Cerium and zirconium oxides are important materials in industrial catalysis. Particularly, the great advances attained in the past 30 years in controlling levels of gaseous pollutants released from internal combustion engines can be attributed to the development of catalysts employing these materials. Unfortunately, oxides of sulfur are known threats to the longevity of many catalytic systems by irreversibly interacting with catalytic materials over some time period. In this work, polycrystalline cerium-zirconium mixed-metal-oxide (MMO) solid solutions of various molar ratios were synthesized. High resolution x-ray photoelectron spectroscopy (XPS) was used to characterize the model system. The spectral data was examined for revelation of the surface species that form on these metal oxides after insitu exposures to sulfur dioxide at various temperatures. The model catalysts were exposed to sulfur dioxide using a custom modified in-situ reaction cell. A reliable sample platen heater was designed and built to allow the exposure of the model system at temperatures up to 673 K. The results of this study demonstrate the formation of sulfate and sulfite adsorbed sulfur species. Temperature and compositional dependencies were displayed, with higher temperatures and ceria molar ratios displaying a larger propensity for forming surface sulfur species. In addition to analysis of sulfur photoemission, the photoemission regions of oxygen, zirconium, and cerium were examined for the materials used in this study before and after the aforementioned treatments with sulfur dioxide. The presence of surface hydroxyl groups was observed and metal oxidation state changes were probed to further enhance the understanding of sulfur dioxide adsorption on the synthesized materials. Palladium loaded mixed-metal oxides were synthesized using a unique solid-state methodology to probe the effect of palladium addition on sulfur dioxide adsorption. Microscopic characterization of the wafers made using palladium-loaded MMO materials provide justification for using this material preparation method in surface science studies. The addition of palladium to this model system is shown to have a strong effect on the magnitude of adsorption for sulfur dioxide on some material/exposure condition combinations. Ceria/zirconia sulfite and sulfate species are identified on the palladium-loaded MMO materials with adsorption sites located on the exposed oxide sites.

No description available.

Cerium oxide nanoparticles have the unique ability to accept and donate electrons, making them powerful antioxidants. Their redox nature is due to oxygen defects in the lattice structure, which are more abundant at the nanoscale. Reactive oxygen species (ROS) are pro-oxidants whose presence is increased during periods of inflammation in the body. ROS damage tissues and cellular function by stripping electrons from proteins, lipids, and DNA. We investigated the ability of nanoceria to quench ROS in vitro and in vivo, and examined the biodistribution and biocompatibility of nanoceria in murine models. Nanoceria was internalized in vitro by macrophages, is non-toxic at the concentrations we investigated, and proteins, mRNA, and oxidative markers of ROS were abated with nanoceria pretreatment in immune stimulated cells as measured by western blot, real time RT PCR, and Greiss assay respectively. In vivo, nanoceria was deposited in the spleen and liver, with trace amounts in the lungs and kidneys as determined by ICP-MS. Using IVIS in vivo imaging, it appeared that nanoceria deposition occurred in lymph tissue. Histology grades show no overt pathology associated with nanoceria deposition, although white blood cell (WBC) counts were generally elevated with nanoceria treatment. Nanoceria suspect particles were seen in lysosomes from kidney samples of IV injected mice in HRTEM images. Lastly, IV nanoceria treatment appears to reduce markers of oxidative stress in mice treated with carbon tetrachloride (CCl4) to induce ROS production. Taken together, our data suggest that nanoceria treatment has the potential to reduce oxidative stress. / Master of Science

This dissertation focuses on the assessment and development of heterogeneous catalysts for the deperoxidation of cyclohexyl hydroperoxide and oxidation of cyclohexane, which will be based in metal oxides and gold nanoparticles. For this endeavour a multidisciplinary approach will be used combining theoretical chemistry, kinetic studies and synthesis and characterisation of materials. The starting choice for the catalyst to carry out the process is supported gold nanoparticles. The approach of this dissertation is to first model the mecha- nism of cyclohexyl hydroperoxide decomposition and oxidation of cyclohexane on gold nanoparticles by theoretical calculations, and use these findings to synthesise efficient heterogeneous catalysts which will be subsequently tested and optimised experimentally. But as it will be seen, some metal oxides are active rather than acting as mere supports, which will also be studied both theoretical and experimentally. Each chapter has a specific focus and constitutes a strand of the overall goal: Chapter 1 provides an introductory background on the topics that this dissertation lies upon: oxidation of cyclohexane, heterogeneous catalysis and catalysis by gold and metal oxides. Chapter 2 outlines the objectives of the thesis, formulating the relevant hypotheses of this research and the subsequent validation tests. Chapter 3 exposes the methodology with a brief conceptual background that has been used to carry out this work. Chapter 4 is the first chapter dealing with results. It consists in a theoretical study using density functional theory of the reaction mechanism over different models of gold nanoparticles, in order to study the influence of several parameters on their catalytic activity: the particle size, atom coordination, and presence of additional species like oxygen atoms and water. Chapter 5 uses the findings found in chapter 4 to drive the synthesis of supported gold nanoparticles. It consists in a experimental study of gold-based catalysts, which is combined with a theoretical study which takes into account an additional variable: the support. Chapter 6 exploits one of the findings of chapter 5. One of the supports used for anchoring the gold nanoparticles is active by itself, namely cerium oxide. This chapter comprises an experimental work about its activity, studying parameters like particle size, morphology and the effect of doping. Chapter 7 continues with the catalytic activity of cerium oxide-based materials, but now from a theoretical point of view. It first presents a systematic study of the parameters relevant for the proper quantum mechanical description of cerium oxide, which is followed by a mechanistic study on different models. Chapter 8 outlines the conclusions obtained in this dissertation, present- ing them in a summarised way. Even though each chapter presents its corresponding conclusions at its end, this chapter groups them all in a structured way for the reader's convenience, so a global view of the project can be swiftly grasped. The results herein further the knowledge of heterogeneous catalysis for the oxidation of cyclohexane, one of the most important industrial reactions, and which continues to be a challenge. Although the ultimate goal is to develop an industrial catalyst, the dissertation also aims to show how computational chemistry can drive the design of novel materials, and how it can help to understand catalytic reactions at the atomic level. / El presente trabajo se centra en el estudio y desarrollo de catalizadores heterogéneos para la desperoxidación de ciclohexil hidroperóxido y la oxidación de ciclohexano, basados en óxidos metálicos y nanopartículas de Au. Para lograr tal objetivo se ha usado un enfoque multidisciplinar, que combina química teórica y estudios cinéticos, a la vez que síntesis y caracterización de materiales. El candidato inicial para llevar a cabo el proceso consiste en partículas de Au soportadas. El camino a seguir pasa primero por modelizar el mecanismo de descomposición de ciclohexil hidroperóxido y oxidación de ciclohexano mediante cálculos teóricos, y utilizar el conocimiento generado por este estudio para dictar la síntesis de catalizadores heterogéneos, comprobando y optimizando posteriormente su actividad de forma experimental. Sin embargo, como será visto a lo largo de este trabajo, algunos óxidos metálicos dejan de lado su papel como mero soporte físico para las partículas de Au y son activos por sí mismos. Tal hecho será estudiado tanto teórica como experimentalmente. Cada capítulo tiene un objetivo específico, y es a su vez una parte del objetivo global de esta investigación: El capítulo 1 provee al lector de una breve introducción a los temas sobre los que yace este trabajo: oxidación de ciclohexano, catálisis heterogénea y catálisis mediante Au y óxidos metálicos. El capítulo 2 expone de una forma breve y concisa los objetivos de esta investigación, formulando la hipótesis de partida y los correspondientes experimentos para su validación. El capítulo 3 describe la metodología utilizada junto a una explicación de los fundamentos en los que se basa cada técnica. El capítulo 4 es el primer capítulo que discute los resultados obtenidos en esta investigación. Se trata de un estudio usando la teoria del funcional de densidad para investigar el mecanismo de reacción del proceso sobre diferentes modelos teóricos de Au, con el objetivo de comprender la influencia de diversos factores en la actividad catalítica, tales como el tamaño de partícula, la coordinación de los á'tomos de Au y la presencia de especies adicionales como átomos de O y agua. El capítulo 5 hace uso de los resultados obtenidos en el estudio anterior, y los utiliza para dirigir la síntesis de nanopartículas soportadas de Au. Se trata de un estudio experimental en el que se investigan diversos factores que pueden afectar a su actividad catalítica. Este estudio se combina a su vez con uno de tipo teórico en el que se tiene en cuenta la influencia del soporte en la actividad catalítica de las particulas de Au. El capítulo 6 se basa en uno de los resultados obtenidos en el capítulo 5. Uno de los soportes utilizados para anclar las partículas de Au resulta de por sí activo: el CeO2. Su notable actividad para catalizar este proceso exige un estudio en mayor profundidad, el cual se lleva a cabo en este capítulo. Parámetros como el tamaño de particula, la morfología de superficie y el dopaje entre otros se investigan en este punto. El capítulo 7 sigue la estela del trabajo anterior sobre CeO2, pero ahora desde el punto de vista de la química teórica. Presenta primero un estudio sistemático de parámetros relacionados con la mecánica cuá'ntica que afectan al CeO2, con el objetivo de alcanzar una descripción satisfactoria de los modelos teóricos para este óxido. Tras esto, se lleva a cabo un estudio del mecanismo de reacción en dichos modelos de CeO2, a fin de comprender el origen de su actividad catalítica. El capítulo 8 presenta de forma estructurada y concisa todas las conclusiones que se han sacado a raíz de los resultados obtenidos. Aún a pesar de que cada capítulo presenta sus correspondientes conclusiones al final, aquí se presentan de una forma agrupada a comodidad del lector, para que pueda obtener de forma ágil una visión global de los resultados de esta investigación. / Aquest treball es centra en l'estudi i desenvolupament de catalitzadors hetero- genis per a la desperoxidació de ciclohexil hidroperòxid i la oxidació de ciclohexà, basats en òxids metàl·lics i nanopartícules de Au. Per aconseguir aquest objectiu s'ha utilitzat un enfocament multidisciplinari, en el qual es combinen química teòrica i estudis cinètics amb síntesi i caracterització de materials. El candidat inicial per dur a terme el procés consisteix en partícules de Au suportades. El camí a seguir passa primer per modelitzar el mecanisme de descomposició del ciclohexil hidroperòxid i la oxidació de ciclohexà mitjançant càlculs teòrics, i utilitzar el coneixement generat per aquest estudi per dirigir la síntesi de catalitzadors heterogenis, comprovant i optimitzant posteriorment la seua activitat de forma experimental. No obstant això, com es veurà al llarg d'aquest treball, alguns òxids metàl·lics deixen de costat el seu paper com a suport físic de les partícules de Au y són actius per si mateixos. Aquest fet s'ha estudiat tant teòrica com experimentalment. Cada capítol té un objectiu específic i és al mateix temps una part de l'objectiu global d'aquesta recerca: El capítol 1 proporciona al lector una breu introducció als temes tractats en aquest treball: oxidació de ciclohexà, catàlisi heterogènia i catàlisi mitjançant Au i òxids metàl·lics. El capítol 2 exposa d'una forma breu i concisa els objectius d'aquesta investigació, formulant la hipòtesi inicial i els corresponents experiments per a la seua validació. El capítol 3 descriu la metodologia utilitzada conjuntament amb una explicació dels fonaments en els quals es basa cada tècnica. El capítol 4 és el primer capítol que discuteix els resultats obtinguts en aquesta investigació. Es tracta d'un estudi usant la teoria del funcional de densitat per investigar el mecanisme de reacció del procés en diferents models teòrics de Au, amb l'objectiu de comprendre la influència en l'activitat catalítica de diversos factors, com ara la grandària de partícula, la coordinació dels àtoms de Au i la presencia d'espècies addicionals, com àtoms de O i aigua. El capítol 5 fa ús dels resultats obtinguts en l'estudi anterior, i els utilitza per dirigir la síntesi de nanopartícules suportades de Au. Es tracta d'un estudi experimental en el qual s'investiguen diversos factors que poden afectar a la seua activitat catalítica. Aquest estudi es combina amb un altre de caràcter teòric en el qual es té en compte la influència del suport en la activitat catalítica de les partícules de Au. El capítol 6 es basa en un dels resultats obtinguts en el capítol 5. Un dels suports utilitzats per fixar les partícules de Au resulta de per si actiu: el CeO2. La seua notable activitat per catalitzar aquest procés demana un estudi de major profunditat, el qual es duu a terme en aquest capítol. Paràmetres com la grandària de partícula, la morfologia de superfície i el dopatge, entre altres, s'investiguen en aquest punt. El capítol 7 continua l'estudi anterior sobre el CeO2, però ara des del punt de vista de la química teòrica. Presenta en primer lloc un es- tudi sistemàtic de paràmetres relacionats amb la mecànica quàntica que afecten al CeO2, amb l'objectiu d'aconseguir una descripció satisfactòria pels models teòrics d'aquest òxid. Després, es duu a terme un estudi del mecanisme de reacció en aquests models de CeO2, a fi de com- prendre l'origen de la seua activitat catalítica. El capítol 8 presenta de forma estructurada i concisa totes les conclusions que s'han extret arran dels resultats obtinguts. Encara que cada capí- tol presenta les seues corresponents conclusions al final, ací es presenten d'una forma agrupada per a la comoditat del lector, per què puga obtindre de forma àgil una visió global dels result d'una forma agrupada per a la comoditat del lector, per què puga obtindre de forma à / López Auséns, JT. (2016). From Quantum Mechanics to Catalysis: Studies on the oxidation of alkanes by gold and metal oxides [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/76806

The fate of nanoparticulate cerium oxide from the diesel fuel catalyst Envirox was studied from its presence in the additive to its transformations during combustion through its exposure to plants and soils using a broad range of analytical techniques. Envirox is a fuel-borne catalyst comprised of nanoparticles of cerium oxide suspended in kerosene. The particles suspended in Envirox were confirmed by synchrotron X-ray diffraction, dynamic light scattering, and electron microscopy to be 5-7 nm crystals of CeO2 present as 15 nm aggregates. Significant changes to the particles were induced by the combustion process, resulting in 50-300 nm euhedral crystals of CeO2 in the exhaust as discovered using high resolution transmission electron microscopy. Single particle electron diffraction of the emitted cerium oxide particles showed evidence of ordered oxygen vacancies, indicative of a superstructure. Variations in the engine operating load resulted in no significant differences in the emitted cerium oxide particles. The mobility through soils and impacts on the plant Brassica napus (dwarf essex rape) of the emitted cerium oxide were compared to small and large CeO2 nanoparticles as well as diesel particulate matter emissions with very low cerium. The small CeO2 nanoparticles exhibited high mobility through soils and significant uptake and translocation in the plants. The large CeO2 nanoparticles showed extremely low mobility in soils and no significant increase in cerium anywhere in the plants. Cerium emissions from a diesel engine utilizing Envirox was found to have moderate mobility through the soils as well as an increased association with the roots of the plants, though translocation of the cerium into the aboveground biomass was not statistically significant. Despite uptake and translocation of some materials by B. napus, exposure to these cerium sources at 100 ppm Ce in the topsoil showed no significant impacts on the growth or overall health of the plants when compared to unexposed control samples. This dissertation shows that CeO2 nanoparticles employed as catalysts suspended in diesel fuel are altered during their use resulting in changes to their mobility and interaction upon entering the environment. This dissertation lays the groundwork for a new approach to nanotoxicology. / Ph. D. / Understanding the environmental impacts – and subsequently the impacts on mankind – of the use of nanomaterials is an enormously complex problem. The bottomup approach, whereby one can predict impacts from fundamental principals, is not practical because nanotechnology implementation into products is occurring far too rapidly and it is impossible for environmental toxicologists to keep pace. The properties of a nanomaterial are controlled by small changes to its physical/chemical properties that can be tuned to suit many different practical applications. During their use and subsequent release into the natural environment, nanomaterials are exposed to incredibly complex spaces that are capable of modifying the original nanomaterial still further. Thus, the originally produced nanomaterial will continue to evolve, and therefore change in its interaction with biotic and abiotic systems. In this dissertation, we examine the use of nanoparticulate cerium oxide in fuelborne catalysts as a case study. As a fuel-borne catalyst, nanoparticulate cerium oxide is employed to reduce carbon dioxide (a greenhouse gas and contributor to global climate change) and particulate matter (a known carcinogen) emissions from combustion in a diesel engine. Fuel-borne catalysts achieve this through the suspension of cerium oxide nanoparticles in the fuel, which go through the combustion process and exit the tailpipe with the rest of the diesel exhaust. Concerns over the emission of this emerging contaminant have resulted in its limited market penetration. Here we show that the nanoparticulate cerium oxide in fuel-borne catalysts is substantially altered by the combustion process and is emitted as significantly larger particles in the exhaust. We suspected that the emitted cerium oxide would have different behavior in the environment from previously studied, laboratory synthesized cerium oxide nanoparticles. The behavior of emitted cerium oxide was compared with that of laboratory synthesized cerium oxide nanoparticles by exposure to the plant Brassica napus. The exposure experiments showed that cerium oxide emitted from the combustion of a fuel-borne catalyst did indeed behave differently in the environment, though none of the exposures proved toxic to the plants at the realistic concentrations utilized in the study.

Nanocrystalline cerium oxide thin films on metal and semiconductor substrates have been fabricated with a novel electrodeposition approach - anodic oxidation. X-ray diffraction analysis indicated that as-produced cerium oxide films are characteristic face-centered cubic fluorite structure with 5 ~ 20 nm crystal sizes. X-ray photoelectron spectroscopy study probes the non-stoichiometry property of as-produced films. Raman spectroscopy and Scanning Electron Microscopy have been applied to analyze the films as well. Deposition mode, current density, reaction temperature and pH have also been investigated and the deposition condition has been optimized for preferred oriented film formation: galvanostatic deposition with current density of -0.06 mA/cm2, T > 50oC and 7 < pH < 10. Generally, potentiostatic deposition results in random structured cerium oxide films. Sintering of potentiostatic deposited cerium oxide films leads to crystal growth and reach nearly full density at 1100oC. It is demonstrated that in-air heating favors the 1:2 stoichiometry of CeO2. Nanocrystalline cerium oxide powders (4 ~ 10 nm) have been produced with anodic electrochemical synthesis. X-ray diffraction and Raman spectroscopy were employed to investigate lattice expansion phenomenon related to the nanoscale cerium oxide particles. The pH of reaction solution plays an important role in electrochemical synthesis of cerium oxide films and powder. Cyclic voltammetry and rotation disk electrode voltammetry have been used to study the reaction mechanisms. The results indicate that the film deposition and powder formation follow different reaction schemes. Ce(III)-L complexation is a reversible process, Ce3+ at medium basic pH region (7~10) is electrochemically oxidized to and then CeO2 film is deposited on the substrate. CE mechanism is suggested to be involved in the formation of films, free Ce3+ species is coordinated with OH- at high basic pH region (>10) to Ce2O3 immediately prior to electrochemically oxidation Ce2O3 to CeO2. CeO2 / montmorillonite nanocomposites were electrochemically produced. X-ray diffraction and Raman spectroscopy illustrate the retaining of FCC structure for cerium oxide. Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry of composites indicate the insertion of montmorillonite platelets into the structural matrix of cerium oxide. Sintering study of the nanocomposites demonstrates that low concentration of montmorillonite platelet coordination into cerium oxide matrix increases crystal growth rate whereas high concentration of montmoillonite in nanocomposites retards the increase of crystallite size during the densification process.