Dans ce travail, nous nous sommes intéressés à la synthèse et à la caractérisation de matériaux à base d'argiles naturelles en provenance d'Algérie et de Tunisie, pouvant être utilisés en tant que catalyseurs dans l'oxydation de polluants organiques par les réactions Fenton et photo-Fenton. Nous avons également optimisé les paramètres réactionnels (quantité de catalyseur, concentration en polluant...) dans le but d'améliorer les performances catalytiques de ces derniers. En effet, l'oxydation de polluants organiques récalcitrants par des réactions de type Fenton est considérée comme l'une des techniques les plus performantes parmi les procédés d'oxydation avancée (POA). Elle permet d'aboutir dans certains cas au stade ultime de l'oxydation qui est la minéralisation (transformation en CO₂ et H₂O). La caractérisation des argiles à l'état brut par différentes techniques physico-chimiques montre qu'en plus des matériaux argileux, il existe quelques oxydes métalliques dans toutes les argiles étudiées, avec des proportions plus ou moins variées. En particulier, la smectite a montré une contenance assez importante en fer. Les argiles synthétisés montrent une très bonne performance catalytique en un minimum de temps (2 heures de réaction). Le catalyseur à base de smectite calciné à 450°C et tamisé donne le meilleur rendement catalytique. Cette activité peut être expliquée par la forte teneur en fer ainsi qu'à la combinaison entre le choix de la taille des particules et la température de calcination de la smectite. La caractérisation de ce catalyseur a montré que ce matériau mésoporeux contenait une quantité de fer (III) stabilisée dans la structure par le fait de la calcination. / In this study, we are interested to the synthesis and charaterization of materials based on natural clays from Algeria and Tunisia, usable as catalysts in the oxidation of organic pollutants by the Fenton's and photo-Fenton's reaction. We have also optimized the reaction parameters (amount of catalyst, concentration of pollutant...) in order to improve the catalytic performance of these catalysts. Indeed, the oxidation of recalcitrant organic pollutants by Fenton-type reactions is regarded as one of the most effective method amongst the advanced oxidation process (AOPs). It can lead in some cases to the total mineralization of pollutants (conversion into CO₂ and H₂O). The caracterization of the raw clays various physicochemical methods shows that, in addiction to clay minerals, there are some metallic oxides in all studied clays, with varied proportions. Especially, smectite showed a fairly significant iron capacity. The synthesized clays show a good catalytic performance in minimum of time (2 hours of reaction). The smectite catalyst, sieved and calcined at 450°C gives the best performance. This activity can be explained by the high content of iron as well as the combination of the choice of particle size and the calcination temperature of the smectite. The caracterization of this catalyst, showed that this mesoporous material contains an amount of iron (III) stabilized in the structure by the fact of calcination.

Light yellow, air-sensitive single-crystals of the rhodium(III) orthoperiodato K₈[Rh(IO₆)₂]OH·3H₂O were synthesized starting from Rh₂O₃ and KIO₄. The reaction was carried out in a potassium hydroxide hydroflux with a molar water-base ratio of 1.8 at 200°C. Single-crystal X-ray diffraction revealed a triclinic crystal structure (space group P1). The most striking feature of the structure is the [Rh(IO₆)₂]⁷⁻ anion, a linear sequence of three face-sharing octahedra. It can be interpreted as a rhodium(III) cation coordinated by two orthoperiodato groups. A water molecule and a hydroxide ion form an associate (H₃O₂)⁻ .Together with other water molecules, they connect the [Rh-(IO₆)₂]⁷⁻ anions via hydrogen bridges to form layers. Upon heating, the compound first loses its crystal water, then the iodine is gradually reduced before evaporating during the final decomposition step, which results in K₀.₆₃RhO₂. In K₈[Rh-(IO₆)₂]OH·3H₂O, the unusually short Rh/III-I/VII distance of only 276.38(1) pm should allow direct charge transfer in the [Rh(IO6)₂]⁷⁻ anion. An electron-poor rhodium cation, accessible from the side, could be the active center in the rhodiumcatalyzed oxidation of unsaturated organic molecules by periodate.

Abstract The releases of chlorinated volatile organic compounds (CVOCs) are controlled by strict regulations setting high demands for the abatement systems. Low temperature catalytic oxidation is a viable technology to economically destroy these often refractory emissions. Catalysts applied in the oxidation of CVOCs should be highly active and selective but also maintain a high resistance towards deactivation. In this study, a total of 33 different γ-Al2O3 containing metallic monoliths were studied in dichloromethane (DCM) and 25 of them in perchloroethylene (PCE) oxidation. The active compounds used were Pt, Pd, Rh or V2O5 alone or as mixtures. The catalysts were divided into three different testing sets: industrial, CVOC and research catalysts. ICP-OES, physisorption, chemisorption, XRD, UV-vis DRS, isotopic oxygen exchange, IC, NH3-TPD, H2-TPR and FESEM-EDS were used to characterise the catalysts. Screening of the industrial catalysts revealed that the addition of V2O5 improved the performance of the catalyst. DCM abatement was easily affected by the addition of VOC or water, but the effect on the PCE oxidation was only minor. Based on these screening tests, a set of CVOC catalysts were developed and installed into an industrial incinerator. The comparison between the laboratory and industrial scale studies showed that DCM oxidation in an industrial incinerator could be predicted relatively well. Instead, PCE was always seen to be oxidised far better in an industrial unit indicating that the transient oxidation conditions are beneficial for the PCE oxidation. Before starting the experiments with research catalysts, the water feed was optimised to 1.5 wt.%. Besides enhancing the HCl yields, water improved the DCM and PCE conversions. In the absence of oxygen, i.e. during destructive adsorption, the presence of water was seen to have an even more pronounced effect on the HCl formation and on the catalysts’ stability. In the DCM oxidation, the addition of the active compound on the catalyst support improved the selectivity, while the enhancing effect on the DCM conversion was only small. The high acidity together with the increased reducibility was seen to lead to an active catalyst. Among the research catalysts Pt/Al2O3 was the most active in the DCM oxidation. With PCE the addition of the active compound proved to be very beneficial also for the PCE conversion. Now Pt and Pd supported on Al2O3-CeO2 were the most active. The enhanced reducibility was seen to be the key feature of the catalyst in PCE oxidation. / Tiivistelmä Klooratuille orgaanisille hiilivedyille (CVOC) on asetettu tiukat päästörajoitukset niiden haitallisten vaikutusten takia. Tästä johtuen myös puhdistusmenetelmien tulee olla tehokkaita. Katalyyttinen puhdistus on teknologia, jolla nämä usein vaikeasti käsiteltävät yhdisteet voidaan taloudellisesti tuhota. Käytettävien katalyyttien tulee olla aktiivisia ja selektiivisiä sekä hyvin kestäviä. Tässä työssä tutkittiin yhteensä 33 erilaista γ-Al2O3-pohjaista hapetuskatalyyttiä metyleenikloridin (DCM) käsittelyssä, niistä 25 testattiin myös perkloorietyleenin (PCE) hapetuksessa. Aktiivisina metalleina katalyyteissä käytettiin platinaa, palladiumia, rhodiumia ja vanadiinia yksin tai seoksina. Katalyytit jaettiin kolmeen ryhmään: teolliset-, CVOC- ja tutkimuskatalyytit. Aktiivisuuskokeiden lisäksi katalyyttejä karakterisoitiin ICP-OES-, fysiorptio-, kemisorptio-, XRD-, UV-vis DRS-, isotooppivaihto-, IC-, NH3-TPD-, H2-TPR- ja FESEM-EDS-pintatutkimusmenetelmillä. Koetulokset osoittivat, että vanadiini paransi teollisuuskatalyyttien aktiivisuutta ja selektiivisyyttä. VOC-yhdisteen tai veden lisäys paransi DCM:n hapettumista, mutta PCE:n hapettumiseen niillä ei ollut vaikutusta. Testien perusteella kehitettiin CVOC-katalyytit, jotka asennettiin teolliseen polttolaitokseen. Laboratoriossa ja teollisuudessa tehdyissä testeissä havaittiin, että DCM:n hapettuminen oli laboratoriokokeiden perusteella ennustettavissa. Sen sijaan PCE hapettui teollisuudessa aina paljon paremmin kuin laboratorio-olosuhteissa. Tämä osoittaa, että muuttuvat hapettumisolosuhteet vaikuttivat positiivisesti PCE:n hapettumiseen. Veden määrä syöttövirrassa optimoitiin 1,5 %:iin ennen tutkimuskatalyyttien testausta. Selektiivisyyden lisäksi vesi paransi DCM:n ja PCE:n konversiota. Hapettomissa olosuhteissa, ts. tuhoavien adsorptiokokeiden aikana, vesi paransi reaktion selektiivisyyttä HCl:ksi ja CO2:ksi vielä entisestään. Tämän lisäksi vesi lisäsi katalyytin stabiilisuutta. DCM:n hapetuksessa aktiivisen metallin lisäys paransi selektiivisyyttä, mutta sen sijaan vaikutus DCM:n konversioon oli hyvin pieni. Tulokset osoittivat, että aktiivisella DCM:n hapetuskatalyytillä tulee olla korkea happamuus ja hyvä pelkistyvyys. Pt/Al2O3 oli testatuista tutkimuskatalyyteistä aktiivisin. PCE:n hapetuksessa aktiivisen metallin lisäys paransi selektiivisyyden lisäksi huomattavasti myös konversiota. Katalyytin lisääntyneen pelkistymiskyvyn todettiin olevan keskeisin ominaisuus PCE:n hapettumisessa. Pt/Al2O3-CeO2 ja Pd/Al2O3-CeO2 olivat tutkimuskatalyyteistä aktiivisimpia.

Dans cette étude, la nucléation, la croissance, la morphologie et la réactivité de nanoparticules Au, Cu et AuCu sont examinées sur support rutile TiO2 (110) stoechiométrique, réduit et hydraté. En premier lieu, la nucléation a été modélisée via l’adsorption et la diffusion d’atomes Au et Cu, à l’aide de calculs de type théorie de la fonctionnelle de la densité (DFT), et de diagrammes d’énergie libre en condition réaliste.Les résultats DFT+U ont montré le rôle promoteur des espèces hydroxyles en surface sur la nucléation, en accord avec les mesures expérimentales de microscopie STM. Ensuite, les propriétés thermodynamiques de croissance et de coalescence de clusters Au et Cu (de 1 à 38 atomes) ont été étudiées par une approche systématique qui a déterminé précisément la stabilité relative d’un grand nombre de structures, tout en soulignant la différence de compétition nucléation/croissance entre les deux métaux. Pour des tailles de particules comprises entre 38 et 201 atomes, et des morphologies variées, la stabilité absolue d’agrégats purs Au et Cu et de nanoalliages AuCu a été évaluée à l’aide de calculs d’énergie de surface. Cette approche a révélé l’existence de relations linéaires entre composition chimique et stabilité. Enfin, la réactivité de nanoparticules Au, Cu et AuCu a été examinée suivant deux aspects : le dépôt de clusters de 38 atomes sur support rutile stoechiométrique, et l’adsorption du monoxyde de carbone à l’interface entre le métal et le support.Cette adsorption est une étape clé pour la réaction d’oxydation du CO ; un procédé important en catalyse hétérogène. / In this study, the nucleation, growth, morphology and reactivity of Au, Cu and AuCu nanoparticles have been examined on rutile TiO2 (110) stoiciometric, reduced and hydrated supports. First, the nucleation has been modeled via the adsorption and diffusion of Au and Cu atoms, thanks to density functional theory (DFT) calculations, and free energy diagrams in realistic conditions. DFT+U results have shown the promotor role of surface hydroxyl species on the nucleation, in agreement with STM experimental measurements.Then, the growth and coalescence thermodynamic properties for Au and Cu clusters (from 1 to 38 atoms) have been investigated with a systematic approach which has determinated precisely the relative stability for a large number of structures, and has underlined the difference for the competition between nucleation and growth between the two metals. For particles in the range 38-201 atoms and varied morphologies, the absolute stability of Au and Cu aggregates and AuCu nanoalloys has been evaluated through surface energy calculations. This approach has revealed the existence of linear relations between the chemical composition and the stability.Finally, the reactivity of Au, Cu and AuCu nanoparticles has been examined following two aspects : the deposition of 38 atoms clustered on the stoichiometric rutile support, and the adsorption of carbon monoxide at the interface between the metal and the support. This adsorption is a key step for the CO oxidation reaction ; an important process in heterogeneous catalysis.

This diploma thesis is focused on the design of technological modifications of the existing industrial unit „waste-to-energy“, used for thermal treatment of process waste gases containing VOC and CO while flue gas is produced. The main objective of the existing unit modification is to improve its operating parameters considering economy, ecology and energy utilization. In the first part, the current industrial plant was presented with all necessary process data. Furthermore, all the key equipment used for the waste gases treatment or for the utilization of waste heat was identified. In the main part of the thesis there are performed modifications of the existing unit including the technology of existing heat exchangers intensification, the design of new and more efficient heat exchangers and finally the catalytic oxidation technology implementation for the decomposition of pollutants contained in the waste gas. The result of the thesis is a technical, economic and ecological comparison of the proposed technological modifications with the existing operation.

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Water polluted by recalcitrant organics, such as methylene blue (MB), can be treated with the Fenton reaction. The Fenton reaction degrades the pollutants through catalytic oxidation. Unsupported iron oxide nanoparticles (IONPs) were used as catalysts in this study. Iron oxide nanoparticles were synthesised using a precipitation-oxidation method and effects of various preparation parameters on the shape, size and catalytic activity of the iron oxide nanoparticles were studied. Parameters investigated include preparation temperature, type and amount of precipitating agent. The precipitating agents used are sodium hydroxide, tetramethyl ammonium hydroxide (TMAOH), tetraethyl ammonium hydroxide (TEAOH) and ethylamine. The iron oxide nanoparticles were found to be spherical for most of the preparation conditions as determined by TEM. However, irregular flower-like shapes (hexagonal with rod extensions) were obtained when the amounts of the TMAOH and TEAOH bases were more than the stoichiometric amounts. The nature and amount of precipitating agent also influenced the degree of particle agglomeration and growth, with an increase in alkyl chains in the base giving lesser agglomeration. The preparation temperature did not influence the nanoparticles’ size when NaOH was used as a precipitating agent. In contrast, when an amine was used as a precipitation agent, caused a slight increase in the size of the nanoparticles. Different crystal phases like hematite, magnetite, maghemite and goethite-hematite mixture were identified in the X-ray diffractograms. UV-Vis spectroscopy showed that all the catalysts were red-shifted except for B3 sample, which was blue-shifted from the bulk materials. The highest catalytic activities were obtained when NaOH was used as a precipitation agent instead of amine since catalyst has shown to contain the traces amounts of the base used on the surface. The lower catalytic activities for the catalysts prepared using amines may be due to amines adsorbed on the surface and blocking the catalytic active sites. FTIR spectra showed the presence of trace amounts of ammine functional groups on the nanoparticles No correlation was found between the crystallite size and the Fenton catalytic activity of the catalyst. In the same vein, operational parameters such as the amount of H2O2 and temperatures did not show a direct effect on the Fenton catalytic efficiency. Kinetic studies show that the degradation of methylene blue followed the first-order models for all the catalysts prepared with NaOH. Overall, the study shows that different preparation parameters had an effect on the size, shape, phase and the catalytic performance of the synthesised IONPs.

There are three major problems affecting efficiency in the catalytic oxidation of ammonia for obtaining nitric acid in an industrial plant: the limited life of gauzes, the low efficiency of the catalyst after a few months of operation, and finally, the necessity of recovering as much quantity of precious metals as possible. The first point to study in order to control the process and extend the useful life of the catalyst should be the correct characterization of the deactivated system. Therefore, this research is a systematic study about the performance of the catalytic recovering systems in nitric acid plants for all industrial pressures. In addition, it intends to cover the need of updating the knowledge in this field. The results obtained in this study with the support of SEM, EDX, XPS and AAS techniques, allow us to reach the following conclusions: The extremely critical conditions in which the activation pretreatment takes place cause important structural variations in the material surface. Beyond that, significant PtO2 losses and subsequent enrichment in RhO2 occur in a campaign in a high pressure plant, and mean while a continuous surface reconstruction is taking place. In contrast, an enrichment in Rh0 occurs in a lower pressure plant. In all situations, the deactivation is associated to a decrease in the Platinum content, more active than Rhodium. The getter mechanism in the recovering gauzes is directional and consists in the absorption of PtO2 (or Pt0) on the surface of the Palladium-based wires. Next, the PtO2 reduces itself to Pt0 and forms the Pt-Pd alloy. The part of volatile Platinum and Palladium oxides which gest through the recovering pack, as well as the particles of Rh2O3 carried away mechanically, settle in the heat exchangers line and in the Platinum filter of the high pressure plant. The most part of impurities are associated to Fe, Ni, Cr, Cu and Mn,probably forming oxides. Finally, from the comparative analysis made between the diversity of plants studied, we can conclude that their different operating conditions have an extremely important influence in the performance of the catalytic and recovering systems used.

After introducing fundamentals of catalysis with noble metal surfaces especially Pt metal for CO oxidation and subsequent developments on nano-crystalline Pt metals supported on oxide supports, an idea of Pt ion in reducible oxide supports acting as adsorption sites is proposed in chapter 1. Idea of red-ox cycling of an ion in an oxide matrix is presented taking Cu ion in YBa2Cu3O7 as an example. Noble metal ions in reducible oxides such as CeO2 or TiO2 acting as adsorption sites and hence a red-ox catalyst was arrived at from chemical considerations. Among several reducible oxide supports, TiO2 was chosen from crystal structure and electronic structure considerations. A good redox catalyst for auto exhaust and related applications should have high oxygen storage capacity (OSC). Any new material that can work as a redox catalyst should be tested for its OSC. Therefore we designed and fabricated a temperature programmed reduction by hydrogen (H2¬TPR) system to measure OSC. This is presented in chapter 2. We have synthesized a number of oxides by solution combustion method. Structures were determined by powder XRD and Rietveld refinement methods. Fe2O3, Fe2-xPdxO3-δ, Cu1-xMnAl1+xO4, LaCoO3, LaCo1-xPdxO3-δ, CeO2, Ce1¬xPdxO2-δ, TiO2, Ti1-xPdxO2-δ and many other oxide systems were synthesized and their structures were determined. OSC of these systems were determined employing the H2/TPR system. TPR studies were carried out for several redox cycles in each case. Except Pd ion substituted CeO2 and TiO2 other oxide systems decomposed during redox cycling. Pd ion substituted TiO2 gave highest OSC and also it was stable paving way to choose this system for further study. In chapter 3, we have described lattice oxygen of TiO2 activation by the substitution of Pd ion in its lattice. Ti1-xPdxO2-x (x = 0.01 to 0.03) have been synthesized by solution combustion method crystallizing in anatase TiO2 structure. Pd is in +2 oxidation state and Ti is in +4 oxidation state in the catalyst as seen by XPS. Pd is more ionic in TiO2 lattice compared to Pd in PdO. Oxygen storage capacity defined by ‘amount of oxygen that is used reversibly to oxidize CO’ is as high as 5100 μmol/g of Ti0.97Pd0.03O1.97. Oxygen is extracted by CO to CO2 in absence of feed oxygen even at room temperature. Rate of CO oxidation is 2.75 μmol.g-1.s-1 at 60 0C over Ti0.97Pd0.03O1.97 and C2H2 gets oxidized to CO2 and H2O at room temperature. Catalyst is not poisoned on long time operation of the reactor. Such high catalytic activity is due to activated lattice oxygen created by the substitution of Pd ion as seen from first-principles density functional theory (DFT) calculations with 96 atom supercells of Ti32O64, Ti31Pd1O63, Ti30Pd2O62 and Ti29Pd3O61. The compounds crystallize in anatase TiO2 structure with Pd2+ ion in nearly square planar geometry and TiO6 octahedra are distorted by the creation of weakly bound oxygens. Structural analysis of Ti31Pd1O63 which is close to 3% Pd ion substituted TiO2 shows that bond valence of oxygens associated with both Ti and Pd ions in the lattice is 1.87. A low bond valence of oxygen is characteristic of weak oxygen in the lattice compared to oxygens with bond valence 2 and above in the same lattice. Thus, the exact positions of activated oxygens have been identified in the lattice from DFT calculations. Pt has two stable valencies: +2 and +4. Ti ion in TiO2 is in +4 state. Is it possible to substitute Pt exclusively in +2 or +4 state in TiO2? Implications are that Pt in +2 will have oxide ion vacancies and Pt in +4 states will not have oxide ion vacancies. Indeed we could synthesize Pt ion substituted TiO2 with Pt in +2 and +4 states by solution combustion method. In chapter 4, we have shown the positive role of an oxide ion vacancy in the catalytic reaction. Ti0.97Pt2+0.03O1.97 and Ti0.97Pt4+0.03O2 have been synthesized by solution combustion method using alanine and glycine as the fuels respectively. Both are crystallizing in anatase TiO2 structure with 15 nm average crystallite size. X-ray photoelectron spectroscopy (XPS) confirmed Pt ions are only +2 state in Ti0.97Pt0.03O1.97 (alanine) and only in +4 state in Ti0.97Pt0.03O2 (glycine). CO oxidation rate with Ti0.97Pt2+0.03O1.97 is over 10 times higher compared to Ti0.97Pt4+0.03O2. The large shift in 100 % hydrocarbon oxidation to lower temperature was observed by Pt2+ ion substituted TiO2 from that by Pt4+ ion substituted TiO2. After reoxidation of the reduced compound by H2 as well as CO, Pt ions are stabilized in mixed valences, +2 and +4 states. The role of oxide ion vacancy in enhancing catalytic activity has been demonstrated by carrying out the CO oxidation and H2 + O2 recombination reaction in presence and in absence of O2. There is no deactivation of the catalyst by long time CO to CO2 catalytic reaction. We analyzed the activated lattice oxygens upon substitution of Pt2+ ion and Pt4+ ion in TiO2, using first-principles density functional theory (DFT) calculations with supercells Ti31Pt1O63, Ti30Pt2O62, Ti29Pt3O61 for Pt2+ ion substitution in TiO2 and Ti31Pt1O64, Ti30Pt2O62, Ti29Pt3O61 for Pt4+ ion substitution in TiO2. We find that the local structure of Pt2+ ion has a distorted square planar geometry and that of Pt4+ ion has an octahedral geometry similar to Ti4+ ion in pure TiO2. The change in coordination of Pt2+ ion gives rise to weakly bonded oxygens and these oxygens are responsible in high rates of catalytic reaction. Thus, the high catalytic activity results from synergistic roles of oxide ion vacancy and weakly bonded lattice oxygen. In chapter 5, we have shown high rates of H2 + O2 recombination reaction by Ti0.97Pd0.03O1.97 catalyst coated on honeycomb monolith made up of cordierite material. This catalyst was coated on γ¬Al2O3 coated monolith by solution combustion method using dip-dry-burn process. This is a modified conventional method to coat catalysts on honeycombs. Formation of Ti0.97Pd0.03O1.97 catalyst on monolith was confirmed by XRD. Form the XPS spectra of Pd(3d) core level in Ti1-xPdxO2-δ, Pd ion is the formed to be +2 state. Ti0.97Pd0.03O1.97 showed high rates of H2 + O2 recombination compared to 2 at % Pd(metal)/γ-Al2O3, Ce0.98Pd0.02O2-δ, Ce0.98Pt0.02O2-δ, Ce0.73Zr0.25Pd0.02O2-δ and Ti0.98Pd0.02O1.98. Activation energy of H2 + O2 recombination reaction over Ti0.97Pd0.03O1.97 is 7.8 kcal/mole. Rates of reaction over Ti0.97Pd0.03O1.97 are in the range of 10 – 20 μmol/g/s at 60 0C and 4174 h-1 space velocity. Rate is orders of magnitude higher compared to noble metal catalysts. From the industrial point of view, solvent-free hydrogenation of aromatic nitro compounds to amines at nearly 1 bar pressure is an important process. In chapter 6, we showed that Ti0.97Pd0.03O1.97 is a good –nitro to –amine conversion catalyst under solvent-free condition at 1.2 – 1.3 bar H2 pressure. Nitrobenzene, p-nitrotoluene and 2-chloro-4-nitrotoluene are taken for the catalytic reduction reaction. The amine products were analyzed by gas chromatography and mass spectrometry (GCMS). Further, confirmation of compounds was done by FTIR, 1H NMR and 13C NMR. In presence of alcohol as solvent, 100% conversion of aromatic nitro compounds to amines took place at higher temperature and it required more times. In n-butanol solvent, 100% conversion of nitrobenzene and p-nitrotoluene occurred within 10 h and 12 h at 105 °C respectively. We have compared solvent-free reduction of p-nitrotoluene over different catalysts at 90 °C. Catalytic activity for reduction of p¬nitrotoluene over Ti0.97Pd0.03O1.97 is much higher than that reaction over 3 atom % Pd on TiO2 and Pd metal. Turnover frequencies (TOF) for nitrobenzene and 2-chloro-4-nitrotoluene conversion are 217 and 20 over Ti0.97Pd0.03O1.97 respectively. With increase of temperature, TOF of aromatic nitro compound reduction is also increased. We have compared the solvent-free reduction of aromatic nitro compound over Ti0.97Pd0.03O1.97 with others in the literature. Upto 3 cycles of reduction reaction, there was no degradation of Ti0.97Pd0.03O1.97 catalyst and stability of catalyst structure was analyzed by XRD, XPS and TEM images. Catalyst is stable under reaction condition and the structure is retained with Pd in +2 state. Finally, we have proposed the mechanism of -nitro group reduction reaction based on the structure of Ti0.97Pd0.03O1.97. Instead of handling nano-crystalline materials we proceeded with coating our catalysts on cordierite honeycombs. In chapter 7, we have shown high catalytic activity towards Heck reaction over Ce0.98Pd0.02O2-δ and Ti0.97Pd0.03O1.97 coated on cordierite monolith. XRD patterns of Ce0.98Pd0.02O2¬δ coated on cordierite monolith were indexed to fluorite structure. Heck reaction of aryl halide with olefins over Ce0.98Pd0.02O2-δ and Ti0.97Pd0.03O1.97 coated on cordierite monolith were carried out at 120 °C. The products were first analyzed by GCMS and for the confirmation of compounds, we have recorded 1H NMR and 13C NMR. Heck reaction was carried out with different solvents and different bases for choosing the good base and a solvent. Hence, we have chosen K2CO3 as base and N,N¬dimethylformamide (DMF) as solvent. We have compared the rates of Heck reactions over these two catalysts and Ti0.97Pd0.03O1.97 catalyst showed much higher catalytic activity than Ce0.98Pd0.02O2-δ. With increase of temperature from 65 °C to 120 °C, the catalytic activity of Ti0.97Pd0.03O1.97 on Heck reaction is also increased. The catalyst was reused for next Heck reaction without significant loss of activity. A mechanism for Heck reaction of aryl halide with alkyl acrylate has been proposed based on the structure of Ti0.97Pd0.03O1.97. In chapter 8, we have provided a critical review of the work presented in the thesis. Critical issues such as noble metal ion doping in TiO2 vs noble metal ion substitution, difficulty of proving the substitution of low % noble metal ion in TiO2, need for better experimental methods to study noble metal ion in oxide matrix have been discussed. Finally, conclusions of the thesis are presented.

The diploma thesis is divided into four main parts. The first part deals with the issue of waste management and its energy utilization in waste incineration. Processed harmful substances produced by incineration as well as emission limits. It deals with the types of catalytic carriers, their description, production and more detailed processing of ceramic foam VUKOPOR. The second part is devoted to technologies utilizing catalytic processes and a more detailed specification of the process. In the third part there is processed the calculation methods for pressure losses for individual types of carriers. Fourth, the most extensive part describes the INTEQII experimental device, its technology and construction, as well as the principle of the practical part, measuring of the pressure losses of carriers. It includes the evaluation of pressure losses in separate categories of carriers, such as the bed, HoneyComb and VUKOPOR ceramic foam. Subsequently, a comparison of the pressure losses of all carriers is made relative to the reference size of 1 m. The impact of bonding of VUKOPOR foam samples on the size of pressure losses is discussed. At the end of this section, the suitability of calculation methods for individual carriers is evaluated, depending on the experimental pressure loss data.