At present, the issue of occurrence of female sex hormones, estrogens and progestogens, in aquatic ecosystems is often discussed by experts and the general public. These substances of steroid structure can be difficult to remove completely by conventional wastewater and drinking water treatment technologies. In given context advanced oxidation processes based on in situ generation of highly reactive hydroxyl radicals can be a suitable technique. This thesis deals with the study of kinetics and degradation products of photocatalytic decomposition of seven female sex hormones (estrone, -estradiol, estriol, ethinylestradiol, diethylstilbestrol, progesterone and norethindrone). Experiments were conducted in a laboratory glass reactor, which was equipped with an energy efficient UV-A LED light source (365 nm emission wavelength) and an immobilised photocatalyst in a form of TiO2 five-layer film deposited on glass. Model samples of water with the initial hormone concentration of 1 mg·L-1 were used and the degradation process was monitored by an HPLC-MS method. In the given system all compounds of interest except estriol had very significant tendency to be adsorb. In the case of estriol the formal rate constant of photocatalytic decomposition was determined based on the Langmuir-Hinshelwood model for two different initial concentrations, 0.5527 hour-1 (1 mg·L-1) and 0.1929 hour-1 (5 mg·L-1), and by comparison of these values it was found that the higher degraded compound concentration, the slower decomposition (fivefold increase of the initial concentration resulted in the constant decrease to almost one-third). Moreover nine degradation products of estriol photocatalytic decomposition were recorded and their structure was designed based on mass spectra. In the second thematic part of the thesis attention was paid to development of a SPE-HPLC-MS method for simultaneous determination of female sex hormones in water ecosystems, with emphasis on an extraction part optimization. The final samples treatment process included besides extraction with Supel™ Select HLB 200 mg SPE cartridges also mechanical impurities removal, hormones extraction from solids trapped on filtration material, sample acidification and extract purification with Supelclean™ ENVI-Florisil® cartridges. Optimised method was used for determination of female sex hormones in two Brno rivers, Svitava and Svratka. In the most cases the concentration was below the detection or quantification limit.

The photocatalytic wastewater treatment facility presented in this thesis is a promising economic green technology that can degrade wastewater’s organic and ammonia pollutants, which produce environmentally sensitive products like CO2, H2O, Nitrates, etc. that can be captured and used in many biological and engineering ways. Previous advances used for this research was determining the importance of cleaning the photocatalytic nanocrystals, Fe-TiO2, as one of the revolutionary improvements that expose and maximizes the active surface of the photocatalytic nanocrystals to the pollutants enabling the strong oxidants produced by the absorption of a photon, excitation of an electron and positive hole to produce oxidants on the surface of the nanocrystals. The oxidants indiscriminately produce CO2 and H2O from living and non-living organic matter to obtain near ~100% clean water. This research focused on taking the next steps in the development of a wastewater cleaning facility tested in our laboratory. An important step involved coating Fe-TiO2 crystals onto flexible, strong, fiber-glass cloth using a sol-gel processing method. Success was found in this research by applying the coated fiberglass cloth into a photoreactor aimed to clean a large amount of water rather than the laboratory scale. / Graduate

La photocatalyse laisse entrevoir un large champ d’applications dans de nombreux domaines parmi lesquels figurent principalement ceux du traitement et de la purification de l’eau et de l’air. Ceci constitue une des raisons pour lesquelles les études fondamentales des processus de dégradation des molécules organiques à la surface des photocatalyseurs concernent le plus souvent les phases liquides et gazeuses. Les développements plus récents des applications de la photocatalyse dans le domaine des surfaces autonettoyantes ont soulevé des problématiques fondamentales concernant les mécanismes de dégradation photocatalytique de composés solides tels que les suies et les acides gras. Ces problématiques restent encore peu abordées dans la littérature malgré les enjeux majeurs en terme environnemental et méritent donc des travaux de recherche plus approfondis. Cette thèse porte sur l’étude des modes de dégradation photocatalytique de dépôts solides d’acide stéarique (AS) sur des couches minces de dioxyde de titane. Dans ce travail, des approches expérimentales originales basées sur la microscopie optique sont mises en œuvre pour suivre la dégradation photocatalytique de ces dépôts d’AS à l’échelle microscopique sous exposition à la lumière ultraviolette. Les dépôts d’AS se présentent sous forme d’îlots microscopiques présentant une distribution de taille et de forme. Sur la base d’un nouveau modèle cinétique que nous proposons, le lien existant entre la vitesse de dégradation photocatalytique du dépôt et la distribution de taille initiale de la population d’îlots est mis en évidence. Le modèle cinétique développé permet de rationaliser nos résultats et de concilier d’autres résultats, jusqu’alors contradictoires, de la littérature. Ce travail propose en outre une étude originale sur la dégradation photocatalytique de microcristaux d’AS déposés sur des couches minces de TiO2 microstructurées qui a permis d’appréhender le rôle des radicaux libres dans le processus de dégradation photocatalytique. La démarche expérimentale est basée sur le lien étroit existant entre l’orientation des molécules, inhérente à la structure propre des microcristaux, et les directions des plans cristallographiques {hkl}. Ainsi, nous mettons en évidence une dépendance en {hkl} des vitesses de dégradation des microcristaux qui est justifiée à l’échelle moléculaire par l’affinité des radicaux pour les terminaisons chimiques exposées selon ces plans cristallographiques / Photocatalysis is widely used in a variety of applications in water and air purification. For those reasons, fundamentals research on the photocatalytical degradation processes of organic compounds on photocatalysts surfaces concern in most cases liquid and gaseous phases. The more recent development of self-cleaning surfaces has raised several issues concerning the mechanisms of photocatalytic degradation of solid deposits such as soot or fatty acids. These issues remain little addressed in the literature and therefore deserve further attention. This thesis work deals with the study of the photocatalytical degradation modes of solid deposits of stearic acid (SA) on the surface of titanium dioxide thin films. In this work, an original experimental approach based on the use of optical microscopy is implemented to monitor, on a microscopic scale, the SA deposits as a function of UV light exposure. Viewed under microscope, the SA deposits appear as microscopic islands presenting size and form distribution. On the basis of a new kinetic model we propose, the existing relationships between the degradation rate of the deposit and the initial size distribution of the islands population is demonstrated. The proposed kinetic model rationalizes our experimental results as well as several others from the literature. Additionally, an original study on the degradation of SA microcrystals, grown on microstructured TiO2 thin films, provides insight into the role of the photogenerated oxygenated radicals in the photocatalytical mechanisms. Furthermore, the anisotropy of the microcrystals structure is put in relation with that of the SA molecules orientations within the microcrystal. This explains the observed {hkl}-dependence of the degradation rate of the microcrystals

Les ressources en eau sont menacées par diverses formes de pollution et les procédés de traitement proposés sont souvent complexes avec des résultats qui ne sont pas toujours satisfaisants. Cette étude vise à développer un traitement, simple et peu coûteux pour réduire au maximum la présence dans l’eau des acides humiques (AH), un polluant organique. L’approche adoptée est la mise en place d’un procédé hybride combinant l’adsorption et la photocatalyse hétérogène réalisée avec le dioxyde de titane. La méthode d’adsorption a été réalisée d’une part avec du charbon actif et d’autre part avec trois argiles provenant de la Côte d’Ivoire. Le charbon actif a été préparé à partir des coques de coco selon une procédure assez simplifiée, sans additifs chimiques, dans le souci d’obtenir un adsorbant économique et écologique. Les trois argiles brutes (Dabou, Yamoussoukro et Katiola) ont chacune subi des opérations de purification pour obtenir des fractions pures. Des tests de caractérisation réalisés par diverses techniques (analyse élémentaire, DRX, adsorption d’azote, IR, etc.) ont été effectués sur les adsorbants obtenus. Les essais d’adsorption réalisés avec le charbon ont montré qu’aucune élimination des AH n’a été observé. La raison principale serait le manque de groupements fonctionnels sur la surface du charbon préparé. Les tests d’adsorption conduit avec les argiles ont montré que ces matériaux sont capables d’éliminer les AH. Les résultats ont révélé que l’argile la plus riche en kaolinite (celle de Yamoussoukro) a une capacité d’adsorption maximale largement supérieure (115 mg/g) par rapport aux autres (20 et 15 mg/g pour Dabou et Katiola respectivement). Cette différence trouve son explication dans la composition minéralogique et structurale de chacune des argiles. Les tests de photocatalyse menés ont montré une dégradation des macromolécules d’AH en des composés de plus petites tailles. La minéralisation de la matière organique a été observée avec une réduction du carbone organique total de l’ordre de 72 et 82 % respectivement aux pH 7 et 3. En mettant en série à pH 3, les deux procédés à savoir l’adsorption suivie de la photocatalyse, une réduction de 95% du carbone organique total des AH est obtenue. Le procédé hybride ainsi réalisé montre un avantage certain car il permet d’éliminer la quasi-totalité de la pollution organique initiale. / Water resources are threatened by various forms of pollution and the proposed treatment processes are often complex with results that are not always satisfactory. This study aims to develop a simple and inexpensive treatment to minimize the presence of humic acids (HA), an organic pollutant, in water. The approach adopted is the establishment of a hybrid process combining adsorption and heterogeneous photocatalysis performed with titanium dioxide. The adsorption method was carried out primary with activated carbon and secondary with three clays from Ivory Coast. Activated carbon was prepared from coconut shell by a simplified procedure, without chemical additives, in order to obtain an economic and ecological adsorbent. The three raw clays (Dabou, Yamoussoukro and Katiola) each underwent purification operations to obtain pure fractions. Characterization tests including various techniques (elemental analysis, XRD, nitrogen adsorption, IR, etc.) were carried out on the adsorbents obtained. Adsorption tests carried out with the coal showed that no elimination of HA was observed. The main reason is the lack of functional groups on the surface of the prepared coal. The adsorption tests conducted with the clays have shown that these materials are capable of removing HA. The results revealed that the clay richest in kaolinite (Yamoussoukro) has a much higher maximum adsorption capacity (115 mg/g) compared to the others (20 and 15 mg/g for Dabou and Katiola respectively). This difference found its explanation in the mineralogical and structural composition of each of the clays. Photocatalysis tests showed a degradation of the macromolecules of HA into smaller sizes compounds. The mineralization of the organic matter was observed with total organic carbon reduction rate equal to 72 and 82% at pH 7 and 3 respectively. By placing in series the two processes namely adsorption followed by photocatalysis, the removal percentage of HA obtained at pH 3, is about 95%. This hybrid process shows an advantage since it makes it possible to eliminate almost all of the initial organic pollution.

Industrial wastewater, such as the effluents from textile and garment companies, may contain toxic organic pollutants, which resist conventional wastewater treatment. Their complete and environmentally friendly degradation requires innovative technologies. Photocatalysis, an advanced oxidation process, can serve this purpose. Since 1972, when the photocatalytic activity of titanium dioxide was first noticed, photocatalysis has drawn the attention of scientists and engineers but it has not yet been widely applied in industrial practice. This is mainly related to the challenges of up-scaling from laboratory experiments to large production sites. The main goal of this thesis is to develop a concept of nanoparticle-based photocatalysis for the treatment of wastewater. Ideally, process parameters should be adjustable and process conditions should be well-defined. These constraints are prerequisite for establishing process models and comparing the photocatalytic efficiency of different photocatalysts or for different pollutants. More importantly, the configuration should be scalable, in order to cover a wide spectrum of applications. In response to these requirements, this thesis introduces a new reactor concept for photocatalytic wastewater treatment, which relies on finely dispersed photocatalysts as well as uniform and defined process conditions with regard to illumination and flow. The concept was realized in a photocatalytic setup with an illuminated flow reactor. The flow channel has a rectangular cross section and meanders in a plane exposed to two dimensional illumination. Crucial process parameters, e.g., volumetric flow rate and light intensity, can be adjusted in a defined manner. This facilitates the study on the photocatalytic degradation of different organic pollutants in the presence of various photocatalytic materials under arbitrary illumination. The thesis provides a comprehensive description of the operational procedures necessary to run photocatalytic reactions in the experimental setup. It includes three main steps: i) dispersion of photocatalysts, ii) equilibration with respect to pollutant adsorption and iii) accomplishing the photocatalytic reaction. Samples are collected in a mixing tank for online or offline analysis. The proceeding decrease in the concentration of organic pollutant is used to assess the activity of the photocatalytic materials. A particular focus lies on the first of these steps, the dispersion of photocatalysts, because it is ignored in most studies. Typically, photocatalysts are in an aggregated state. The thesis demonstrates that type, intensity and energy of dispersion exert a crucial influence on size and morphology of the photocatalyst particles and, thus, on their optical properties and, accordingly, macroscopic photocatalytic behavior. Apart from this, a proper dispersion is necessary to reduce speed of gravitational solid-liquid separation, at best, to prevent catalyst sedimentation and to avoid misleading results. The photocatalytic performance was intensively investigated for the color removal of a model dye substance, methylene blue. Commercial titanium dioxide nanoparticles, widely explored in literature, were used as a photocatalyst. Their characteristics (size, morphology, stability and optical properties) were determined. Photocatalytic experiments were carried out under UV irradiation. Influences of different factors, including the concentration of the photocatalyst, the concentration of the organic compounds, light intensity, optical pathlength and pH were examined. The degradation was quantified via the decrease of methylene blue concentration. This conversion is, however, an immediate result influenced by all process parameters, e.g., the volume, the light intensity, the optical pathlength. Hence, kinetic models on macroscopic and microscopic levels are established. Normalizations with respect to process conditions are proposed. The apparent reaction kinetics are traced back to volume- and intensity-related reaction rate constants, and the reaction rate constant at the illuminated surface of the reactor. Additionally, the model is modified to be used for time-variant UV intensities, as encountered for solar photocatalysis. These achievements allow for a comparison of the experimental results from different laboratories. Moreover, they are prerequisite for the translation of laboratory results into large scale plants. Selected case studies for further applications are introduced. The photocatalytic degradation of different organic molecules (one antibiotic and two commercial dyes) with different photocatalytic materials (commercial nanomaterials and self-synthesized magnetic particles) under artificial or natural light sources was performed. Additionally, photocatalysis was studied in a realistic application. Preliminary tests with dye solutions of a textile company in Danang, Vietnam, impressively showed the feasibility of wastewater treatment by means of photocatalysis. Based on the reported capacity of wastewater in the current treatment plant of the company, the necessary process parameters were assessed. The rough estimation showed that photocatalysis can improve the working ability of the current wastewater treatment plant. In conclusion, this thesis presents a concept for wastewater treatment by slurry photocatalysis. As the process conditions are adjustable and definable, the process can be ideally performed in laboratories for research purposes, where different materials need to be tested and the working volume can be lower than hundreds of milliliters. The photocatalytic configuration is expected to work with a capacity of hundreds of liters, although appropriate experimental evidences are reserved for further up-scaling studies.

M.Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Phenol, 2-chlorophenol (2-CP) is used in the manufacture of several chemical compounds including other chlorophenols, dyes, dentifrice and pesticides. The usage of these chemicals results in the discharge of 2-CP that is harmful to most biota in the environment. Therefore there is need to remove or degrade 2-CP from the environment, especially in water. This research focused on the synthesis, characterization and application of Ag doped semiconductor (TiO2, ZnO, and ZnS) nanoparticles for the removal of 2-CP from water. Sol-gel and co-precipitation methods were used to synthesize the nanoparticles with different Ag contents (1%, 3% and 5%). Silver metal was used as a doping agent due to its antibacterial activity and ability to improve the photocatalytic activity of the semiconductors for 2-CPdegradation under UV irradiation. Characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), Ultra-violet visible spectroscopy (UV-Vis) and photoluminescence spectra (PL) were used to characterize the structural, optical and physical properties of the nanoparticles, while Transmission electron microscopy (TEM) was used to characterize the surface of the nanoparticles. The XRD results confirmed the formation of anatase, wurtzite and blend phases of TiO2, ZnO and ZnS nanoparticles, respectively. The band gaps of the synthesized nanoparticles were 3.42 eV, 3.23 eV and 3.12 eV for TiO2, ZnO and ZnS nanoparticles respectively. The TEM images showed that all synthesized nanoparticles were uniform in shape. Photocatalytic degradation of 2-CP under UV irradiation confirmed that the semiconductor’s photocatalytic activities improved with the addition of Ag ions. The best removal percentage was obtained at doped Ag percentages of 5, 1 and 5 % using TiO2, ZnO and ZnS, respectively. In addition, the effects of various parameters affecting the photocatalytic degradation such as pH, initial concentrations of 2-CP and amount of catalyst (Ag doped TiO2, ZnO and ZnS, respectively) loading were examined and optimized. At the different initial concentrations of 2-CP, namely, 8, 20 and 50 ppm, the highest degradation efficiency was obtained at pH of 10.5 and 5 mg of catalyst dosage. However a decrease in initial concentration of 2-CP showed an increase in the photocatalytic efficiency. The degradation percentage of 2-CP obtained with Ag doped TiO2; ZnO and ZnS nanoparticles were 74.74, 57.8 and 45.49 %, respectively. Doping of these materials with Ag enhanced their photocatalytic activity; thus, they have the potential of degrading phenolic compounds, especially 2-chlorophenol, in water.

[ES] La presente tesis doctoral ha centrado la atención en la síntesis de nuevos materiales MOFs obtenidos por intercambio post-sintético de MOFs descritos anteriormente o por heterounión de MOFs estables que tienen estructura UiO66. Estos materiales se han aplicado como fotocatalizadores para la prometedora reacción de división completa del agua que pretende obtener H2 y O2 en forma estequiométrica a partir de agua en ausencia de agentes sacrificantes o nanopartículas metálicas. El nuevo material UiO66 (Zr/Ce/Ti) mostró resultados sorprendentes para la reacción general de división del agua en ambas condiciones de luz UV-Visible e irradiación solar. También se obtuvieron resultados interesantes en el caso del nucleo-corteza UiO66(Zr)-NH225@UiO66(Ce) que, en presencia de agua, cuando se irradió con luz ultravioleta y con luz solar, permitió obtener 550 𝝁 mol*g- 1 de H2 y 350 𝝁 mol*g-1 de H2 en 24 h respectivamente, en las mismas condiciones de trabajo definidas para UiO66(Zr/Ce/Ti). En este trabajo de tesis se presentó por primera vez la posibilidad de reducir 4-NP a través de una metodología tándem que involucra primero la producción de H2 a partir de agua en presencia de metanol, como agente de sacrificio, y UiO66(Zr)-NH2, como fotocatalizador, y la posterior reducción de 4-NP a 4-AP. Por otro lado, se ha demostrado que los materiales defectuosos con estructura de UiO66 pueden reducir selectivamente los dobles enlaces polarizados X=Y en presencia de gas H2. / [CA] La present tesi doctoral ha centrat l'atenció en la síntesi de nous materials MOFs obtinguts per intercanvi post-sintètic de MOFs descrits anteriorment o per heterounió de MOFs estables que tenen estructura UiO66. Estos materials s'han aplicat com fotocatalitzadors per a la prometedora reacció de divisió completa de l'aigua que pretén obtindre H2 i O2 en forma estequiomètrica a partir d'aigua en absència d'agents sacrificants o nanopartícules metàl·liques. El nou material UiO66 (Zr/Ce/Ti) va mostrar resultats sorprenents per a la reacció general de divisió de l'aigua en ambdós condicions de llum UV-Visible i irradiació solar. També es van obtindre resultats interessants en el cas del core-shell UiO66 (Zr) - NH225@UiO66 (Ce) que, en presència d'aigua, quan es va irradiar amb llum ultravioleta i amb llum solar, va permetre obtindre 550 𝝁 mol*g-1 de H2 i 350 𝝁 mol*g-1 de H2 en 24 h respectivament, en les mateixes condicions de treball definides per a UiO66 (Zr/Ce/Ti). En este treball de tesi es va presentar per primera vegada la possibilitat de reduir 4-nitrofenol a través d'una metodologia tàndem que involucra primer la producció de H2 a partir d'aigua en presència de metanol, com a agent de sacrifici, i UiO66 (Zr) -NH2, com fotocatalizador, i la posterior reducció de 4-NP a 4-AP. D'altra banda, s'ha demostrat que els materials defectuosos amb estructura d'UiO66 poden reduir selectivament els dobles enllaços polaritzats X=Y en presència de gas H2. / [EN] The present doctoral thesis has focused the attention on the synthesis of new MOFs materials obtained either by post-synthetic interchange of previously described MOFs or by heterojunction of stable MOFs having UiO66 structure. These materials have been applied as photocatalysts for the promising Overall Water Splitting reaction which claims to obtain H2 and O2 stoichiometrically starting from water in the absence of sacrificial agents or deposited metals nanoparticles. The new material UiO66 (Zr/Ce/Ti) showed surprising results in both UV- Visible light and sunlight irradiation conditions. Interesting results were also obtained in the case of the core-shell named UiO66(Zr)-NH225@UiO66(Ce) which, in the presence of water, when irradiated with both ultraviolet and solar light, allowed to obtain 550 𝝁 mol*g-1 of H2 and 350 𝝁 mol*g-1 of H2 in 24 h respectively, in the same working conditions defined for UiO66 (Zr/Ce/Ti). In this thesis was presented, for the first time, the possibility of reducing 4NP through a tandem methodology which, first, involves the production of H2 from water in the presence of methanol as a sacrificial agent and UiO66(Zr)-NH2 as a photo-catalyst, and subsequent the 4 NP reduction to 4 AP. On the other hand, it has been shown that defective materials with UiO66 structure can selectively reduce polarized X=Y double bonds in the presence of H2 gas. / Melillo, A. (2022). Metal-Organic Hybrid Materials with Catalytic and Photocatalytic Applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182744 / TESIS

Heterojunctions were generated between tungsten trioxide and tetraphenyl porphyrin with reduced graphene oxide or exfoliated graphite support for mineralisation of acid blue 25 dye under visible light radiation. Moreover, degradation of pharmaceuticals was conducted using p-n heterojunctions between WO3 and Co3O4 and a direct Z-scheme heterojunction between BiOI and Co3O4 prepared using in-situ method and solvothermal self-assembly method respectively. The synthesized materials were characterised using Raman, FTIR, SEM/EDS, TEM, XRD, TGA, BET, UV-Vis and PL techniques. UV-Vis, TOC and HPLC-QTOF-MS were used to study the degradation efficiency and pathway. Scavenger trapping experiments were conducted to propose the charge transfer mechanisms. The highest degradation efficiency (99 %) was achieved for the dye and the pharmaceuticals using visible light. The mineralisation ability of the fabricated nanomaterials was pH dependent with acidic conditions favouring the removal of the dye (pH 5) while alkaline conditions favoured the mineralisation of pharmaceuticals (pH 10 – 11). / Civil and Chemical Engineering

Ce travail a pour objet d’améliorer les performances d’un réacteur photocatalytique tubulaire de traitement des COVs, en le garnissant avec des supports structurés et imprégnés de TiO2. Grâce à un montage adapté, l’efficacité du réacteur est suivie en mesurant le taux de conversion du méthanol, choisi comme polluant modèle. Différentes géométries de support catalytique ont été fabriquées par stéréolithographie. Parmi toutes les géométries testées, la structure alvéolaire, constituée de canaux verticaux pour le passage du fluide et de canaux horizontaux pour le passage de la lumière, permet une efficacité optimale du réacteur. La modélisation du réacteur, tenant compte de la distribution de la lumière dans le support, montre que le transfert de matière est limitant lorsque le diamètre des canaux est plus petit que 4 mm. En revanche, lorsque le diamètre des canaux est supérieur à 5 mm, le manque d'efficacité est dû à une diminution de l'absorption de la lumière incidente. / The aim of the work is to improve the efficiency of a photocatalytic tubular reactor for VOCs abatement, while loading it with structured catalytic supports impregnated of TiO2.Thanks to a photocatalytic set-up , the efficiency of the reactor is followed by measuring the conversion rate of a model pollutant: methanol. Different geometries of support have been made by stereolithography. Among all tested geometries, the alveolar structure, composed of vertical channels for light penetration, and horizontal channels for the circulation of the gas flow, leads to an optimal degradation of the pollutant. The modelling of the reactor, taking into account the light distribution, shows that the mass transfer is limiting when the diameter of the channels is smaller than 4 mm. On the other hand, when the diameter of the channels is bigger than 5 mm, the lack of efficiency is due to a reduction of the absorption of the incident light by the catalytic surface.

Le rôle de WO3 et de Fe2O3 dans l’amélioration de l'activité photocatalytique des dépôts de TiO2 a été étudié, à travers la dégradation de l'acide salicylique avec deux sources de lumière : UV et visible.Différentes procédures de couplage de semi-conducteurs ont été entreprises (imprégnation humide / mélange de semi-conducteurs à l'état solide / sol gel). Aussi différents substrats ont été testés (verre ordinaire, ITO).La spectrophotométrie UV-Visible (sans / avec sphère intégratrice), la diffraction des rayons X, la microscopie électronique à balayage et la caractérisation électrochimique ont été réalisées afin de mieux comprendre le comportement et le rôle des semi-conducteurs chargés.Des résultats prometteurs ont été trouvés pour les photocatalyseurs préparés par imprégnation humide et par mélange solide (addition de WO3): le gap d’énergie a diminué, l'activité sous la lumière visible a augmenté en conséquence (2,5% molaire de WO3) pour le premier cas. Une amélioration de 30% sous UV (0,5% WO3) a été atteinte pour le deuxième. La méthode Sol gel améliore le recouvrement sur le substrat de verre, elle semble être appropriée pour assurer un bon contact entre les semi-conducteurs et atteindre l’effet désiré : la séparation de charges. Le photocourant a été nettement augmenté avec l’addition de 4% de WO3 (substrat ITO), en cohérence avec le potentiel de circuit ouvert diminué. Cela confirme le rôle positif de WO3 dans la séparation de charges.Les dépôts Fe2O3-TiO2 préparés par imprégnation humide présentent une activité supérieure avec la lampe blanche comparant à la lampe UV (de 1 à 2% molaire de Fe2O3), l’effet positif de l’introduction du fer a également été observé avec la méthode sol gel. Le Fer sous sa forme ionique peut jouer un rôle positif dans le piégeage de charges, mais il peut former des phases allotropiques qui peuvent être des centres de recombinaison / The role of WO3 and Fe2O3 in enhancing the photocatalytic activity of TiO2 deposits has been investigated through the oxidation of salicylic acid using UV and vis-light irradiation. Different procedures of semiconductor loading (wet impregnation/mixing semiconductors in solid form/sol gel) and deposition were undertaken. Also different substrates were tested (ordinary glass, ITO).UV-Vis spectrophotometry (without/with Integrating sphere), X-ray powder diffraction, scanning electron microscopy and electrochemical characterization were done in order to better understand the behavior and the effective role of loaded semiconductors.Promising results were found for catalysts prepared by wet impregnation and mixing in solid form methods (WO3-loading): the bang gap energy decreased, activity under visible light increased consequently (at 2.5 % molar -WO3) for the first case. 30% improvement under UV (0.5 % -WO3) was reached for the second. Sol gel method enhances coverage on the glass substrate, it seems to be an appropriate method to ensure good contact between semiconductors and reach the charge separation desired effect. Enhanced photocurrent on the ITO substrate confirms the positive role of WO3 in charge separation, in coherence with open circuit potential which was found to be reduced with 4 % WO3 loading. Fe2O3-TiO2 coatings prepared by wet impregnation exhibit higher activity with white lamp comparing to UV lamp (loading from 1 to 2 % Fe2O3), also positive effect of iron introduction was observed with sol gel method. Iron under his ionic form can play positive role in trapping charge, but it can form allotropic phases which can be centers of recombination.Key words: TiO2; WO3; Fe2O3; band gap; salicylic acid; photocatalysis; sol gel