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Gas phase dehydration of glycerol formerly in aqueous solution to acrolein was studied over iron MFI zeolites prepared by post-synthesis isomorphous substitution with different iron contents, Si/Al and substitution ratios. High Si/Al (60) ratios led to high conversion in presence of air and the insertion of iron in the zeolite framework greatly improved the catalytic performances by altering the amount and the nature of the coke components reducing dramatically the deactivation. Over the most efficient sample, acrolein yield reached a stabilized value of 68% with an excellent selectivity (80%), which ranked this catalyst among the best for the selective conversion of crude glycerol.

Fe-MFI zeolites are very promising materials for the oxidehydration of glycerol. This work shows that preparation procedure influences product selectivity. Hydrothermal synthesis is more selective to acrylic acid thanks to the Fe(+III) tetrahedral species in framework position. Conversely, post-synthesis treatment in a fluoride medium generates Fe(+II) Ox clusters in extra-framework position that increases acrolein selectivity. The reduction of the crystalline size of iron MFI to a nanoscale leads to a highly active, selective and stable catalyst with a stabilized glycerol (40 wt% in water) conversion of 90% and acrolein selectivity of 87%.

International audience; The preparation by post-synthesis isomorphous substitution of Fe.sub.X-BEA-Y in one step was investigated for the oxidehydration of pure glycerol. TPR and DR UV-vis highlighted the presence of Fe.sup.(+III) species in the framework of zeolites. Iron allows the activation of the catalyst by the reduction by glycerol of part of Fe.sup.(+III) into Fe.sup.(+II) species, which stabilizes the glycerol conversion. Total glycerol conversion is obtained with 4wt% of iron and acrylic acid yield reaches 23% over this catalyst. The Fe.sup.(+III) tetrahedral species are thought to be the main active redox sites for the formation of acrylic acid.

International audience; The catalytic oxidation of dichloromethane (DCM, 1000 ppm) in wet air was carried out in a fixed bed reactor over a range of Pt/γ-Al2O3 catalysts. The dichloromethane oxidation occurs following a bifunctional mechanism. DCM is disproportionated over γ-Al2O3 into a 1/1/3molar mixture of CO, CH3Cl, and HCl; the DCM transformation is followed by CH3Cl and CO oxidation into CO2. A mechanism of DCM disproportionation is proposed involving, as intermediates, formate species as well as alumina hydroxyl groups formed by water adsorption

International audience; The aim of this work was to evaluate the possible synergy in hybrid catalysts composed of the two types of solids and to study their performances in the catalytic combustion of isopropanol. Several catalysts, based on cerium oxide and zeolites, for the catalytic oxidation of volatile organic compounds (VOCs), especially isopropanol, were tested. This study was assessed by determining the catalysts activity, selectivity and deactivation at various temperatures after 5 h of reaction. An important part of the work was the preparation and characterization of the catalysts, in particular the study of oxygen storage and mobility. Hybrid catalysts exhibit a synergy effect in terms of oxygen storage capacity and oxygen isotopic exchange. However, even if a synergy effect is also observed in catalytic oxidation over some samples, the oxygen mobility does not ensure better results in isopropanol combustion. (C) 2011 Elsevier B.V. All rights reserved.

The catalytic combustion of 1-methylnaphthalene (1-MN), a PAH representative molecule, was carried out over USHY and 0.8%PtUSHY catalysts in presence of steam. These catalysts are able to transform low concentration of 1-MN into carbon dioxide at 300 °C over USHY catalyst and at 200 °C over PtUSHY, without by-products formation. The presence of platinum on the USHY increases the catalytic activity, hence the reaction rate. The influence of platinum content showed that 0.5% of platinum deposited on the zeolite was sufficient to oxidize 900 ppm of 1-MN at 300 °C. The influence of water content in the feed was investigated and several assumptions were put forth to explain our results. The carbon dioxide yield decreases in the 0–12% range of relative humidity (RH). When RH increases up to 12% the carbon dioxide yield increases. Over USHY catalyst and for low water content (RH 2 O dimer (neutral complex form) formation. Over PtUSHY catalysts, water adsorption over the PtO phase could be considered. For high water content (RH > 12%), water cluster formation via H 2 O dimer (ion-pair complex form) is proposed on both catalysts. This form of H 2 O dimer (ion-pair complex) could generate an acidity, which facilitates the formation of oxygenated compounds easily degradable into carbon dioxide.

Catalytic oxidation of isopropylbenzene (cumene, 210 ppm) in wet air was essentially investigated over basic NaX zeolite. Experiments were carried out in presence of water (11,000 ppm) and at a gas hourly space velocity (GHSV) of 18,000 h−1. Over NaX, the cumene showed a catalyst activation phenomenon during the reaction time. Indeed, after 175 min of reaction at 250 °C the conversion of cumene increases from 45% to 100% and the CO2 yield from 30% to 95% probably because of the formation of active species mainly localized at the cavities apertures of the basic zeolite. Peroxide or peroxy radicals were proposed to be these particular active species.

The catalytic oxidation of tetrachloroethylene (PCE), chosen as model for chlorinated hydrocarbons, was investigated over Pt/HY, Pt/NaY and Pt/NaX under humid conditions at a space velocity of 15,300 h −1 . PCE is selectively transformed into carbon dioxide (CO 2 ) and hydrochloric acid (HCl) over all catalysts studied in this work. 1.2%Pt/HY exhibits the highest activity with the complete conversion of PCE at 500 °C and undergoes no significant deactivation after 4 h of reaction. It was also highlighted in this work, that water vapour plays a preponderant role for PCE transformation and limits catalyst deactivation. On the other hand, platinum-exchanged sodic faujasites (Pt/NaFAU) are also active in PCE transformation but it appeared that 1%Pt/NaX underwent a high and rapid deactivation by the formation of sodium chloride (NaCl) clusters.

In this work, the removal of tetrachloroethylene (PCE) over faujasite-type zeolites exchanged with various cations was investigated under static and dynamic conditions. The nature of the non-framework cation appeared as a predominant parameter, in terms of adsorbate−adsorbent interactions as well as adsorbent micropore volume. Indeed, a molecular simulation has highlighted the interaction between cations and Cl atoms. Moreover, it was observed that the nature of the cation strongly influenced the adsorbent behavior in the PCE removal process. Cationic zeolites appeared as efficient materials for the removal of PCE with good adsorption capacities, in particular, the sodium-exchanged X and Y zeolites. The presence of steam in the gas feed was determined to have a strong negative effect on the performance of the cationic zeolites. However, the addition of 3A sieve in a double bed with NaY zeolite appeared to be a good system. The complete regeneration of the system was obtained at relatively low temperature ...

Catalytic oxidation of monochlorobenzene (667 ppm) in wet air was investigated over PtHFAU(5) catalysts, differing by their Pt content (from 0 to 1.1 wt.%), their Pt dispersion (for identical Pt content) and the electronic state of Pt. PtHFAU(5) catalysts show a higher activity compared to more conventional PtAl2O3 and PtSiO2 samples. For a given temperature, chlorobenzene oxidation over PtHFAU(5) is independent of the platinum particles size. On the other hand, a plateau in activity is reached from 0.4 to 0.6% Pt. Amount of polychlorinated benzenes (PhCl2+) were produced in the order PtAl2O3 > PtSiO2 > PtHFAU(5). The formation of these compounds, especially PhCl2, over PtHFAU(5) was function on the Pt content (PhCl2 isomers appear only from 0.6% PtHFAU), and of the electronic state of Pt. Thus PhCl2, were mainly found over reduced Pt0 particles certainly through a chlorination of platinum (formation of PtClx species). A reaction scheme for the PhCl2 formation was proposed.

Catalytic oxidation of dichloromethane (DCM, 1000 ppm) in wet air was investigated over PtHFAU catalysts differing by their Pt content (from 0 to 0.87 wt.%), the Si/Al ratio being constant and equal to 5. For a given temperature, the rate of DCM transformation is independent of the platinum particles size and of the platinum content. On the other hand, DCM oxidation into CO2 occurs through a bifunctional mechanism: DCM was firstly hydrolysed into HCl and formaldehyde on the Bronsted acid sites of the support. Afterwards, formaldehyde was oxidised into CO2 and H2O on the platinum sites. A reaction scheme was proposed to explain the complete oxidation of DCM over PtHFAU catalysts.

The catalytic oxidation of dichloromethane (DCM, 1000 ppm) in wet air was carried out in a fixed bed reactor over NaY, pure, exchanged with 0.5 wt% Pt or added with 0.4 wt% PtSiO 2 . At low temperatures (⩽250 °C) DCM is selectively hydrolyzed into 2/1 molar mixture of HCl and formaldehyde ; at higher temperatures with Pt catalysts, DCM hydrolysis is followed by formaldehyde oxidation into CO 2 and water, which suggests a bifunctional scheme. DCM transformation was investigated over pure NaY, the zeolite samples being characterized after reaction by adsorption of nitrogen, of pyridine followed by IR spectroscopy, and of DCM followed by microcalorimetry. During the first 15 min of reaction, a significant decrease in conversion could be observed as well as large changes in the NaY properties: disappearance of the strongest sites for DCM adsorption, creation of acidic bridging OH groups, etc., suggesting a stoichiometric reaction of DCM with NaY. Afterward, the process became catalytic with no more change in DCM conversion and in the physicochemical properties of the zeolite. A mechanism of DCM hydrolysis is proposed involving as intermediates chloromethoxy, hydroxymethoxy, and NaCl species as well as the OH groups created on the NaY zeolite.

A high-throughput vapor-phase catalytic experimentation unit with 15 parallel microreactors and fast, on-line GC product analysis was built. The 15 open tubular microreactors were mounted in a single furnace and fed with a common gas stream. Decane hydroisomerization experiments were conducted on 35 mg quantities of reference platinum-loaded ultrastable Y zeolite particles at 200 °C, 4.5 bar, using a hydrogen/hydrocarbon molar ratio of 375/1 and contact times of 100–800 kg s/mol. The microreactor outlets were sampled sequentially. GC analysis of the C1C10 alkane product mixtures was achieved in 3.2 min with a multi-capillary column. The actual gas flow rates and contact times in the individual microreactors were derived from the GC FID signals after dilution of the reaction product stream with a calibrated hydrogen gas flow. The maximum temperature difference among the microreactors, measured in an empty reactor unit was ca. 6 °C at 200 °C. The conversion data were in excellent agreement with a kinetic model established for a conventional reactor. Fitting of the kinetic data obtained in the individual microreactors to the model confirmed the small temperature variations depending on the location of each microreactor in the catalyst furnace.

The competitive transformation of cyclopentanone and of two thiols (cyclopentanethiol and cyclohexanethiol) was carried out on a sulfided CoMo/Al2O3 catalyst at 220°C under atmospheric pressure in the presence of H2/H2S (90/10 vol.%). The results made it possible to explain the good selectivity in cyclopentanethiol obtained in the thioreduction of cyclopentanone. This is the consequence of the inhibition due to a competition to adsorption, of the thiol desulfurization into the corresponding olefin. The kinetic order with respect to cyclopentanone of the transformation of cyclohexanethiol into cyclohexene was found equal to −0.6.

The mechanism of the hydrodesulfurization of dibenzothiophene-type compounds involving their dihydroderivatives as intermediates was examined in the light of previous experimental results dealing with the effect of cobalt and nickel promoters on the selectivity of the reaction. It is suggested that the orientation of the hydrodesulfurization reaction regarding the so-called “direct desulfurization” or “hydrogenation” pathways depends on various factors: the distribution of the dihydrointermediates (two of them only among nine possible isomers can lead directly from dibenzothiophene to biphenyl); the availability of dissociated hydrogen on the catalytic centers on which they adsorb and the basicity of the sulfur anions associated to the catalytic centers.

Two series of sulfided Ni or Co promoted Mo/alumina catalysts, having different Ni or Co loadings, were characterized by their activities for the transformation of cyclopentanone into cyclopentanethiol (flow reactor, 220°C, atmospheric pressure) and for the hydrodesulfurization of dibenzothiophene (flow reactor, 340°C, 3 MPa hydrogen pressure). The addition of the promoter increased significantly the activity of the Mo/alumina catalyst for both reactions, up to a maximum obtained with the catalysts having a (promoter)/(promoter+Mo) molar ratio equal to 0.3–0.4. This increase in activity was due in part to an increase in the hydrogenating properties of the Mo/alumina catalyst. However, an additional modification of the catalyst (basic and nucleophilic properties) must be considered to account for the spectacular effect of the promoter on the rate of the dibenzothiophene direct desulfurization reaction.

International audience; The possibility to understand the phenomena of oxygen diffusion in the solids may be decisive to explain the role of framework oxygen atoms in a catalytic mechanism or in catalyst regeneration steps. In this work, two highly efficient characterization techniques have been associated: the O-17/O-16 isotopic exchange and the O-17 high field solid-state NMR spectroscopy. This combination leads to a powerful tool to investigate the interaction between gaseous dioxygen molecule and lattice oxygen atoms. Here, it permits to demonstrate the enhancement of the participation of zeolitic oxygen atoms in the exchange with the gas phase when ceria is simply mixed with NaX

Times Cited: 0 Article English Cited References Count: 70 749zn; Both Lewis and Bronsted basic properties of magnesium oxide (MgO) are, respectively, studied by adsorption of CO2 and methanol CH3OH. Various chemical synthesis of pure magnesium oxide (commercial, sol-gel and precipitation methods) are used. The influence of small amounts of alkaline (Na+ and Li+) and alkaline-earth (Ca2+) cations is also reported. The amount and the strength of Lewis and Bronsted basic sites are determined by heat flow microcalorimetry. As observed with doped MgO samples, the amount of basic sites is increased but the strength of these sites remains the same. The observed strength of Bronsted sites is generally lower than the Lewis ones. These measurements reveal trends based on the synthesis process that can have an important impact on these basic properties. (C) 2011 Elsevier B.V. All rights reserved.

International audience; Catalytic oxidation of isopropanol and o-xylene alone as well as in mixture was investigated over basic NaX zeolite. Experiments were carried out in wet air (11,000 ppm of water) and at a high gas hourly space velocity (GHSV) of 18,000 h(-1). Results show an inhibiting effect of the o-xylene on the isopropanol destruction whereas the isopropanol has no effect on the o-xylene destruction. Adsorption experiments as well as molecular modelling seem to demonstrate that this inhibiting effect of o-xylene is due to the adsorption of this aromatic VOCs near the apertures of the NaX supercages limiting the access of isopropanol to the basic active sites of this zeolite. Furthermore, the concentration of o-xylene influences the formation of secondary products (propene, coke) resulting from the isopropanol transformation. (C) 2010 Elsevier B.V. All rights reserved

The catalytic combustion of benzofuran and of benzofuran/1,2-dichlorobenzene binary mixture over zeolite catalysts was investigated. The benzofuran is much easier to oxidize compared to chlorinated aromatic compounds and PtNaY is the most adapted catalyst for this oxidation reaction. Unfortunately, in the presence of the benzofuran/1,2-dichlorobenzene mixture, PtNaY catalyst deactivates and becomes less adapted for oxidation reaction than a catalyst based on acid zeolite like HY (Si/Al = 5). Thus, PtHY proved to be a promising catalyst for 1,2-dichlorobenzene mixture degradation. The presence of benzofuran in mixture clearly improves the conversion of chlorinated compound, decreases the production of chlorinated by-products and enhances the selectivity into CO2. The oxidation of benzofuran/1,2-dichlorobenzene mixture is also influenced by the platinum content deposited on zeolite, the activity of PtHY catalyst increasing linearly with the platinum level. Thus, at 350 °C, the 1.2% PtHY catalyst is able to completely oxidize the 1,2-dichlorobenzene in mixture into CO2 with production of a low amount of PhClx by-products. Deactivation has been studied on 1.2% PtHYcatalyst, catalyst initially deactivates during the first 24 h reaction. The main cause of this initial deactivation is certainly a Pt sintering leading to a collapse of the cristallinity of the zeolite. However, after 24 h reaction PtHY catalyst was stable and allows to oxidize 1,2-dichlorobenzene with a limited formation of polychlorobenzene by-products.

This study is focused on the adsorption of a chlorinated volatile organic compound, the tetrachloroethylene (PCE), on dealuminated faujasite type zeolites with framework Si/Al ratio between 5 and 100. PCE dynamic adsorption experiments with and without water vapour (relative humidity of, respectively, 50% and 0%) were carried out in a fixed bed reactor at 50 °C. Breakthrough curves were fitted by a model using the integral of a Gauss distribution. PCE adsorption capacities depend on the adsorbent microporous volume. However, in presence of water vapour, PCE adsorption is favoured on hydrophobic zeolites but also depends on the diffusional limitations inside the porous system. In order to have a better understanding of water molecules adsorption, isotherms were measured using thermogravimetric method at 25 °C. The presence of water vapour generally decreases PCE uptake but its influence decreases as the Si/Al ratio of the adsorbent increases. Experiments with various gases hourly space velocity (GHSV) and inlet PCE concentrations were also performed. PCE complete desorption was obtained on HFAU(Si/Al = 17) at 180 °C. This easy regeneration of the sample permitted adsorption/regeneration cycles maintaining good adsorption properties.

The catalytic oxidation of isopropanol and o-xylene alone and in mixture was investigated over basic zeolites (CsX and NaX) and an acidic zeolite (HY). For a given temperature, the conversion of VOCs mixture into CO2 increases with the basicity of the zeolite. Results show that VOCs are oxidized through a basic mechanism over NaX, and through an acidic mechanism over HY. Over HY, the presence of isopropanol increases the oxidation of o-xylene, probably because of the formation of isopropyldimethylbenzenes obtained via an acidic mechanism. The addition of platinum over zeolites increases the rate of the VOCs oxidation, this behavior being more pronounced over PtHY maybe because of a higher Pt dispersion.

The catalytic oxidation of 1,2-dichlorobenzene was investigated over NaYand NaX zeolites, loaded with chromiumthrough the action of a robust biosorption system consisting of a bacterial biofilm supported on the zeolites. The results of biosorption showed that the maximum metal removal efficiencywas 20%, in both systems based on NaYorNaX, starting fromsolutions with chromium(VI) concentrations ranging from 50 to 250 mgCr/L. The bacterial biofilm, Arthrobacter viscosus, supported on the zeolite reduces Cr(VI) to Cr(III). The Cr(III) is retained in the zeolite by ion exchange. The new catalysts were characterized by spectroscopic methods (FTIR ), chemical analyses (ICP-AES), surface analysis (XRD) and thermal analysis (TGA). The various techniques of characterization show that this biosorption process does not modify the morphology and structure of the FAUzeolites. These catalysts,Cr/FAU, prepared through this newprocedure present good activity and selectivity for dichlorobenzene oxidation in wet air at 350 ºC. The Cr50-Y was selected as the most active, selective and stable catalyst for oxidation of 1,2-dichlorobenzene in wet air., Departamento de Ciências da Terra of Universidade do Minho; Fundação para a Ciência e a Tecnologia (FCT) ; Agence de l’Environnement et de la Maîtrise de l’Energie (ADEME); Région Poitou-Charentes.

Catalytic oxidation of 1,2-dichlorobenzene (1,2-PhCl 2 ) (667 ppm) in wet air was investigated over protonic zeolites (HFAU, HBEA, HMFI, HMCM22 and ITQ2) and their corresponding Pt samples. Protonic zeolites are active to oxidize 1,2-PhCl 2 in the range of 350–400 °C. The presence of Bronsted acid sites on zeolite favors the degradation of 1,2-PhCl 2 . Furthermore, the presence of micropores through a confinement effect certainly participates to the increase of catalyst activity. Finally, addition of platinum increases activity of zeolites but also favors by-products formation such as polychlorinated compounds like 1,2,4-PhCl 3 isomers.

The catalytic oxidation of dichloromethane (DCM) was investigated over PtNaX and PtNaY catalysts with different amounts and dispersions of Pt under the following conditions: fixed bed reactor, 1000 ppm of DCM in wet air, space velocity of 20,000 h –1 , temperature between 220 and 450 °C. It is shown that Pt has only a limited effect on DCM conversion but causes a significant change in the product composition; the only role of Pt is to oxidise formaldehyde resulting from DCM hydrolysis on the zeolite support. DCM hydrolysis was carried out over a series of FAU zeolites: NaX, LiY, NaY, KY, CsY and USHY. The hydrolysis rate was shown to increase significantly with the zeolite basicity. A general reaction mechanism is proposed involving mainly the transformation of DCM species adsorbed on acido (H + , alcaline cation) basic (zeolite, framework oxygens) sites into chloromethoxy then hydroxymethoxy species. To cite this article: L. Pinard et al., C. R. Chimie 8 (2005).

Air pollution was considered responsible for 7 million premature deaths in 2015 and comes from two main sources: outdoor and indoor air. Indeed, the lack of air renewal in confined spaces such as houses, offices or schools leads to higher pollutant concentrations than in open spaces. Volatile organic compounds are considered to be one of the largest families of pollutants. Among them, formaldehyde, which causes irritation at low levels and has recently been classified as a carcinogenic 1B, can be found in significant amounts in confined spaces following combustion phenomena, from plastics, wooden furniture, cleaning products or insulating materials.Heterogeneous catalysis can be an effective way to remove these harmful molecules by transforming formaldehyde into carbon dioxide at the lowest temperature possible. In order to replace noble metals, whose activity is very high but whose cost and rarity are obstacles to their use, the performances of 3 families of materials were discussed during this work. At first, the use of zeolites of the H-ZSM5 type modified by post synthesis isomorphic substitution seemed to be an interesting solution due to the adsorbent properties of the parent material on the one hand and on the other hand thanks to the oxidative function provided by the presence of new elements such as cobalt, iron, manganese or even cerium. The modification of the parent zeolite led to a clear improvement in catalytic activity since the total conversion was achieved in the case of zeolites modified with manganese, iron and cerium from 300°C for the most active sample while the parent material allowed a conversion of only 70% at 500°C. However, the manganese sample stood out for its much higher activity than the other materials in the series. However, the catalytic activities observed were far from the performance observed on samples containing noble metals.A second part of this study concerned materials based on cerium oxides which also seemed to be good candidates for oxidation reactions due to their ability to store and remove oxygen. These materials, cerina-zirconia doped with copper, cobalt, iron or manganese, prepared by an epoxid sol-gel method, showed that the synthesis conditions used mainly led to the production of mixed non-homogeneous oxides. Catalytic tests have shown that the addition of a transition metal to ceria-zirconia materials can improve their catalytic activity. The most active material for the oxidation reaction of formaldehyde was copper-containing material. The main improvement was the selectivity of the reaction. Indeed, doping with these transition metals mainly leads to the formation of CO2 while forming formic acid and CO, but also to reduction product, methanol, which confirms one of the few studies on the subject in the litterature.Finally, previous studies having shown the existence of a synergistic effect in CuO-ZnO-Al2O3 materials for the hydrogenation reaction of CO2 to methanol, a more exploratory part was then dedicated to the study of these solids in the catalytic oxidation reaction of formaldehyde. It has been observed that materials containing copper oxide provide the best catalytic activities while avoiding the formation of undesirable reaction co-products. This study showed the high potential of these materials for the oxidation of formaldehyde with cheap, very abundant, active and highly CO2 selective metals, thus allowing to reduce indoor pollution.; La pollution de l’air fut considérée comme responsable de 7 millions de morts prématurées en 2015 et provient de deux origines principales : l’air extérieur ou intérieur. En effet, le manque de renouvellement d’air dans des espaces clos tels que les maisons, les bureaux, les écoles, ... conduit à des concentrations en polluants plus importantes que dans des espaces ouverts. Les composés organiques volatils sont considérés comme l’une des plus grandes familles de polluants. Parmi eux, le formaldéhyde, qui provoque des irritations à de faibles teneurs et qui est depuis peu classé comme produit cancérogène 1B, peut se retrouver en quantité non négligeable dans des espaces clos suite à des phénomènes de combustion, par relargage des plastiques, meubles en bois, produits d’entretien ou encore matériaux isolants.La catalyse hétérogène peut être un moyen efficace d’éliminer ces molécules nocives en transformant le formaldéhyde en dioxyde de carbone à la plus basse température possible. Dans le but de remplacer les métaux nobles, à l’activité très élevée mais dont le coût et la rareté sont des freins à leur utilisation, l’étude de 3 familles de matériaux a été abordée au cours de ce travail. Dans un premier temps, l’utilisation de zéolithes de type H-ZSM5 modifiée par substitution isomorphe post synthèse semblait être une solution intéressante de par les propriétés adsorbantes du matériau parent d’une part et d’autre part grâce à la fonction oxydante apportée par la présence de nouveaux éléments tels que le cobalt, le fer, le manganèse ou encore le cérium. La modification de la zéolithe mère a conduit à une amélioration nette de l’activité catalytique puisque la conversion totale a été atteinte dans le cas des zéolithes modifiées à l’aide du manganèse, du fer et du cérium dès 300°C pour l’échantillon le plus actif tandis que le matériau parent permettait d’obtenir une conversion de seulement 70 % à 500°C. L’échantillon au manganèse s’est toutefois démarqué par son activité bien plus importante que les autres matériaux de la série. Cependant, les activités catalytiques observées étaient bien loin des performances observées sur des échantillons contenant des métaux nobles.Un second volet de cette étude concernait les matériaux à base d’oxydes de cérium qui semblaient également être de bons candidats pour des réactions d’oxydation du fait de leur capacité à stocker et déstocker de l’oxygène. Ces matériaux, préparés par sol-gel par voie époxyde à base de cérine-zircone dopée par du cuivre, cobalt, fer ou manganèse ont montré que les conditions de synthèse utilisées conduisaient principalement à l’obtention de composés mixtes d’oxydes non homogènes. Les tests catalytiques ont montré que l’ajout d’un métal de transition à des matériaux de type cérine-zircone améliorait l’activité catalytique. Le matériau le plus actif pour la réaction d’oxydation du formaldéhyde était celui contenant du cuivre. La principale amélioration a résidé dans la sélectivité de la réaction. En effet, le dopage par ces métaux de transition conduit principalement à la formation de CO2 accompagné d’acide formique, de CO mais également d’un produit de réduction, le méthanol, conduisant à confirmer l’une des rares études présente sur le sujet dans la littérature.Enfin, des études antérieures ayant mis en évidence l’existence d’un effet de synergie dans des matériaux de type CuO-ZnO-Al2O3 pour la réaction d’hydrogénation du CO2 en méthanol, une partie plus exploratoire a alors été dédiée à l’étude de ces solides dans la réaction d’oxydation catalytique du formaldéhyde. Il a pu être observé que les matériaux contenant de l’oxyde de cuivre permettaient d’obtenir les meilleures activités catalytiques tout en évitant la formation de co-produits de réaction indésirables.Cette étude a montré le fort potentiel de ces matériaux pour l’oxydation du formaldéhyde avec des métaux peu chers et très abondants, actifs et très sélectifs en CO2, réduisant ainsi la pollution intérieure