Design of precursors and control of their assembly
The activity of axis 1 focuses on the design and custom synthesis of molecular and macromolecular precursors and their organization into supramolecular assemblies. It is based on the design and synthesis of organic, inorganic or hybrid precursors as well as precursors from bio-resources. The custom design of the basic bricks makes it possible to develop their assemblies through the control of the cooperative or competitive interactions involved. The control of interactions at interfaces, especially organic-inorganic, is the key to the production of hybrid and/or porous materials controlled by soft chemistry. The materials formed are characterized by advanced techniques for probing local or mesoscopic scale interactions, associated with multi-scale computational modeling studies (micro and mesoscopic). Inorganic precursors can be molecules, organometallic complexes, clusters or colloids; They include precursors of silica, metal oxides or mixed oxides. Organic entities can be sugars, polymers of natural origin: polysaccharides, tannins, alginates or chitosanes, but also polymers prepared to order with a control of architecture and functionality. In the case of Metal Organic Frameworks (MOFs), new organic (ligands) and inorganic (metal clusters) base bricks are developed. Hybrid and even bio-hybrid precursors (mimicking for example amino acids, collagen…) are also designed and synthesized.
The activities of axis 1 are also focused on the study of the interactions between these precursors and on the control of the formation of controlled supramolecular assemblies from the construction units. These studies are carried out using spectroscopic and radiation scattering techniques (light, neutrons, X-rays) coupled, where appropriate, with molecular modelling. The interactions between surfactants and polymers are characterized, with, depending on their nature (hydrophobic, electrostatic complexation, hydrogen bonds, etc.), particular attention paid to the influence on micellization of physico-chemical parameters (temperature, pH, ionic strength, etc.). The control of interactions allows a control of the properties (characteristic sizes, morphologies) of micellar assemblies which are used as structuring agents of porous and hybrid materials (object of axis 2). The studies focus on micelles of amphiphilic copolymers, induced micelles of double-hydrophilic block copolymers, either electrostatic complex micelles of polyions or complex coordination micelles type. A particular effort concerns the design and training of original structuring agents, generating both ordered mesostructures and functionalities as a preamble to the work of axis 2. The interactions between organic and inorganic bricks are also widely explored as they play a major role in the formation of the interface of structured hybrid nanomaterials.
|Permanent staff involved: Johan ALAUZUN, Karim BOUCHMELLA, Bruno BOURY, Nicolas BRUN, Carole CARCEL, Sylvain DUTREMEZ, Corine GERARDIN, Olinda GIMELLO, Gilles GUERRERO,Nathalie MARCOTTE, Ahmad MEHDI, Gaulthier RYDZEK, Rocio SEMINO, Nathalie TANCHOUX,Corine TOURNE-PETEILH, Michel WONG CHI MAN, Pascal YOT, Jurek ZAJAC.|
Materials engineering: control of structures, textures, morphologies and functionalities
The research activities of axis 2 are focused on the development of porous and hybrid materials by organic or inorganic polycondensation reactions according to soft and eco-designed pathways, in particular via aqueous, organic or non-hydrolytic sol-gel pathways.
Our projects are materials engineering, and aim to control textures and morphologies at molecular, mesoscopic and macroscopic scales. Shaping control ranges from the preparation of nanoparticles, films and fibers to monoliths. We are interested in the control of pore dimensions and organization, but also in the morphologies and functionalities of materials. The control of textures and morphologies is most often sought concomitantly, as in the case of materials with hierarchical porosity (case of meso-macroporous monoliths obtained by spinodal decomposition), mesoporous nanoparticles of controlled sizes, or gels of functional polysaccharides. Indeed, the objective is to develop new approaches that allow not only an intensification of the development paths of textured materials, but also ultimately an intensification of catalytic processes. In addition, the development paths we develop must meet, as much as possible, the principles of green chemistry, avoiding organic solvents, saving material and energy, and using renewable resources.
A wide range of materials is covered: crystalline porous materials such as zeolites and MOFs, inorganic or hybrid mesoporous materials with ordered structures (silica, titanium oxide, transition metal oxides, organosilice), functional hybrid materials, including hydrogels, functionalized PMO (Periodic Mesoporous Organosilica) silica, ionosilicas and ionogels, but also biosourced materials, including hydrocarbons, ionochars, activated carbons and aerogels.
Controlling the functionality of materials is a major goal. It includes the control of the nature, density and spatial distribution of functions by post-grafting approaches or by using precursors and functional structuring agents. The fields of application of the materials studied cover various fields such as catalysis, water separation/exchange and treatment, energy, gas storage, biology, fine chemistry or process engineering.
|Permanent staff involved: Johan ALAUZUN, Tangi AUBERT, Karim BOUCHMELLA, Nicolas BRUN, Thomas CACCIAGUERRA, Carole CARCEL, Jullien DRONE, Anne GALARNEAU, Pierrick GAUDIN, Corine GERARDIN, Gilles GUERRERO, Peter HESEMANN, Nathalie MARCOTTE, Ahmad MEHDI, Hubert MUTIN, Bénédicte PRELOT, Didier TICHIT, Corine TOURNE-PETEILH, Pascal YOT.
Adsorption and phenomena at interfaces
Research under this theme concerns the characterization and understanding of adsorption properties and interface phenomena on functional materials. The particularity of the ICGM in this field is to develop both experimental and theoretical methods, from liquid or gaseous phases, on solid surfaces or in porous materials. It is essentially a question of characterizing materials with large surface areas or with specific reactivities, whether they are developed within the department or resulting from external collaborations. These adsorption phenomena apply in many fields, and the fields of application are mainly related to sustainable development or health: separation, depollution, storage or conversion of energy, vectorization, catalysis and photocatalysis.
Experimental studies implement adsorption measurements using volumetric or gravimetric equipment developed in-house, coupled with calorimeters to access not only adsorption capabilities but also energy data from the interactions involved. A major objective is the characterization of surface chemistry and the prediction of the affinity of materials for species that may be pollutants, active ingredients or gases that are sought to separate. It is also possible to determine the composition of the vapour phase during adsorption, by coupling a gas cell and infrared measurement in situ. In situ XRD studies are also implemented to characterize the structural evolution of materials under the effect not only of adsorption but also of the coupled adsorption/mechanical stress action in the case of flexible MOFs, which requires a special effort for the development of adequate measurement cells. A chromatographic separation apparatus on a filled column also allows the study of the selectivity of materials on mixtures of organic liquids in the presence of moisture. These experimental approaches are, where appropriate, coupled step by step with theoretical approaches combining quantum methods and molecular force field modeling in order to predict the adsorption and separation properties of all the materials studied and beyond to understand the adsorption mechanisms at the microscopic scale, which is a particular asset of the department in this field.
Among the promising applications explored, we can mention the purification of air or natural gas with the development of MOFs for the selective capture of toxic molecules (CO2, SO2, NO2, H2S), the exploitation of MOFs, zeolites and functionalized mesoporous silica for the detection and capture of volatile organic compounds (acetic acid, formaldehyde …) in the context of the protection of heritage objects and embedded systems in the field of space (CNES) or the use of porous carbons and MOFs for the protection of civilians and military personnel vis-à-vis chemical weapons.
Beyond their fundamental interest, flexible MOFs materials are also considered for their use in the field of gas separation. We develop an experiment/simulation approach (Molecular Dynamics based on the use of flexible force fields) to address the complexity of these systems that has made it possible to predict new concepts of CO2 capture based on the use of flexible MOFs whose porosity opening is controlled by the application of an electric field or mechanical pressure to allow the selective adsorption of CO2 vis-à-vis other molecules such as CH4 and N2. This same concept was then applied to the separation of propane/propylene.
On the other hand, we are interested in the physicochemistry of solid/liquid interfaces in inorganic, hybrid or polymer nanostructured materials. The main objectives are the understanding of the interactions involved and the organization of adsorbed species at interfaces, the analysis of competitive and/or synergistic effects between surface chemistry, interfacial water structure, as well as adsorption and solvation effects. Multi-scale approaches to the adsorption of ions and molecules by these nanostructured materials are underway, and they rely on nonlinear optics techniques, from the assembly and development of experimental devices, to signal modeling, as well as other local techniques, specific to interfaces, in situ and operando, on large instruments (X-ray absorption with EXAFS and XANES, XPS in ambient conditions). These projects are related to the fields of health and the environment, with applications in separation, encapsulation, vectorization, depollution and decontamination. In particular, water remediation and liquid effluent treatment are at the heart of the applications explored. In addition, we continue to pay particular attention to the modeling of phenomena at solid/solid interfaces that are present in composite systems formed by the combination of polymers or graphene oxides and MOFs. This theme, which involves the development of new multi-scale modeling tools, involves the exploration of molecular transport within these composite systems.
Among the properties of hybrid and inorganic materials, we explore proton conduction properties using complex impedance spectroscopy measurements coupled with numerical simulations to identify the best candidates for this application and beyond propose the microscopic mechanisms behind these properties. These studies have already highlighted a series of MOFs whose conductivities approach the performance of those of Nafion.
In addition, an original approach of axis 4 concerns the development of molecular simulation tools and force fields not only to predict by High-Throughput screening approaches (Monte Carlo & Molecular Dynamics) but also to rationalize the performance of a wide variety of porous solids to ultimately discover new architectures in silico and thus direct the synthesis towards innovative materials. Through strong interactions with internationally recognized groups in the field of porous material synthesis, these advances have already made it possible to identify new porous materials with exceptional performance for applications in the field of adsorption of toxic gases, space domain contaminants and water for applications in heat transfer. We can highlight several examples with the MIL-100, KAUST-8 and KMF-1 MOFs, which appear as adsorbents with unique performance for natural gas and air purification and for applications in the field of heat pumps. These molecular modeling approaches are coupled with adsorption measurements and sensor tests carried out in-house. Quantum simulation approaches (DFT and ab initio) also make it possible to study locally the interactions between molecules and adsorption sites and beyond derive new force fields.
|Permanent staff involved: Johan ALAUZUN, Tangi AUBERT, Karim BOUCHMELLA, Nicolas BRUN, Thomas CACCIAGUERRA, Carole CARCEL, Jullien DRONE, Anne GALARNEAU, Pierrick GAUDIN, Corine GERARDIN, Gilles GUERRERO, Peter HESEMANN, Nathalie MARCOTTE, Ahmad MEHDI, Hubert MUTIN, Bénédicte PRELOT, Didier TICHIT, Corine TOURNE-PETEILH, Pascal YOT.|
Heterogeneous catalysis and surface reactivity
The study of the surface reactivity of porous and hybrid materials and the study of their catalytic properties are grouped within axis 4. The approaches followed are both fundamental and applied. They combine experimental and theoretical studies, mainly quantum, which is a strength of the department. The performance of functional materials developed by green chemistry approaches within the department is evaluated in heterogeneous catalysis processes including biocatalysis, organocatalysis, photocatalysis and electrocatalysis. Conversely, the intended application can sometimes also guide the specifications of the appropriate catalytic material.
Among the major topics addressed, we must mention the catalytic valorization of small molecules. In particular, the transformation and valorization of CO2 are explored using mainly fundamental approaches, in particular with catalysts of large specific surface area of mixed oxide type obtained from polysaccharide complexes. The bio-(electro)catalytic recovery of CO2 is also studied via the immobilization of enzymes on porous and/or hybrid carbon supports.
The valorization of biomass is a priority of the department’s catalysis research, in particular through projects on the extraction and depolymerization of lignin to obtain platform molecules. On the other hand, activities focused on the catalytic conversion of bio-sourced molecules into biofuels by multifunctional materials with hierarchical porosity, such as zeolites with organized mesoporosity, are developed. Another example is the catalytic production of large intermediates (eg. light olefins) from bioethanol. Fine chemistry applications are studied in the presence of catalysts supported on foams from bio-resources such as functional alginates. Another topic addressed concerns the evaluation of the heterogeneous catalysis performance of innovative ordered mesoporous materials, functionalized by functional polymer chains whose nature and density of functions can be controlled. Particular interest is given to materials with controlled acidic properties.
Regarding the intensification of processes in catalysis, electrocatalysis, and biocatalysis with immobilization of enzymes, the development of new zeolithic, silic, alumina or carbonaceous monoliths makes it possible to optimize the material and heat transfer properties for a large number of applications: oligomerization and metathesis of ethylene, the valorization of methyl mercaptan and its conversion into olefins and aromatics, the valorization of CO2 and water and soil remediation. For applications requiring high flow rates and low pressure drop, such as biocatalytic treatment of water containing pharmaceutical molecules or pesticides, monoliths with large macropore diameters are required. Syntheses of monoliths of silica, alumina, carbon and zeolites (LTA, FAU-X, ZSM-5, MOR, FAU-Y, BEA) are currently being developed inside three-dimensional structure molds prepared by polymer 3D printing. The grafting of enzymes on silicic and carbonaceous monoliths is optimized for biocatalytic treatments. Finally, catalysis by transition metal ions in porous materials continues to be developed within the department, by quantum chemistry methods, in close connection with experimental data.
It is necessary to underline the coherence of the studies developed in this axis, which combine 1) the use of catalytic materials prepared by green chemistry routes, and in particular from renewable resources, 2) the development of approaches aimed at intensifying catalytic processes and finally 3) projects targeting catalysis challenges related to the fields of bio-resource valorization and environmental protection. Finally, it should be added that catalytic transformations concern source compounds that cover a wide range of C1 molecules to natural polymers of high molecular weight.
|Permanent staff involved: Dorothée BERTHOMIEU, Christine BIOLLEY, Bruno BOURY, Nicolas BRUN, Claudia CAMMARANO, Gérard DELAHAY, Francesco DI RENZO, Jullien DRONE, Anne GALARNEAU, Pierrick GAUDIN, Olinda GIMELLO, Vasile HULEA, Hugo PETITJEAN, Nathalie TANCHOUX, Didier TICHIT, Michel WONG CHI MAN.|