The SFFM group focuses its research in the use of Supercritical CO2 for the design and preparation of functional materials for a wide variety of applications ranging from energy and environment to biomedical applications
scCO2 and general applications
scCO2 is a non-toxic and environmentally benign green solvent that has been widely used in the food and pharmaceutical industries. However, scCO2 (which reaches its supercritical conditions at 31.1 °C and 7.4 MPa) also has many outstanding properties, which give it a great potential for advanced synthesis and materials processing. In particular, it is an attractive alternative to organic solvents that are widely recognized as pollutant or toxic. ScCO2 is a non-destructive fluid with null surface tension, thus adequate to create or manipulate complex primary nanoparticles, functional nanomaterials and nanostructures. Moreover, the low viscosity of the compressed fluid and its high diffusivity allow for exceptionally effective penetration in nanopores.
The overall objective of the SFFM group is to use this clean supercritical fluid technology, coupled with other chemical processing approaches, as a platform to develop flexible manufacturing routes for the cost-effective production of nanoporous materials as well as 3D nanostructures using sustainable processes. scCO2 technology is used for the production of high performance existing and new products with unique characteristics in regard to composition (purity), size (micro or nanoscale) and architecture (fibres, foams).
The SFFM research group pioneered the synthesis of coordination polymers in scCO2, showing that this fluid can act simultaneously as solvent and activation agent.
MOFs are hybrid network structures formed by self-assembly of metal ions or clusters and organic linking groups. These structures have a great variety of applications in catalysis, drug delivery, or gas separation and storage.
In this research topic, we propose an attractive synthetic method for the preparation of MOFs and coordination polymers. These hybrid materials can be obtained by using bidentate and tridentate N donor ligands, such as bipyridyl and triazine derivative organic linkers, respectively. Among the coordination polymers based on M2+ transition metals, there is a large variety of structural motifs when reacted with the different linkers, including simple and sinusoidal 1D chains, 2D double helices with simple and interpenetrating layers and even 3D frameworks.
Since the first synthesis of a coordination polymer using scCO2, more than 25 structures have been synthesised, from rigid to flexible structures, as well as very well known MOFs using carboxylate linkers such as ZIF-8, H-Kust-1 or MIL-100 (Fe).
BIO-MOFs. A promising field of application of MOFs is the biomedical one. In this case, it is a bioactive molecule, such a curcumine, the linker in the MOF network
We own a patented technology for producing GO aerogels starting from an alcoholic dispersion of graphene oxide. The procedure is developed under isothermal and isobaric conditions, and it is readily reproducible, scalable and cost-effective, leading to a non-reduced end-product.
The aerogel obtained combines stability and robustness with a high functionalization capacity granted by the large number of functional groups maintained from the starting graphene oxide. Aerogels obtained have a high surface area, ca. 250 m2/g, and a high pore volume, between 0.9 and 1.5 mL/g.
The possibility of preparing multifunctional composites using graphene oxide as a basic unit for the controlled self-assembly of 3D carbon macrostructures by supercritical CO2 is enormous. Possible applications include adsorption material in membrane technologies, batteries, supercapacitors, metal catalyst supports, among others.
In particular, composites of metal nanoparticles and GO aerogels are promising for a myriad of applications. As an example, the development of an all-green synthesis approach allowed the preparation of hybrid materials shaped into aerogels with large mesoporosity, involving the loading of SPIONs onto a GO surface via a simple one-pot supercritical CO2 technique for MRI applications