Processes using supercritical fluids: A sustainable approach for the design of functional nanomaterials

The concepts of green chemistry and sustainable development are being considered more and more due to the evolution of regulations and mentalities. In this context, the development of supercritical fluid technologies should go on to evolve in the right direction. Since the nineteen fifties, studies and development efforts have been focused on new ways of separating substances using the specific properties of supercritical fluids. In this context, a mention must be made about the use of carbon dioxide as an extracting agent in many industrial processes (decaffeination of coffee and tea, extraction of hops, spice, aromatic substances, fragrances, pharmaceuticals, etc). Processes using these fluids are particularly attractive at the industrial scale in many fields such as impregnation, analytical and preparative separations, organic synthesis, waste management and material recycling. The industrial development of the supercritical fluid technology is accompanied by numerous research activities, in particular, in the field of inorganic Materials Science for the synthesis of multifunctional nanomaterials. Today, supercritical fluid technology allows the production, with a reduction of the environmental impact, of well designed nanomaterials with controlled properties for applications in many interesting fields, such as catalysis, electronics, energy, optics, pharmacology, etc. This paper is focused on the interest of using supercritical fluids to overcome the drawbacks of solution chemistry approaches for designing multifunctional nanomaterials in term of chemical engineering, sustainable chemistry and control of size, morphology, composition and the structure of nanomaterials.