Design of functional nanostructured materials using supercritical fluids

Abstract

International audienceThis paper describes how the specific properties of supercritical fluids have been exploited in the last 5 years for synthesizing functional nanostructured materials, especially in the field of inorganic and hybrid materials. It is shown that control of the physicochemical properties of nanomaterials (size, morphology, structure and composition) as "nanobricks" is achieved by choosing specific operating parameters. Next, the structure formation of these "nanobricks" is discussed in order to design advanced nanostructured materials. This is illustrated with the design of nanorods, nanowires, conformational films, core-shell structure, supported nanoparticles, polymer impregnation with nanoparticles and organic coating of particles. The associated properties for applications in many interesting fields, such as catalysis, electronics, energy, optics, etc. are reported

Synthetic versatility of nanoparticles: A new, rapid, one-pot, single-step synthetic approach to spherical mesoporous (metal) oxide nanoparticles using supercritical alcohols

“…However, these techniques generally require long reaction times (several hours) and complex multistep operations [1-43, 47, 48]. Recently, supercritical fluids have been applied in the synthesis of size-and morphology-controlled inorganic-organic hybrid metal and MO NPs [49][50][51][52][53][54][55][56][57][58][59][60][61]. All of these reported NP syntheses occur rapidly in supercritical fluids (several seconds to several minutes) [56][57][58][59][60][61].…”

Versatility of one-pot, single-step synthetic approach for spherical porous (metal) oxide nanoparticles using supercritical alcohols

“…Supercritical ethanol (scEtOH) yields monodisperse metal nanoparticles [29], supercritical methanol (scMeOH) [30,31] or supercritical water (SCW) [32] yields zinc oxide (ZnO) nanoparticles, while SCW alone yields CeO 2 [33], TiO 2 [34], and magnetite (Fe 3 O 4 ) [35] nanoparticles. All of these reactions proceed in a short reaction time (several seconds to several minutes) [36][37][38][39][40][41]. However, a versatile synthetic method for MARIMO nanoparticles in supercritical fluids has yet to be established.…”

Synthesis of TiO2 nanoparticles on mesoporous aluminosilicate Al-SBA-15 in supercritical CO2 for photocatalytic decolorization of methylene blue

“…Sc-CO 2 with unique properties such as low viscosity, high diffusivity, near zero surface tension, ease of complete separation from the reaction products by simply controlling the temperature or pressure, etc, has been the focus of many researches for developing green processes to prepare nanostructured materials [18,19]. Good solvation properties of Sc-CO 2 are able to facilitate the transfer of metal precursors into SBA-15 channels to generate nanoparticles without blockage of mesopores.…”