Odyssey in Polyphasic Catalysis by Metal Nanoparticles

Abstract

Nanometer-sized metal particles constitute an unavoidable family of catalysts, combining the advantages of molecular complexes in regards to their catalytic performances and the ones of heterogeneous systems in terms of easy recycling. As part of this research, our group aims at designing well-defined metal nanoparticles based-catalysts, in non-conventional media (ionic liquids or water), for various catalytic applications (hydrogenation, dehalogenation, carbon-carbon coupling, asymmetric catalysis) in mild reaction conditions. In the drive towards a more eco-responsible chemistry, the main focuses rely on the search of highly active and selective nanocatalysts, in association with an efficient recycling mainly under pure biphasic liquid-liquid conditions. In this Personal Account, we proposed our almost fifteen-years odyssey in the world of metal nanoparticles for a sustainable catalysis.

Selective Aerobic Oxidation of Benzyl Alcohols with Palladium(0) Nanoparticles Suspension in Water

“…Beside these supported-metal catalysts, a recent approach based on metal suspensions in a solvent gives dispersed (colloidal) nanoparticles having catalytic behaviour often considered as "quasi-homogeneous" [14][15][16][17]. If water is used as solvent, a stabilizer soluble in water is required and several systems have been reported to date especially for noble metals [18]. In the case of Pd aqueous suspensions, Pd chloride salts are often used as precursors in the presence of water soluble stabilizers like polymers (polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene diamine, polystyrene, polyethylene glycol) [19][20][21][22][23], short-and long-chain surfactants [24,25], calixarenes, cyclodextrins [26,27], natural ligand (glucose, starch, proteins) [28][29][30] and P-or P-O-based ligands [31,32].…”

Rhodium nanoparticles inside well-defined unimolecular amphiphilic polymeric nanoreactors: synthesis and biphasic hydrogenation catalysis

“…Since the RhNP@CCM-N catalytic efficiency is very high (entries [24][25][26][27], experiments were carried out only up to 60 C. Full substrate conversion was already achieved in 20 h at 25 C, with high selectivity for the vinyl group hydrogenation. Only traces of the nal product 7 were observed at 25 C for the NPs produced with P/Rh ¼ 1 (entry 24) and this increased only slightly when operating at 60 C (entry 25).…”

“…25,26 Ligand-stabilized metal NPs may be involved in catalysis as colloidal suspensions in water, polyols or organic solvents and several strategies have been developed to facilitate the catalyst recovery. 27 Among the available strategies for catalyst recovery and recycling, aqueous biphasic catalysis is particularly attractive when the catalyst can be conned in the aqueous phase, because the organic reaction products can be easily separated by decantation. However, the reaction may be severely limited by mass transport if the catalyst is totally insoluble in the organic reactant/product phase and if the reactants are totally insoluble in water, limiting the productive process to the organic/water interface.…”

Remediation of Diethyl Phthalate in Aqueous Effluents with TiO2-Supported Rh0 Nanoparticles as Multicatalytic Materials

“…In the last decades, nanometer-sized particles have been considered as p and green catalysts, owing to their unique surface properties, thus affording rele tivities and original selectivities [45]. In that context, we have developed the eco sible synthesis of aqueous suspensions of metal nanoparticles as active catalytic [46,47] and their easy deposition without a calcination step on various supports, in TiO2 [48].…”