Gold nanoparticles supported onto amine-functionalized in-capillary monoliths meant for flow-through catalysis: A comparative study. (16th September 2021)

• Record Type: Journal Article
• Authors: Poupart, Romain; Guerrouache, Mohamed; Grande, Daniel; Le Droumaguet, Benjamin; Carbonnier, Benjamin
• Is Part Of: Polymer. Volume 230(2021)
• Publication Date: 2021-09-16
• Subjects: Gold nanoparticles -- Catalytic reduction -- Monolith -- Amino-functionalization -- Polymer-supported nano-metal; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.124014
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Monoliths functionalized with ethylene diamine-derived ligands were synthetized within micro-sized channels as highly permeable catalytic supports for the immobilization of in-situ generated gold nanoparticles. The as-obtained hybrids, essentially differing on the grafted amine-containing ligands were compared, notably regarding the immobilized nanoparticles morphology and their dispersion at the monolith pore surface. Further, such in-capillary hybrid monoliths were successfully applied as flow-through microreactors for the catalytic reduction of nitroaromatic compounds. The general synthetic route for preparing these composite materials consisted in a three-step procedure involving ( i ) UV-induced polymerization of N -acryloxysuccinimide and ethylene glycol dimethacrylate in toluene, ( ii ) surface grafting of a series of ethylene diamine derivatives through nucleophilic substitution of N -hydroxysuccinimide leaving groups, and ( iii ) successive in situ reduction of tetrachloroauric acid to generate monolith-adsorbed gold nanoparticles. The successful synthesis of such hybrid monoliths was ascertained by in-situ Raman spectroscopy, EDX analysis and SEM observations. Microscopy demonstrated the key role of the grafted amine-bearing ligand regarding the morphology, size and surface coverage of the immobilized gold nanoparticles at the monolith pore surface. Monolith-adsorbed gold nanoparticles exhibited good catalytic activities towards the conversion of nitroaromatic compounds into the corresponding amino derivatives in a flow-through process. This study clearly demonstrates the key role of the nature, primary vs. secondary, of the chelating amine in the morphology (shape, size, dispersion) of the supported gold nanoparticles. Graphical abstract: Image 1 Highlights: In situ synthesis of hybrid porous polymer-nanoparticle composites within microchannels. One-step functionalization of the monoliths with amine-containing chelatants of varied chemical nature and topology. Dispersion, size and morphology of nanogold depend on the nature of the surface-grafted amine. Successful continuous flow catalytic reduction of nitroarenes using porous polymer-nanoparticle composites as microreactors.