Recent advances in the development of magnetically recoverable metal nanoparticle catalysts

Abstract

O objetivo deste Account é fornecer uma visão geral de nossas atividades atuais de pesquisa, as quais envolvem a síntese e modificação de nanomateriais superparamagnéticos para aplicação na área de separação magnética e catálise. Primeiramente, uma introdução ao magnetismo e à separação magnética é feita. Em seguida, estratégias sintéticas que têm sido desenvolvidas para gerar nanopartículas superparamagnéticas revestidas esfericamente por sílica e outros óxidos, com destaque a sistemas bem caracterizados e preparados por metodologias que geram amostras de elevada qualidade e que, a princípio, podem ser produzidas em maior escala, são discutidas. Uma série de catalisadores magneticamente recuperáveis preparados em nosso grupo de pesquisa pela combinação única de suportes superparamagnéticos e nanopartículas metálicas é destacada. Este Account é concluído com observações pessoais e perspectivas neste campo de pesquisa.The aim of this Account is to provide an overview of our current research activities on the design and modification of superparamagnetic nanomaterials for application in the field of magnetic separation and catalysis. First, an introduction of magnetism and magnetic separation is done. Then, the synthetic strategies that have been developed for generating superparamagnetic nanoparticles spherically coated by silica and other oxides, with a focus on well characterized systems prepared by methods that generate samples of high quality and easy to scale-up, are discussed. A set of magnetically recoverable catalysts prepared in our research group by the unique combination of superparamagnetic supports and metal nanoparticles is highlighted. This Account is concluded with personal remarks and perspectives on this research field.

The Current Status of Heterogeneous Palladium Catalysed Heck and Suzuki Cross-Coupling Reactions

“…Recent studies show that magnetic nanoparticles are excellent supports for various catalysts [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ]. Additionally, the magnetic properties can be exploited to improve catalyst separation from previous filtration and centrifugation methods.…”

Separation technology meets green chemistry: development of magnetically recoverable catalyst supports containing silica, ceria, and titania

“…This method was chosen due to the high quality of the magnetic materials -spherically coated with silica -obtained with this methodology. We have been using this material as a catalyst support for metal nanoparticles [2,[12][13][14][15][16][17][18], metal complexes [19], and enzymes [20,21] to perform a large scope of reactions. All the reactions have been performed at relatively mild conditions (<373 K) because the stability of the Fe 3 O 4 @SiO 2 material upon thermal treatment has never been studied in detail.…”

“…The magnetic support Fe 3 O 4 @SiO 2 was prepared by a microemulsion process reported elsewhere [12]. The influence of reaction time on the silica layer was studied by taking aliquots with 2, 6, 12, 24, and 48 h. The material was precipitated with methanol and separated by centrifugation.…”

Highly Active Ruthenium Catalyst Supported on Magnetically Separable Mesoporous Organosilica Nanoparticles

“…MNPs have received a great deal of attention because of their low costs, high surface areas, negligible toxicity, and their superparamagnetic properties [66][67][68][69]. Owing to their unique properties, magnetic nanoparticles have become highly welcome in many biological [70][71][72][73][74][75], chemical [76][77][78][79][80][81][82][83][84], and biomedical domains [85][86][87][88][89][90][91]. Lately, very few research groups have reported the preparation of magnetically recoverable PMO nanomaterials for different applications [92][93][94][95][96][97].…”