Preparation of catalysts from microemulsions and their applications in heterogeneous catalysis

Recent Advances in the Liquid‐Phase Synthesis of Metal Nanostructures with Controlled Shape and Size for Catalysis

“…Another widespread technique for preparation of monodispersed spherical nanoparticles with a controlled size for catalytic applications is a microemulsion (ME) technique (37,(55)(56)(57). Water-in-oil (reverse) ME have been generally used for the synthesis of a variety of ultrafine metal particles (55) but there are also some examples of metal nanoparticle formation in normal microemulsions (oil-in-water) (58).…”

“…Water-in-oil (reverse) ME have been generally used for the synthesis of a variety of ultrafine metal particles (55) but there are also some examples of metal nanoparticle formation in normal microemulsions (oil-in-water) (58). The main advantage of ME as spatially confined nanoreactors of 5-100 nm size is their one-pot fabrication without sophisticated, time-consuming synthetic steps (4).…”

“…The MEs allow obtaining monodispersed particles with a standard deviation from the average diameter of less than ¡10%. Monodispersity is thermodynamic in nature as a system has a minimum free energy at a definite volume fraction of the dispersed phase governing a droplet size (4,6,55). Metal salts are typically introduced into the droplets of dispersed phase of reverse ME and then reduced either by mixing with another reverse ME containing reductant (hydrazine), or by direct introduction of the reductant into the metal precursor-containing ME (e.g., hydrogen).…”

“…5 (59). These particles were prepared in water/ AOT/hydrocarbon microemulsions, which are considered to be an ideal media to synthesize nanoparticles due to the well-established structural and dynamic properties of AOT reversed micelles, the surfactant's ability to solubilize relatively large amounts of water without a co-surfactant and the high stability of microemulsions (55,59). The reverse ME technique allowed producing Pd, Pt, Au, Rh, Fe, and Cu nanoparticles of the controlled size, some of them were successfully used for catalytic applications, including size effect studies (55-57, 60, 61).…”

Monodispersed Pd-nanoparticles on carbon fiber fabrics as structured catalyst for selective hydrogenation

“…The highest activity in 1-butyne hydrogenation was observed with Pd dispersions < 20% (Boitiaux et al, 1983). To achieve Pd nanoparticles monodispersion on ACF support, we prepared Pd/ACF catalysts (Semagina et al, 2006) with monodispersed particles of ∼ 8 nm diameter via a modified reverse microemulsion technique (Eriksson et al, 2004). The present paper reports on the kinetics of 1-hexyne liquid phase hydrogenation over the novel microemulsion-derived Pd/ACF catalysts.…”