A new palladium nanoparticle catalyst on mesoporous silica prepared from a molecular cluster precursor

Abstract

A promising approach to the controlled synthesis of supported nanoparticles involves the use of molecular carbonyl clusters as precursors. Molecular metal clusters consist of a defined number of structurally ordered atoms, and active monodisperse metal particles are formed after dispersing the molecules and removing the ligands. An octanuclear palladium cluster precursor with easily displaceable ligands was used to generate palladium nanoparticles on mesoporous MCM-41. The molecular cluster precursor, [Pd8(CO)8(PMe3)7], was directly adsorbed from solution onto MCM-41, followed by gentle thermolysis which yielded small metal nanoparticles. Compared to MCM-41-based catalysts prepared from palladium salts by conventional methods, this cluster-derived palladium catalyst has shown an efficient activity for liquid-phase hydrogenation of alkenes.

Homogeneous/heterogeneous palladium based catalytic system for Heck reaction. The reversible transfer of palladium between solution and support

“…However, recently the high catalytic activity of ligand-free soluble Pd colloids was also demonstrated [13][14][15][16]. Furthermore, heterogenization of catalysts has attracted significant interest, offering easier separation of the catalyst from organic products [17][18][19][20][21][22][23]. However, the studies of catalytic activity of the heterogenized Pd catalysts clearly demonstrated existence of significant Pd leaching and important contribution of a soluble catalyst, apart of the heterogenized one, in the main reaction course [24][25][26][27][28][29][30].…”

Synthetic Routes to the Encapsulation of II–VI Semiconductors in Mesoporous Hosts

“…Incorporating clusters within mesoporous frameworks has been studied extensively,57 and the development of condensed nanoparticle structures within the framework from these cluster precursors is also of interest 57a–57d. Recently, it was demonstrated that [Cu 6 (TePh) 6 (PPh 2 Et) 5 ] can be loaded into the pores of MCM‐41 at 110 °C 58.…”

In situ immobilization of tin dioxide nanoparticles by nanoporous polymers scaffold toward monolithic humidity sensing devices

“…To date, a large number of strategies such as spin coating [14], assembly of nanobuliding blocks into bulky materials [15], growth on substrates [16], large-surface-area supporters [17][18][19], formation of composite materials [20][21], and high temperature agglomeration [22] have been successfully employed to immobilize nanomaterials towards the tractable fabrication of micro-nanodevices. Nonetheless, the immobilization treatments would more or less limit their properties as compared with pristine nanomaterials.…”