Palladium Nanoparticles Supported on Fibrous‐Structured Silica Nanospheres (KCC‐1): An Efficient and Selective Catalyst for the Transfer Hydrogenation of Alkenes

Abstract

An efficient palladium catalyst supported on fibrous silica nanospheres (KCC‐1) has been developed for the hydrogenation of alkenes and α,β‐unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high‐resolution TEM, chemisorption) with analogous mesoporous (MCM‐41, SBA‐15) silica‐supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC‐1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC‐1‐supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.

A general post-synthetic modification approach of amino-tagged metal–organic frameworks to access efficient catalysts for the Knoevenagel condensation reaction

“…S27g). 32 Similarly, Al-MIL-53, Al-MIL-53-NH 2 and Al-MIL-53-NH-RNH 2 were prepared as alternative MOF catalysts for investigation. The morphologies of aminotagged MOFs were retained according to SEM images (Fig.…”

Cycloadditions to Epoxides Catalyzed by Group III–V Transition‐Metal Complexes

“…[53] In an early approach,S rivastava et al have reported the incorporation of Ti + 4 and Al + 3 ions in mesoporousS BA-15s ilica to create acidic surfaces ites. [54] The same materials were functionalized with basic moieties by grafting primary amines and aromatic amines such as imidazole, guanidine, and adenine.…”

Gold Nanoparticles Supported on Fibrous Silica Nanospheres (KCC‐1) as Efficient Heterogeneous Catalysts for CO Oxidation

“…Following reduction, its interaction with the NPs promotes dispersion and prevents sintering and leaching. It has been employed for the preparation of well‐spaced and uniformly dispersed Au nanoparticles on mesoporous silica, as well as for Pd, Ag, and Ru nanoparticles on the surface of KCC‐1 and on other supports . Au NPs prepared on MCM‐41 without amino‐functionalization of the surface showed a very broad size distribution and a high tendency towards sintering .…”

“…These features have been exploited for the preparation of highly active catalysts and CO 2 sorbents . We have previously demonstrated that Pd NPs supported on amino‐functionalized KCC‐1 were more accessible for interaction with CO and H 2 than on analogous amino‐functionalized traditional supports such as MCM‐41 and SBA‐15 . This result was found to have a remarkable impact on the catalytic performance of the supported species.…”