Magnetically Separable Nanocatalysts: Bridges between Homogeneous and Heterogeneous Catalysis

Synthesis of small-sized, porous, and low-toxic magnetite nanoparticles by thin POSS silica coating

In this communication, we report the synthesis of small-sized (<10 nm), water-soluble, magnetic nanoparticles (MNPs) coated with polyhedral oligomeric silsesquioxanes (POSS), which contain either polyethylene glycol (PEG) or octa(tetramethylammonium) (OctaTMA) as functional groups. The POSS-coated MNPs exhibit superparamagnetic behavior with saturation magnetic moments (51-53 emu g(-1)) comparable to silica-coated MNPs. They also provide good colloidal stability at different pH and salt concentrations, and low cytotoxicity to MCF-7 human breast epithelial cells. The relaxivity data and magnetic resonance (MR) phantom images demonstrate the potential application of these MNPs in bioimaging.

Multifunctional Au-Fe3O4@MOF core-shell nanocomposite catalysts with controllable reactivity and magnetic recyclability

The recovery and reuse of expensive catalysts are important in both heterogeneous and homogeneous catalysis due to economic and environmental reasons. This work reports a novel multifunctional magnetic core-shell gold catalyst which can be easily prepared and shows remarkable catalytic properties in the reduction of 4-nitrophenol. The novel Au-Fe3O4@metal-organic framework (MOF) catalyst consists of a superparamagnetic Au-Fe3O4 core and a porous MOF shell with controllable thickness. Small Au nanoparticles (NPs) of 3-5 nm are mainly sandwiched between the Fe3O4 core and the porous MOF shell. Catalytic studies show that the core-shell structured Au-Fe3O4@MOF catalyst has a much higher catalytic activity than other reported Au-based catalysts toward the reduction of 4-nitrophenol. Moreover, this catalyst can be easily recycled due to the presence of the superparamagnetic core. Therefore, compared to conventional catalysts used in the reduction of 4-nitrophenol, this porous MOF-based magnetic catalyst is green, cheap and promising for industrial applications.

Insights into mesoporous metal phosphonate hybrid materials for catalysis

Mesoporous metal phosphonates have received increasing attention as promising heterogeneous catalysts due to their abundant framework compositions and controllable porosity.

A facile synthesis of Pt@Ir zigzag bimetallic nanocomplexes for hydrogenation reactions

A facile approach for the synthesis of Pt@Ir zigzag bimetallic nanocomplexes with high catalytic activity.

Magnetic nanoparticle-supported imidazole tribromide: a green, mild, recyclable and metal-free catalyst for the oxidation of sulfides to sulfoxides in the presence of aqueous hydrogen peroxide

Imidazole tribromide immobilized on magnetic nanoparticles as a bromine source was prepared and characterized by XRD, TGA, FT-IR, EDS, scanning and transmission electron microscopy, and vibrating sample magnetometer techniques.

The catalytic evaluation of in situ grown Pd nanoparticles on the surface of Fe3O4@dextran particles in the p-nitrophenol reduction reaction

We report the catalytic activity evaluation of in situ grown Pd nanoparticles on the surface of superparamagnetic Fe₃O₄ particles coated with the natural polymer dextran, in the reduction of p-nitrophenol (Nip), in water, by sodium borohydride.

Magnetic cellulose–TiO2 nanocomposite microspheres for highly selective enrichment of phosphopeptides

Novel magnetic cellulose–TiO₂ nanocomposite microspheres were prepared successfully by in situ synthesis of TiO₂ nanoparticles in the micro/nanopores of cellulose–Fe₃O₄ microsphere, which exhibited highly selective enrichment of trace phosphopeptides, as a result of the high-efficiency Lewis acid–base reaction.

Synergic effect of nano-catalyst and continuous flow system: Dakin–West reaction catalyzed by Nafion-H@SPIONs in a microreactor

The expansion of practical processes for superferromagnetic nanocatalysts is a very attractive subject.

Preparation and characterization of magnetic nanocomposite catalysts with double Au nanoparticle layers

Nanocomposite catalysts, with single and double gold layers, and with one gold layer and one silver layer were prepared through simple steps, and showed excellent activity in the reduction of nitrophenols.

Nickel Schiff-base complexes immobilized on boehmite nanoparticles and their application in the oxidation of sulfides and oxidative coupling of thiols as novel and reusable nano organometal catalysts

Ni-complex-boehmite was prepared in water at room temperature using commercially available materials and applied as an efficient nanocatalyst in the oxidation of sulfides and thiols.

A cheap and efficient catalyst with ultra-high activity for reduction of 4-nitrophenol

Ni/SBA-15 catalyst with ultra-small particle size (7 nm), good dispersion, and ultra-high loading amount (57.4%) of Ni nanoparticles was prepared by a unique in situ thermal decomposition and reduction route. It exhibits excellent catalytic activity and stability for 4-nitrophenol reduction.

Synthesis and characterization of glucosulfonic acid supported on Fe3O4 nanoparticles as a novel and magnetically recoverable nanocatalyst and its application in the synthesis of polyhydroquinoline and 2,3-dihydroquinazolin-4(1H)-one derivatives

Synthesis and characterization of glucosulfonic acid supported on Fe₃O₄ nanoparticles as novel and magnetically recoverable nanocatalyst and its application in the synthesis of polyhydroquinoline and 2,3-dihydroquinazolin-4(1H)-one derivatives.

A Pd complex of a NNN pincer ligand supported on γ-Fe2O3@SiO2 as the first magnetically recoverable heterogeneous catalyst for C–P bond forming reactions

A Pd complex of the NNN pincer ligand supported on γ-Fe₂O₃@SiO₂ was used as a new catalyst for a phosphonation reaction.

Facile and surfactant-free synthesis of Pd nanoparticles by the extract of the fruits of Piper longum and their catalytic performance for the Sonogashira coupling reaction in water under ligand- and copper-free conditions

This work reports a facile synthesis of palladium nanoparticles (Pd NPs) by the extract of the fruits of Piper longum without any stabilizer or surfactant.

Synthesis of a new class of pyrazole embedded spirocyclic scaffolds using magnetically separable Fe3O4@SiO2–SO3H nanoparticles as recyclable solid acid support

A green methodology for the synthesis of a new class of pyrazole embedded spirocyclic scaffolds has been developed using Fe₃O₄@SiO₂–SO₃H magnetic nanoparticles.

1-Methyl-3-(propyl-3-sulfonic acid)imidazolium triflate supported on magnetic nanoparticles: an efficient and reusable catalyst for synthesis of mono- and bis-isobenzofuran-1(3H)-ones under solvent-free conditions

An efficient procedure for the synthesis of isobenzofuran-1(3H)-one derivatives in the presence of [HSO₃PMIM]OTf–SiO₂@MNPs as a highly recyclable catalyst under solvent-free thermal conditions and MW irradiation is reported.

Synthesis of polyurethane containing carbon–carbon double bonds to prepare functionalizable ultrafine fibers via electrospinning

This work suggests a feasible methodology to produce a functionalized ultrafine fibrous carrier with the capacity to fabricate solid catalysts in the future.

Magnetically separable Fe3O4–SO3H nanoparticles as an efficient solid acid support for the facile synthesis of two types of spiroindole fused dihydropyridine derivatives under solvent free conditions

Two types of spiroindole fused dihydropyridine derivatives have been synthesised from isatins under solvent-free conditions using magnetically separable Fe₃O₄–SO₃H nanoparticles.

Magnetically retrievable lepidocrocite supported copper oxide nanocatalyst (Fe–CuO) for N-arylation of imidazole

A novel magnetically separable Fe–CuO is prepared by a simple precipitation method and is found to be an effective and reusable heterogeneous catalyst for ligand-free N-arylation reaction.

Ethylenediamine-functionalized magnetic Fe3O4@SiO2 nanoparticles: cooperative trifunctional catalysis for selective synthesis of nitroalkenes

The designed nanocatalyst Fe₃O₄@SiO₂–NH₂ was highly active for selective synthesis of nitroalkenes through cooperative trifunctional catalysis of primary amine, secondary amine and Si–OH groups.

Mechanochemical surface functionalisation of superparamagnetic microparticles with in situ formed crystalline metal-complexes: a fast novel core–shell particle formation method

An innovative mechanochemical method is reported for the in situ formation of crystalline metal-complexes on the surface of superparamagnetic nanocomposite microparticles.

Magnetic polymer nanocomposite-supported Pd: an efficient and reusable catalyst for the Heck and Suzuki reactions in water

Pd supported on magnetic polymer nanocomposites serves as an efficient and recyclable catalyst for the water-phase Heck and Suzuki reactions.

Biosynthesis of Fe, Pd, and Fe–Pd bimetallic nanoparticles and their application as recyclable catalysts for [3 + 2] cycloaddition reaction: a comparative approach

The Fe–Pd bimetallic nanoparticles exhibit strong catalytic activity compared to their respective monometallic nanoparticles.

Magnetically separable core–shell iron oxide@nickel nanoparticles as high-performance recyclable catalysts for chemoselective reduction of nitroaromatics

A magnetically separable core–shell iron oxide@nickel nanocatalyst was synthesized, characterized and applied for the aromatic nitro group reduction.

Encrustation of cobalt doped copper ferrite nanoparticles on solid scaffold CNTs and their comparison with corresponding ferrite nanoparticles: a study of structural, optical, magnetic and photo catalytic properties

Co_xCu_1−xFe₂O₄ nanoparticles and their structural, optical, magnetic and catalytic comparison with CNTs encrusted Co_xCu_1−xFe₂O₄ nanocomposites.

Palladium encapsulated within magnetic hollow mesoporous TiO2 spheres (Pd/Fe3O4@hTiO2) as a highly efficient and recyclable catalysts for hydrodechlorination of chlorophenols

Herein, we introduced a method to encapsulate Pd(0) within TiO₂ hollow mesoporous nanostructures.

Magnetic nanoparticles supported oxime palladacycle as a highly efficient and separable catalyst for room temperature Suzuki–Miyaura coupling reaction in aqueous media

Magnetic nanoparticles of Fe₃O₄ supported oxime palladacycle as a novel catalyst for room temperature Suzuki coupling reaction in aqueous media.

Preparation and catalytic applications of nanomaterials: a review

The present review systematically summarizes the synthesis and specific catalytic applications of nanomaterials such as MSN, nanoparticles, LD hydroxides, nanobubbles, quantum dots,etc.

Excellent catalytic activity of magnetically recoverable Fe3O4–graphene oxide nanocomposites prepared by a simple method

An easy-to-prepare Fe₃O₄–graphene oxide nanocomposite which works well as a reusable catalyst for A³-coupling reactions.

Sulfonic acid-functionalized magnetic nanoparticles as a recyclable and eco-friendly catalyst for atom economical Michael addition reactions and bis indolyl methane synthesis

Sulfonic acid-functionalized magnetic nanoparticles as a recyclable and eco-friendly catalyst for atom economical Michael addition reaction and bis indolyl methane synthesis.

Magnetic nano-Fe3O4@TiO2/Cu2O core–shell composite: an efficient novel catalyst for the regioselective synthesis of 1,2,3-triazoles using a click reaction

An efficient and recoverable core–shell nanomagnetic composite was developed for regioselective synthesis of 1,2,3-triazoles using a green procedure.

Clickable complexing agents: functional crown ethers for immobilisation onto polymers and magnetic nanoparticles

A modular library of crown ethers and monoazacrown ethers supported by CuAAC reactions onto magnetic nanoparticles and polymers has been prepared and evaluated as extracting materials for Pb²⁺ from aqueous and organic solutions.

Mechanochemical synthesis of advanced nanomaterials for catalytic applications

Mechanochemical synthesis emerged as the most advantageous, environmentally sound alternative to traditional routes for nanomaterials preparation with outstanding properties for advanced applications.

Surfactant-free Pd@pSiO2 yolk–shell nanocatalysts for selective oxidation of primary alcohols to aldehydes

The surfactant-free Pd@pSiO₂ yolk–shell nanoparticles proved to be an efficient catalyst for the oxidation of substituted benzyl alcohols.

Pd-grafted functionalized mesoporous MCM-41: a novel, green and heterogeneous nanocatalyst for the selective synthesis of phenols and anilines from aryl halides in water

The preparation of phenols and anilines from aryl halides in the presence of MCM-41-dtz-Pd as a heterogeneous nanocatalyst has been introduced.

Triazole-stabilized gold and related noble metal nanoparticles for 4-nitrophenol reduction

The preparation of N-substituted triazole–polyethylene glycol-stabilized metal nanoparticles and their high catalytic activities for 4-nitrophenol reduction.

Functionalizing with glycopeptide dendrimers significantly enhances the hydrophilicity of the magnetic nanoparticles

A novel hybrid magnetic nanoparticle coated with glycopeptide dendrimers was synthesized and utilized for highly efficient N-glycopeptide enrichment.

Hollow Co@C prepared from a Co-ZIF@microporous organic network: magnetic adsorbents for aromatic pollutants in water

ZIF-67 nanoparticles containing Co²⁺ ions were coated with a microporous organic network (MON). The thermolysis of ZIF-67@MON resulted in the formation of hollow Co@C materials which showed good performance as magnetic adsorbents for aromatic pollutants in water.

C(sp2)–C(sp2) cross coupling reaction catalyzed by a water-stable palladium complex supported onto nanomagnetite particles

A new palladium nanoparticles-based magnetic catalyst, which is stable in water, has been successfully synthesized, characterized and employed for the Suzuki reaction.

Magnetically retrievable magnetite (Fe3O4) immobilized ionic liquid: an efficient catalyst for the preparation of 1-carbamatoalkyl-2-naphthols

An efficient and greener protocol for the synthesis of 1-carbamatoalkyl-2-naphthols using magnetically retrievable ionic liquid.

Highly active thiol-functionalized SBA-15 supported palladium catalyst for Sonogashira and Suzuki–Miyaura cross-coupling reactions

SBA-15 supported heterogeneous Pd-catalyst was prepared and applied towards Sonogashira and Suzuki–Miyaura cross-coupling reactions of activated and inactivated aryl halides to give the corresponding coupling products in up to 98% yield.

Nonquenching of charge carriers by Fe3O4 core in Fe3O4/ZnO nanosheet photocatalyst

Fe3O4-implanted ZnO and pristine ZnO nanosheets have been synthesized hydrothermally. High-resolution scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, elemental mapping, selected area electron diffractometry, powder X-ray diffractometry, Raman spectroscopy, vibrating sample magnetometry, solid state impedance spectroscopy, UV-visible diffuse reflectance spectroscopy, and photoluminescence spectroscopy show implantation of Fe3O4 in ZnO nanosheets. Fe3O4 core with ZnO shell is of type I core/shell heterostructure which is to quench charge carriers and suppress photocatalysis. But the photocatalytic activity is not suppressed on implantation of Fe3O4 in ZnO nanosheets, and time controlled single photon counting lifetime spectroscopy shows that the photogenerated charge carriers are not quenched by the Fe3O4 core in the ZnO nanosheets. The composite nanosheets are photostable, reusable, and magnetically recoverable, revealing potential application in mineralization of organic pollutants.

In situ synthesis of silver supported nanoporous iron oxide microbox hybrids from metal-organic frameworks and their catalytic application in p-nitrophenol reduction

Ag nanoparticles (NPs) are successfully grown in situ on nanoporous Fe2O3 microboxes (Ag/Fe2O3) simply by annealing Prussian blue (PB) in the presence of silver nitrate for the first time. The catalytic activity of the Ag/Fe2O3 microboxes for the reduction of p-nitrophenol (PNP) with NaBH4 is measured by UV-vis spectroscopy. It is found that the composites exhibit bifunctional properties with high magnetization and excellent catalytic activity toward PNP reduction. The high catalytic activity of the catalyst might be attributed to its high surface area and the synergistic effect on the delivery of electrons between Ag NPs and Fe2O3 microboxes. In addition, efficient reduction is observed and found to depend upon the content of Ag in the Ag/Fe2O3 microboxes. The dosage of the catalyst and the reaction temperature were investigated. Furthermore, the catalysts can be easily recycled by applying an external magnetic field while maintaining the catalytic activity without significant decrease even after running six times. The unique properties provide an ideal platform to study various metal/Fe2O3 catalysts which can be potentially applied in a wide variety of fields of catalysis and green chemistry.