CoFe2O4–ZnS nanocomposite: a magnetically recyclable photocatalyst

Senapati, Kula Kamal; Borgohain, C.; Phukan, Prodeep

doi:10.1039/c2cy20400b

Cited by 91 publications

(64 citation statements)

References 42 publications

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“…In particular, optomagnetic nanocomposites have attracted attention in recent years due to their multifunctional properties, thereby expanding their use in photocatalyis and biomedical application such as multimodal fluorescence imaging, magnetic resonance imaging (MRI), magnetic separation and drug targeting [7][8][9]. More specifically, magnetic nanoparticles (MNPs) combined with QDs have been developed into specific functionalized luminescent magnetic nanocomposites (LMNs), which have the advantages of both MNPs and QDs [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Self-organization of an optomagnetic CoFe₂O₄–ZnS nanocomposite: preparation and characterization

et al. 2015

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We report an advanced method for the self-organization of an optomagnetic nanocomposite composed of both fluorescent clusters (ZnS quantum dots, QDs) and magnetic nanoparticles (CoFe2O4). ZnS nanocrystals were prepared via an aqueous method at different temperatures (25, 50, 75, and 100 °C). Their structural, optical and chemical properties were comprehensively characterized by X-ray diffraction (XRD), UV-Vis, photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), transmission electron microscopy (TEM), and infrared spectroscopy (FT-IR). The highest PL intensity was observed for the cubic ZnS nanoparticles synthesized at 75 °C which were then stabilized electrosterically using thioglycolic acid. The photophysical analysis of the capped QDs with particle size in the range 9-25 nm revealed that the emission intensity increases and the optical band gap rises compared to uncapped nanocrystals (3.88 to 4.02 eV). These band gaps are both wider than that of bulk ZnS resulting from the quantum confinement effect. Magnetic nanoparticles were synthesized via a coprecipitation route and a sol-gel process was used to form the functionalized, silica-coated CoFe2O4. Finally, thiol coordination was used for binding the QDs to the surface of the magnetic nanoparticles. The fluorescence intensity and magnetic properties of the nanocomposites are related to the ratio of ZnS and CoFe2O4. As-prepared optomagnetic nanocomposite with small size (12-45 nm), acceptable saturation magnetization (about 6.7 emu/g), and satisfactory luminescent characteristics could be successfully prepared. These are promising candidates for biological and photocatalytic applications.

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Section: Introductionmentioning

confidence: 99%

Self-organization of an optomagnetic CoFe₂O₄–ZnS nanocomposite: preparation and characterization

et al. 2015

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“…It may be attested due to sharper and pronounced peaks when compared with the as-synthesized and not calcined sample (Figures 4a and 4b). 36,37 No other patterns were found on the CoFe 2 O 4 sample, which demonstrate the efficiency of the co-precipitation method of synthesis. The as-synthesized SrO sample was also analyzed by FTIR.…”

Section: Resultsmentioning

confidence: 94%

“…Matching the bands of the as-synthesized ferrite with the SrO immobilized sample, small displacements are observed; they are ascribed to polarity increasing of metal-oxygen bonds. 37,40 All the information here described is important for the catalytic activity explanations, as seem ahead.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization and Catalytic Evaluation of Magnetically Recoverable SrO/CoFe2O4 Nanocatalyst for Biodiesel Production from Babassu Oil Transesterification

Falcão¹,

Garcia²,

Moura³

et al. 2017

J. Braz. Chem. Soc.

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Biodiesel production has gained a lot of attention due to its environmental benefits and production from renewable sources. Here, it is reported a magnetically recoverable catalyst of SrO immobilized on a CoFe 2 O 4 support (SrO/CoFe 2 O 4 ), which was efficiently applied for babassu oil transesterification and used up to four cycles without a significant activity loss. The stability and performance of the catalyst were analyzed considering the solvent used for its synthesis. Characterizations such as vibrating sample magnetometer (VSM), thermogravimetry (TG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were performed. The present study demonstrated that the catalyst has a strong magnetic response, which reflects the nature of the nanoparticles. For the first run, the material presented a yield of 96% when synthesized in acetone in a molar proportion of SrO/CoFe 2 O 4 of 5:1.

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“…Highly stable CoFe 2 O 4 nanoparticles were synthesized as a magnetically separable heterogeneous catalyst for the Knoevenagel condensation of aldehydes with ethyl cyanoacetates in water solvent [45]. The CoFe 2 O 4 nanoparticles were stable during the reaction, and the particles were therefore recyclable.…”

Section: New Catalytic Systemsmentioning

confidence: 99%

Mechanistic Studies of Solid Acids and Base‐Catalyzed Clean Technologies

Takagaki

Nishimura

Ebitani

2013

Heterogeneous Catalysts for Clean Technology

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IntroductionThe importance of solid acid and base catalysts in clean technologies has been recognized for a long time, and many books and reviews have been published since the text by Tanabe [1]. Tanabe et al.[2] revised their book in 1989, reviewing the definition and classification of solid acids and bases, determination of acidic and basic properties, and catalysis for isomerization, acylation, hydration of alkenes, methanol conversion, dehydration, dehydrogenation, esterification, hydrolysis, hydrocraking (hydrogenolysis), and oxidation reactions. The development of solid acid catalysts has been surveyed in several reviews [3][4][5][6][7][8][9][10]. Catalysis by solid bases and the mechanism of base-catalyzed reactions such as isomerization of alkenes and alkynes, aldol addition and aldol condensation, Henry reaction (nitro-aldol reaction), Knoevenagel condensation, Michael addition, the Tishchenko reaction, alkylation reactions, and addition reactions such as addition of amines to epoxides, transfer hydrogenation (Meerwein-Ponndorf-Verley (MPV) reaction), esterification and transesterification, and liquid-phase oxidations including Baeyer-Villiger oxidation and alkene epoxidation have been recently emphasized by Ono and Hattori [11], encompassing many splendid reviews and papers [12][13][14][15][16][17][18][19][20].The first part of this chapter is intended to survey recent literature on new catalytic materials because the development of new types of metal oxides and layered-and carbon-based materials with different morphologies opens up novel acid-base catalysis that enables new type of clean reaction technologies. Mechanistic considerations of acid-and base-catalyzed reactions should result in new clean catalytic processes for Green and Sustainable Chemistry, for example, transformations of biorenewable feedstock into value-added chemicals and fuels [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. The latter part of this chapter, therefore, focuses on biomass conversion using solid acid and base catalysts, which covers recent developments on acid-base, one-pot reaction systems for carbon-carbon bond formations, and biomass conversion including synthesis of furfurals from sugars, biodiesel production, and glycerol utilization.

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CoFe2O4–ZnS nanocomposite: a magnetically recyclable photocatalyst

Cited by 91 publications

References 42 publications

Self-organization of an optomagnetic CoFe₂O₄–ZnS nanocomposite: preparation and characterization

Self-organization of an optomagnetic CoFe₂O₄–ZnS nanocomposite: preparation and characterization

Synthesis, Characterization and Catalytic Evaluation of Magnetically Recoverable SrO/CoFe2O4 Nanocatalyst for Biodiesel Production from Babassu Oil Transesterification

Mechanistic Studies of Solid Acids and Base‐Catalyzed Clean Technologies

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CoFe2O4–ZnS nanocomposite: a magnetically recyclable photocatalyst

Cited by 91 publications

References 42 publications

Self-organization of an optomagnetic CoFe2O4–ZnS nanocomposite: preparation and characterization

Self-organization of an optomagnetic CoFe2O4–ZnS nanocomposite: preparation and characterization

Synthesis, Characterization and Catalytic Evaluation of Magnetically Recoverable SrO/CoFe2O4 Nanocatalyst for Biodiesel Production from Babassu Oil Transesterification

Mechanistic Studies of Solid Acids and Base‐Catalyzed Clean Technologies

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Self-organization of an optomagnetic CoFe₂O₄–ZnS nanocomposite: preparation and characterization

Self-organization of an optomagnetic CoFe₂O₄–ZnS nanocomposite: preparation and characterization