The surface chemistry of iron oxide nanocrystals: surface reduction of γ-Fe2O3 to Fe3O4 by redox-active catechol surface ligands

Daniel, Phillip; Shylin, Sergii I.; Lu, Hao; Tahir, Muhammad Nawaz; Panthöfer, Martin; Weidner, Tobias; Möller, Angela; Ksenofontov, Vadim; Tremel, Wolfgang

doi:10.1039/c7tc04795a

Cited by 19 publications

(21 citation statements)

References 51 publications

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“…Also, post-synthesis surface-functionalization can affect phase distribution, as demonstrated by Daniel and co-workers [60]. The replacement of oleic acid by catechol surface ligands led to the separation into two distinctive magnetic entities, due to reduction of a nanoparticle surface fraction to magnetite, which reduced the anisotropy constant and, consequently, the effective magnetization [60].…”

Section: Synthesis Of Shape Anisotropic Nanoparticlesmentioning

confidence: 99%

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Andrade

Veloso

Castanheira

2020

IJMS

121

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Research on iron oxide-based magnetic nanoparticles and their clinical use has been, so far, mainly focused on the spherical shape. However, efforts have been made to develop synthetic routes that produce different anisotropic shapes not only in magnetite nanoparticles, but also in other ferrites, as their magnetic behavior and biological activity can be improved by controlling the shape. Ferrite nanoparticles show several properties that arise from finite-size and surface effects, like high magnetization and superparamagnetism, which make them interesting for use in nanomedicine. Herein, we show recent developments on the synthesis of anisotropic ferrite nanoparticles and the importance of shape-dependent properties for biomedical applications, such as magnetic drug delivery, magnetic hyperthermia and magnetic resonance imaging. A brief discussion on toxicity of iron oxide nanoparticles is also included.

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Section: Synthesis Of Shape Anisotropic Nanoparticlesmentioning

confidence: 99%

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Andrade

Veloso

Castanheira

2020

IJMS

121

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“…10 When Fe 3 O 4 and γ-Fe 2 O 3 coexist, they will exhibit better stability, magnetic properties, and catalytic properties. 11 However, one extremely important point cannot be ignored that the efficiency of mono iron oxides at low temperature (<300 °C) is not high. 11,12 Catalysts that contain CuO species have been identified as active substances for the reduction of NO by CO. 12,13 However, it was found that single copper oxide still exhibited a lower NO reduction activity at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Mn-Modified CuO, CuFe₂O₄, and γ-Fe₂O₃ Three-Phase Strong Synergistic Coexistence Catalyst System for NO Reduction by CO with a Wider Active Window

Shi

Chu

Wang

et al. 2018

ACS Appl. Mater. Interfaces

106

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A series of samples with the precursor’s molar ratio of {KMn8O16}/{CuFe2O4} = 0, 0.008, 0.010, 0.016, and 0.020 were successfully synthesized for selective catalytic reduction of NO by CO. The physicochemical properties of all samples were studied in detail by combining the means of X-ray photoelectron spectroscopy, H2-temperature-programmed reduction, scanning electron microscopy mapping, X-ray diffraction (XRD), N2 physisorption (Brunauer–Emmett–Teller), NO + CO model reaction, and in situ Fourier transform infrared spectroscopy techniques. The results show that three phases of γ-Fe2O3, CuFe2O4, and CuO, which have strong synergistic interaction, coexist in this catalyst system, and different phases play a leading role in different temperature ranges. Mn species are highly dispersed in the three-phase coexisting system in the form of Mn2+, Mn3+, and Mn4+. Because of the strong interaction between Mn2+ and Fe species, a small amount of Cu2+ precipitates from CuFe2O4 and grows along the CuO(110) plane, which has better catalytic performance. Mn3+ can inhibit the conversion of γ-Fe2O3 to α-Fe2O3 at high temperature and then increases the high-temperature activity. The synergistic effect between Mn4+ and the surfaces of three phases generates active oxygen species Cu2+–O–Mn4+ and Mn4+–O–Fe3+, which can be more easily reduced to some synergistic oxygen vacancies during the reaction. Furthermore, the formed synergistic oxygen vacancies can promote the dissociation of NO and are also propitious to the transfer of oxygen species. All of these factors make the appropriate manganese-modified three-phase coexisting system have better catalytic activity than the manganese-free catalyst, making NO conversion rate reach 100% at around 250 °C and maintain to 1000 °C. Combining comprehensive analysis of various characterization results and in situ infrared as well as XRD results in the equilibrium state, a new possible NO + CO model reaction mechanism was temporarily proposed to further understand the catalytic processes.

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“…As shown in Figure a, ligand exchange with DHCA was verified by Fourier transform infrared (FTIR) spectroscopy . The magnetic nanoparticles covered with oleic acid showed strong CH 2 peaks at 2,921, 2,850, and 1,420 cm −1 before modification.…”

Section: Resultsmentioning

confidence: 85%

MnFe₂O₄ nanoclusters as labels for the quantitative detection of D‐dimer in a lateral‐flow immunochromatographic assay

Wang

Tang

et al. 2018

J Chinese Chemical Soc

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In this study, MnFe 2 O 4 nanoclusters were prepared as bioprobes to establish a lateral-flow immunochromatographic assay (LFIA) for the rapid and quantitative detection of D-dimer for the first time. The magnetic properties of the magnetic labels play a key role in the quantitative detection of biomolecules. The 47.3-nm MnFe 2 O 4 magnetic nanoclusters (MNCs) with good dispersion and high saturation magnetization (76 emu/g) were fabricated via thermal decomposition of Fe(acac) 3 with Mn(acac) 2 . The prepared MnFe 2 O 4 MNCs were well dispersed in water because the surfaces were fully covered with 3,4-dihydroxyhydrocinnamic acid (DHCA) molecules by ligand exchange. Anti-D-dimer antibodies were coupled on the surface of MnFe 2 O 4 MNCs, and the target protein, D-dimer, was detected, in the range 0.05-6 μg/mL. This assay provides a promising platform for D-dimer detection for point-of-care diagnosis.

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The surface chemistry of iron oxide nanocrystals: surface reduction of γ-Fe₂O₃ to Fe₃O₄ by redox-active catechol surface ligands

Abstract: The effect of surface functionalization on the structural and magnetic properties of catechol-functionalized iron oxide magnetic (γ-Fe2O3) nanocrystals was investigated.

Cited by 19 publications

References 51 publications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Mn-Modified CuO, CuFe₂O₄, and γ-Fe₂O₃ Three-Phase Strong Synergistic Coexistence Catalyst System for NO Reduction by CO with a Wider Active Window

MnFe₂O₄ nanoclusters as labels for the quantitative detection of D‐dimer in a lateral‐flow immunochromatographic assay

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The surface chemistry of iron oxide nanocrystals: surface reduction of γ-Fe2O3 to Fe3O4 by redox-active catechol surface ligands

Abstract: The effect of surface functionalization on the structural and magnetic properties of catechol-functionalized iron oxide magnetic (γ-Fe2O3) nanocrystals was investigated.

Cited by 19 publications

References 51 publications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Mn-Modified CuO, CuFe2O4, and γ-Fe2O3 Three-Phase Strong Synergistic Coexistence Catalyst System for NO Reduction by CO with a Wider Active Window

MnFe2O4 nanoclusters as labels for the quantitative detection of D‐dimer in a lateral‐flow immunochromatographic assay

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The surface chemistry of iron oxide nanocrystals: surface reduction of γ-Fe₂O₃ to Fe₃O₄ by redox-active catechol surface ligands

Mn-Modified CuO, CuFe₂O₄, and γ-Fe₂O₃ Three-Phase Strong Synergistic Coexistence Catalyst System for NO Reduction by CO with a Wider Active Window

MnFe₂O₄ nanoclusters as labels for the quantitative detection of D‐dimer in a lateral‐flow immunochromatographic assay