Tunable acid–base bifunctional catalytic activity of FeOOH in an orthogonal tandem reaction

Vernekar, Dnyanesh; Jagadeesan, Dinesh

doi:10.1039/c5cy00361j

Cited by 73 publications

(25 citation statements)

References 25 publications

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“…Iron oxide nanoparticles are available nowadays in a variety of shapes and are technologically important components widely used for the production of, e.g., magnetic materials [1,2,3], color pigments [4,5], catalysts [6], sorbents [7,8], for biomedical applications and drug delivery [3,9,10,11,12], as well as being key components in the Martial soil [13]. Very recently, iron oxides have become very popular as electrodes for lithium-ion, sodium-ion and alkaline-ion batteries [14,15,16,17,18].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Maghemite Nanoparticles with High Surface Area

2019

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Maghemite nanoparticles with high surface area were obtained from the dehydroxylation of lepidocrocite prismatic nanoparticles. The synthesis pathway from the precursor to the porous maghemite nanoparticles is inexpensive, simple and gives high surface area values for both lepidocrocite and maghemite. The obtained maghemite nanoparticles contained intraparticle and interparticle pores with a surface area ca. 30 × 103 m2/mol, with pore volumes in the order of 70 cm3/mol. Both the surface area and pore volume depended on the heating rate and annealing temperature, with the highest value near the transformation temperature (180–250 °C). Following the transformation, in situ X-ray diffraction (XRD) allowed us to observe the temporal decoupling of the decomposition of lepidocrocite and the growth of maghemite. The combination of high-angle annular dark-field imaging using scanning transmission electron microscopy (HAADF-STEM) and surface adsorption isotherms is a powerful approach for the characterization of nanomaterials with high surface area and porosity.

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Section: Introductionmentioning

confidence: 99%

Fabrication of Maghemite Nanoparticles with High Surface Area

2019

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“…Recently, much focus has been kept on Cubic Wustite (FeO, space group Fm3m), which under ambient conditions remains in metastable state and undergo oxidation to other polymorphic form of iron oxides [6,[79][80]. Like iron oxides, iron (III) oxyhydroxides also exists in various forms namely an orthorhombic goethite (α-FeOOH, space group Pnma), monoclinic akaganeite (β-FeOOH, space group I2/m), orthorhombic lepidocrocite (γ-FeOOH, space group Cmcm) and hexagonal feroxyhyte (δ-FeOOH) [81]. Ferrihydrite are another polymorphic form of iron (II) oxides that are relatively abundant in the natural systems and can be readily transformed into the goethite phase when there is a rapid oxidation process [82].…”

Section: Physicochemical Properties Of Iron Oxides 31 Crystallographi...mentioning

confidence: 99%

Iron Oxide Nanoparticles and Nano-Composites: An Efficient Tool for Cancer Theranostics

Jaison¹,

Mohan²

2022

Iron Oxide Nanoparticles

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In recent years, functional Iron oxides nanoparticles and nano-composites have gained a special traction in the field of nano-biomedicine, owing to their multifunctional capabilities that includes the inherent magnetic resonance imaging, magnetic bioseparation, cargo delivery and magnetic hyperthermia behavior. Interestingly, there are various forms of iron oxides available, with each form having their own specific characteristics. The different polymorphic forms of iron oxides are obtained through various synthetic routes and are usually surface modified to prevent their oxidation. The chapter shall encompass the synthesis and surface modification of Iron oxides nanoparticles, physicochemical properties, and theranostic application of the magnetic iron oxide nanoparticles in cancer. Also, the future directions of Iron oxide nanoparticles and nano-composites towards the achievement of clinically realizable nanoformulation for cancer theranostic applications were highlighted.

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“…9e, g) shows it to be most intense around the edges of the particle growing at low phosphate concentrations but concentrated at the ends of the nanorods grown under higher phosphate concentrations. The peak can be assigned to akaganéite [28][29][30], and its intensity map is interesting. On the particle synthesized under low phosphate conditions, where the aspect ratio of the rods is expected to be low, akaganéite has a high concentration around the edge of the rod, but, as Fig.…”

Section: Photo-induced Force Microscopy (Pifm)mentioning

confidence: 99%

The Role of Growth Directors in Controlling the Morphology of Hematite Nanorods

et al. 2020

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The control of the growth of hematite nanoparticles from iron chloride solutions under hydrothermal conditions in the presence of two different structure promoters has been studied using a range of both structural and spectroscopic techniques including the first report of photo induced force microscopy (PiFM) to map the topographic distribution of the structure-directing agents on the developing nanoparticles. We show that the shape of the nanoparticles can be controlled using the concentration of phosphate ions up to a limit determined to be~6 × 10 −3 mol. Akaganéite (β-FeOOH) is a major component of the nanoparticles formed in the absence of structure directors but only present in the very early stages (< 8 h) of particle growth when phosphate is present. The PiFM data suggest a correlation between the areas in which phosphate ions are adsorbed and areas where akaganéite persists on the surface. In contrast, goethite (α-FeOOH) is a directly observed precursor of the hematite nanorods when 1,2-diamino propane is present. The PiFM data shows goethite in the center of the developing particles consistent with a mechanism in which the iron hydroxide redissolves and precipitates at the nanorod ends as hematite.

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Tunable acid–base bifunctional catalytic activity of FeOOH in an orthogonal tandem reaction

Abstract: In this report, we have explored the acid–base bifunctional catalytic activity of iron oxohydroxides (FeOOH) by catalyzing deacetalization and Henry condensation reactions successively in a single pot.

Cited by 73 publications

References 25 publications

Fabrication of Maghemite Nanoparticles with High Surface Area

Fabrication of Maghemite Nanoparticles with High Surface Area

Iron Oxide Nanoparticles and Nano-Composites: An Efficient Tool for Cancer Theranostics

The Role of Growth Directors in Controlling the Morphology of Hematite Nanorods

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