Superparamagnetic High-Magnetization Microspheres with an Fe3O4@SiO2 Core and Perpendicularly Aligned Mesoporous SiO2 Shell for Removal of Microcystins

Deng, Yonghui; Qi, Dawei; Deng, Chunhui; Zhang, Xiangming; Zhao, Dongyuan

doi:10.1021/ja0777584

Cited by 1,621 publications

(856 citation statements)

References 17 publications

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“…24 By controlling the TEOS concentration, pH, and coating time, the thickness of the SiO 2 coating and therefore the void space size can be easily controlled ( Figure S3, Supporting Information). 25,26 The SiNPs utilized for this study have an average diameter around 100 nm. Smaller particles might yield better battery performance, but they are more costly as well.…”

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confidence: 99%

A Yolk-Shell Design for Stabilized and Scalable Li-Ion Battery Alloy Anodes

Liu¹,

Wu²,

McDowell³

et al. 2012

Nano Lett.

1,654

1,437

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Silicon is regarded as one of the most promising anode materials for next generation lithium-ion batteries. For use in practical applications, a Si electrode must have high capacity, long cycle life, high efficiency, and the fabrication must be industrially scalable. Here, we design and fabricate a yolk-shell structure to meet all these needs. The fabrication is carried out without special equipment and mostly at room temperature. Commercially available Si nanoparticles are completely sealed inside conformal, thin, self-supporting carbon shells, with rationally designed void space in between the particles and the shell. The well-defined void space allows the Si particles to expand freely without breaking the outer carbon shell, therefore stabilizing the solid-electrolyte interphase on the shell surface. High capacity (∼2800 mAh/g at C/10), long cycle life (1000 cycles with 74% capacity retention), and high Coulombic efficiency (99.84%) have been realized in this yolk-shell structured Si electrode. KEYWORDS: Silicon nanoparticle, Li-ion battery, anode, yolk-shell, solid-electrolyte interphase, in situ TEM E lectrochemical energy storage has become a critical technology for a variety of applications, including grid storage, electric vehicles, and portable electronic devices. The lithium-ion battery (LIB) is an attractive energy storage device because of its relatively high energy density and good rate capability. To further increase the energy density for more demanding applications, however, new electrode materials with higher specific and volumetric capacity are required. Since the initial commercialization of the LIB two decades ago, there has been little progress in commercializing new electrode materials with significantly higher capacity. 1 To meet the increasing demand for energy storage capability, novel electrode materials with higher capacity, low cost, and the ability to be produced at large scale are of great interest.Alloy-type anodes (Si, Ge, Sn, Al, Sb, etc.) have much higher Li storage capacity than the intercalation-type graphite anode that is currently used in Li-ion batteries. 2 Among all the alloy anodes, silicon has the highest specific capacity: Experiments have demonstrated an initial specific capacity of >3500 mAh/g, which is 10 times the capacity of graphite. 3 In addition, silicon is the second most abundant element in the earth's crust (28% by mass), indicating its potential to be utilized in large quantities at low cost. 4 A further benefit is that mass production of elemental silicon is already a mature technology in the semiconductor industry. Despite these advantages, graphite anodes still dominate the marketplace due to the fact that alloy anodes have two major challenges that have prevented their widespread use. First, alloy anodes undergo significant volume expansion and contraction during Li insertion/extraction. 2 This volume change (∼300% for Si) can result in pulverization of the initial particle morphology and causes the loss of electrical contact between active mat...

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mentioning

confidence: 99%

A Yolk-Shell Design for Stabilized and Scalable Li-Ion Battery Alloy Anodes

Liu¹,

Wu²,

McDowell³

et al. 2012

Nano Lett.

1,654

1,437

View full text Add to dashboard Cite

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“…S5) [25]. But the intensity of these characteristic diffraction peaks are weakened because of the shielding effect of the C 18 -modified mesoporous silica shell and the diffraction peak of amorphous mesoporous silica appears at 2h of 23°.…”

Section: Characteristics Of Fe 3 O 4 /Msio 2 -C 18 Magnetic Compositementioning

confidence: 99%

“…Before measurement, the samples were degassed in a vacuum at 300°C for at least 6 h. Brunauer-Emmett-Teller (BET) method was used to obtain the specific surface area with the adsorption data in a relative pressure range (P/P 0 ) of 0.05-1.0. By using the Barrett-Joyner-Halenda (BJH) model, the pore volume and pore size distribution were achieved from the adsorption branch of isotherm and the total pore volume (V t ) was estimated from the adsorbed amount at a relative pressure of 0.98 [25]. Low-angle X-ray diffraction (XRD) measurements were performed with a PANalytical X'pert Pro diffractometer (PANalytical, Almelo, the Netherlands), using a monochromatized X-ray beam with nickel-filtered Cu Ka radiation.…”

Section: Materials Characterizationmentioning

confidence: 99%

“…A continuous scan mode was used to collect 2h data from 0.5°to 9.0°with a 0.4°min À1 scan rate. Wide-angle XRD datas were also collected from 10.0°to 90°with a scan rate of 4°min À1 [25]. The vibrating sample magnetization (VSM) curves of the magnetic materials were analyzed with an LDJ9600 magnetometer (LDJ Electronics, Troy, MI) by changing H between +10,000 and À10,000 Oe at 25°C.…”

Section: Materials Characterizationmentioning

confidence: 99%

“…Zhao reported the preparation of Fe 3 O 4 /nSiO 2 /mSiO 2 magnetic mesoporous silica microspheres for the adsorption of microcystin from water solution [25]. Based on it, magnetic mesoporous silica composites modified with different functional groups were synthesized for the adsorption removal of environmental pollutants [26][27][28][29][30][31][32] or extraction of trace hydrophobic organic pollutants [33,34] from aqueous matrix.…”

Section: Introductionmentioning

confidence: 99%

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One-pot synthesis of C18-functionalized core–shell magnetic mesoporous silica composite as efficient sorbent for organic dye

Zhang

Zeng

Wang

et al. 2015

Journal of Colloid and Interface Science

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a b s t r a c tIn this work, a facile one-pot strategy was proposed for the synthesis of C 18 -functionalized core-shell magnetic mesoporous silica composite (Fe 3 O 4 /mSiO 2 -C 18 ). The Fe 3 O 4 /mSiO 2 -C 18 composite, with an average size of 80 nm and a functionalized mesoporous silica shell of about 30 nm in thickness, has excellent adsorption ability toward methylene blue dye (MB) due to the large surface area (303 m 2 g À1 ) and the abundant hydrophobic C 18 groups. The adsorption equilibrium was achieved within 20 min and the adsorption behavior of MB on Fe 3 O 4 /mSiO 2 -C 18 composite fitted the pseudo-second-order kinetic model well (k 2 = 1.29 Â 10 À2 g mg À1 min À1 , q e = 144.72 mg g À1 , h o = 270.27 mg g À1 min À1 under 25°C and an initial MB concentration of 10 mg L À1 ). Langmuir and Freundlich isothermal adsorption models can both be used to describe the adsorption process and the maximum Langmuir adsorption capacity of MB on Fe 3 O 4 /mSiO 2 -C 18 at 25°C and pH 7.5 is 363.64 mg g À1 . Thermodynamic parameters show that the adsorption reaction is exothermic and spontaneous (DH 0 = À63.49 kJ mol À1 , DG 0 = À7.80 kJ mol À1 ). Ionic strength and pH affected the adsorption slightly. In addition, the MB adsorbed sorbent can be readily separated from water solution by an external magnet because of the high magnetic saturation value (22.62 emu g À1 ). After being regenerated by treatment with acidic methanol, the sorbent could be reused for at least 5 cycles with a little decrease in adsorption capacity.

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MRI Contrast Agents Based on Inorganic Nanoparticles

Na¹,

Hyeon²

2011

Nanoplatform‐Based Molecular Imaging

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INTRODUCTIONMagnetic resonance imaging (MRI) is currently one of the most powerful diagnosis tools in medical science [1]. MRI produces images through monitoring the relaxation processes of water protons under a magnetic field. With this technique, it is possible to obtain realtime images of the internal anatomy and physiology of living organisms in a noninvasive manner. Since it can give anatomic images of soft tissue with high resolution, it has been the preferred tool for imaging the brain and the central nervous system, for assessing cardiac function, and for detecting tumors. Although MRI itself gives detailed images, making a diagnosis based purely on the resulting images may not be accurate since normal tissues and lesions often show small differences in relaxation time. There are several strategies to obtain high-resolution MR images such as the use of high magnetic field and the design of coil systems. In economical and practical terms, it is more feasible to develop supplements that can maximize the ability of imaging tools. One of the most effective supplements is a chemical compound known as a contrast agent that is introduced to a living body for the improvement of visibility in the image. In particular, biological and functional information can be obtained in image form as a result of the interrelation of the contrast agent and the biological system. Therefore a MRI contrast agent is an essential research field in biological and medical sciences to supply a vision for the analysis of biological information and the diagnosis of diseases.Most of the presently available MRI contrast agents are paramagnetic complexes, usually gadolinium (Gd 3+ ) chelates [2]. Among them, Gd-DTPA has been the most widely used. Its main clinical applications are focused on detecting the breakage of the blood-brain barrier (BBB) and on changes in vascularity, flow dynamics, and perfusion. Twenty years ago, a different class of contrast agent, superparamagnetic iron oxide (SPIO), was developed, and it has received great attention as a liver contrasting agent [3]. It was the first nanoparticulate MRI contrast agent and is still used clinically. Gd-based contrast agents Nanoplatform-Based Molecular Imaging Edited by Xiaoyuan Chen

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Superparamagnetic High-Magnetization Microspheres with an Fe₃O₄@SiO₂ Core and Perpendicularly Aligned Mesoporous SiO₂ Shell for Removal of Microcystins

Cited by 1,621 publications

References 17 publications

A Yolk-Shell Design for Stabilized and Scalable Li-Ion Battery Alloy Anodes

A Yolk-Shell Design for Stabilized and Scalable Li-Ion Battery Alloy Anodes

One-pot synthesis of C18-functionalized core–shell magnetic mesoporous silica composite as efficient sorbent for organic dye

MRI Contrast Agents Based on Inorganic Nanoparticles

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