Highly stable carbon-protected cobalt nanoparticles and graphite shells

Lu, An Hui; Li, Wen Cui; Matoussevitch, Nina; Spliethoff, Bernd; Bönnemann, Helmut; Schüth, Ferdi

doi:10.1039/b414146f

Cited by 187 publications

(116 citation statements)

References 16 publications

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“…28 The formation of mesopores is attributed in part to carbon removal by in situ formed NZVI; the same catalytic reaction has been observed in an aerogel carbonization process. 25,29 Furthermore, the upward tendency at high relative pressure (P/P o = 0.95−1.00) results from the adsorption of the macropores and accumulation of carbon particles. In addition, the hysteresis loop of H3 showed nonlimiting adsorption at high relative pressure, suggesting the slit-shaped porous nature of the FHC composite.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Homogeneously Dispersed Zerovalent Iron Nanoparticles Supported on Hydrochar-Derived Porous Carbon: Simple, in Situ Synthesis and Use for Dechlorination of PCBs

Liu

Zhang

Hoekman

et al. 2016

ACS Sustainable Chem. Eng.

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Herein, we have developed a simple and effective strategy for in situ preparation of nanoscale zerovalent iron (NZVI) supported on porous carbon (PC) using renewable hydrochar as the carbon precursor. Physicochemical properties of the resultant NZVI/PC composites were characterized by XRD, SEM-EDS, TEM, and BET, and the effectiveness of these composites was evaluated for the remediation of PCBcontaminated water. Results showed that the iron ions were uniformly dispersed within the hydrochar matrix and serve as an activation agent for the hydrochar during a subsequent pyrolysis process. The iron is reduced in situ to NZVI with diameters of 8.5−10 nm, without requiring an additional reducing agent. At temperatures of 600−800°C, the well-dispersed NZVI catalyzes the transformation from amorphous carbon to graphitic carbon. The NZVI/PC composite prepared at 800°C exhibited high efficiency for adsorption and dechlorination of PCBs in aqueous solution. This is attributed to the composites' high surface area, uniformly dispersed nanoscale iron, high degrees of graphitic porous carbon, and substantial amount of mesopores. The present study offers a simple and sustainable approach for the preparation of prospective NZVI/PC with high stability and reactivity from renewable resources.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Homogeneously Dispersed Zerovalent Iron Nanoparticles Supported on Hydrochar-Derived Porous Carbon: Simple, in Situ Synthesis and Use for Dechlorination of PCBs

Liu

Zhang

Hoekman

et al. 2016

ACS Sustainable Chem. Eng.

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“…As a matter of fact, some core/shell nanoparticle systems, such as gold, silver, or iron oxide in graphitic shells prepared by PLAL or other methods in liquid have been reported in literatures. 16,[20][21][22] Almost with no exception, these systems were produced in aromatic liquid like toluene or benzonitrile, 16 while those nanoparticles prepared in hexane, a linear hydrocarbon, by laser ablation did not show any graphitic shell structure. 9,11 It can be deduced that the aromatic ring structure of the liquid is an essential condition to form the graphitic shells.…”

Section: -mentioning

confidence: 99%

Formation of core/shell structured cobalt/carbon nanoparticles by pulsed laser ablation in toluene

Kwong

Wong

Leung

et al. 2010

Journal of Applied Physics

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Magnetic cobalt nanoparticles encapsulated in shells of layered structure have been produced by the technique of pulsed laser ablation in toluene. The morphology, microstructure, and magnetic properties of the prepared nanoparticles were characterized by electron microscopy, micro-Raman spectroscopy, and superconducting quantum interference device magnetometry, respectively. The results indicated that the cobalt nanoparticles fabricated are noncrystalline but coated with the graphitic carbon layers. It is believed that the formation of these carbon layers well-protect the cobalt nanoparticles to be oxidized thus maintaining the superparamagnetic property. This is an important feature that makes the cobalt nanoparticles a useful material for medical and many other magnetic based applications.

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“…In our system, the magnetism was lost in 1 M HCl for both samples that were not heat-treated in N 2 at 973 K. In contrast, Co@carbon nanoparticles are stable in HNO 3 (53 wt%) for 2 months. 22 This indicates that the majority of the Co particles was protected by dense shells. Therefore, the acidtolerant properties of the Co@SiO 2 nanoparticles were attributed to the formation of a dense non-porous shell.…”

Section: Preparation Of Co@siomentioning

confidence: 98%

“…Therefore, the stability of the nanoparticles has been investigated in various atmospheres and liquids. [18][19][20][21][22][23][24][25][26][27] There are several examples of magnetic nanoparticles in aqueous solutions. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] For example in A@B particles, A components of magnetite (Fe 3 O 4 ), [27][28][29][30][31][32][33][34][35][36][37][38] maghemite (g-Fe 2 O 3 ) [39][40][41][42][43][44][45] and FePt, 46 and B c...…”

Section: 15-17mentioning

confidence: 99%

Chemically stable magnetic nanoparticles for metal adsorption and solid acid catalysis in aqueous media

et al. 2014

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We have developed a magnetically collectable, reusable adsorbent and a catalyst for concentrating heavy metal ions in acidic aqueous solutions and solid acid catalysis in aqueous media. Chemically stable, magnetic rattle-type core-shell particles, comprising metallic cobalt nanoparticles in hollow silica microspheres, were prepared by the sol-gel reaction of alkylsilyl trichlorides around water droplets in a water-in-oil emulsion. Sulfonic groups were immobilized on the external surface of the core-shell particles through silylation with 3-mercaptopropyl(trimethoxysilane) and subsequent oxidization of the thiol groups by nitric acid. The sulfonic groups acted as adsorption sites for Zn and Pb ions under acidic conditions and as catalytically active sites for the hydrolysis of ethyl acetate in aqueous media. The enclosed Co was not eroded during the regeneration of the adsorbent/catalyst by 1 M HCl. The chemical stability arose from the dense non-porous shell, which prevents the passage of solvents.

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Highly stable carbon-protected cobalt nanoparticles and graphite shells

Abstract: The fabrication of carbon-shell protected cobalt nanoparticles and hollow graphitic shells has been achieved via a pyrolysis process by using monodispersed cobalt nanoparticles as a template. These materials are mesoporous and highly stable under strong acidic and basic conditions.

Cited by 187 publications

References 16 publications

Homogeneously Dispersed Zerovalent Iron Nanoparticles Supported on Hydrochar-Derived Porous Carbon: Simple, in Situ Synthesis and Use for Dechlorination of PCBs

Homogeneously Dispersed Zerovalent Iron Nanoparticles Supported on Hydrochar-Derived Porous Carbon: Simple, in Situ Synthesis and Use for Dechlorination of PCBs

Formation of core/shell structured cobalt/carbon nanoparticles by pulsed laser ablation in toluene

Chemically stable magnetic nanoparticles for metal adsorption and solid acid catalysis in aqueous media

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