Colloidal calcium nanoparticles: digestive ripening in the presence of a capping agent and coalescence of particles under an electron beam

Sanyal, Udishnu; Datta, Ranjan; Jagirdar, Balaji R.

doi:10.1039/c1ra00468a

Cited by 18 publications

(10 citation statements)

References 20 publications

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“…In a very recent work, we reported the synthesis of calcium nanoparticles by the SMAD method. 21 The synthesis of calcium nanoparticles by conventional methods turned out to be a difficult task because of its high reactivity and pyrophoric nature. In our work, the as-prepared, nearly spherical nanoparicles were free standing but quite polydisperse in nature with an average particle size of 8.3 ± 1.0 nm.…”

Section: The Issue Of Size Control: Digestive Ripeningmentioning

confidence: 99%

Digestive ripening: a synthetic method par excellence for core–shell, alloy, and composite nanostructured materials

Bhaskar

Jagirdar

2012

J Chem Sci

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The solvated metal atom dispersion (SMAD) method has been used for the synthesis of colloids of metal nanoparticles. It is a top-down approach involving condensation of metal atoms in low temperature solvent matrices in a SMAD reactor maintained at 77 K. Warming of the matrix results in a slurry of metal atoms that interact with one another to form particles that grow in size. The organic solvent solvates the particles and acts as a weak capping agent to halt/slow down the growth process to a certain extent. This as-prepared colloid consists of metal nanoparticles that are quite polydisperse. In a process termed as digestive ripening, addition of a capping agent to the as-prepared colloid which is polydisperse renders it highly monodisperse either under ambient or thermal conditions. In this, as yet not well-understood process, smaller particles grow and the larger ones diminish in size until the system attains uniformity in size and a dynamic equilibrium is established. Using the SMAD method in combination with digestive ripening process, highly monodisperse metal, core-shell, alloy, and composite nanoparticles have been synthesized. This article is a review of our contributions together with some literature reports on this methodology to realize various nanostructured materials.

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Section: The Issue Of Size Control: Digestive Ripeningmentioning

confidence: 99%

Digestive ripening: a synthetic method par excellence for core–shell, alloy, and composite nanostructured materials

Bhaskar

Jagirdar

2012

J Chem Sci

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“…19 It involves solvation of metal atoms in a low temperature organic solvent matrix which upon warm up to room temperature leads to the process of nucleation and growth. In the past, nanoparticles of various metals, such as Cu, 20 Ag, 21 Au, 22 Zn, 20 Pd, 23 Ca, 24 Al, 25 and Mg, 26 have been obtained by the SMAD method. By a combination of SMAD and the digestive ripening process 27 which transforms colloids consisting of polydisperse nanoparticles into colloids comprising highly monodisperse nanoparticles, highly stable colloids of these metals were obtained.…”

Section: Introductionmentioning

confidence: 99%

Carbonization of solvent and capping agent based enhancement in the stabilization of cobalt nanoparticles and their magnetic study

Arora

Jagirdar

2012

J. Mater. Chem.

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We describe a hybrid synthetic protocol, the solvated metal atom dispersion (SMAD) method, for the synthesis and stabilization of monodisperse amorphous cobalt nanoparticles. By employing an optimized ratio of a weakly coordinating solvent and a capping agent monodisperse colloidal cobalt nanoparticles (2 AE 0.5 nm) have been prepared by the SMAD method. However, the as-prepared samples were found to be oxidatively unstable which was elucidated by their magnetic studies. Oxidative stability in our case was achieved via a pyrolysis process that led to the decomposition of the organic solvent and the capping agent resulting in the formation of carbon encapsulated cobalt nanoparticles which was confirmed by Raman spectroscopy. Controlled annealing at different temperatures led to the phase transformation of metallic cobalt from the hcp to fcc phase. The magnetic behaviour varies with the phase and the particle size; especially, the coercivity of nanoparticles exhibited strong dependence on the phase transformation of cobalt. The high saturation magnetization close to that of the bulk value was achieved in the case of the annealed samples. In addition to detailed structural and morphological characterization, the results of thermal and magnetic studies are also presented.

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Section: 金属纳米粒子的制备unclassified

“…通常采用长链烷基硫醇、有机胺、有机酸以及聚合物硫醇等强配体作为消化熟化剂制备单分散金属纳米粒子, 包括 Au [28,35,46,68,72] 、Ag [21,73～76] 、Cu [77] 、Co [47,78] 、 Ca [79] 、Mg [80] 、In [81] 、Pd [20,82～84] 及 Pt、Ru、Rh [61] [85] . 此外, 以十六烷基胺作保护剂对多分散钙纳米粒子在室温下搅拌处理, 可以得到直径为 2～3 nm 的单分散钙纳米粒子 [79] ; 类似地, 在室温下处理四氢呋喃溶剂化的镁粒子的多分散体系可以获得尺寸为(2.8±0.2) nm 的均一镁纳米粒子 [80] . [85] Figure 7 TEM images of silver nanoparticles before digestive ripening (a), after digestion (b) and after ripening (c) 另外, 金属纳米粒子与大量的强配体作用, 可以形成金属原子与配体的配合物, 也可以形成硫醇保护的金属原子簇 [86] .…”

Section: 金属纳米粒子的制备unclassified

Digestive Ripening at Nanoscale and Its Application in the Preparation of Monodisperse Nanomaterials

Li¹,

Gao²,

Zhang³

et al. 2019

Acta Chim. Sinica

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Recently, a digestive ripening process at nanoscale has been widely used to prepare monodisperse nanoparticles (NPs), especially for sub-10 nm small NPs, with significant advantages such as the very narrow size distribution of the obtained nanoparticles, the versatile applications for various nanoparticles and the simple operation process. However, no Chinese references are reported on digestive ripening process till now, which may limit the cognition and utility of digestive ripening method for some domestic scientists. Thus, this review starts from the discovery of the phenomenon and the proposal of mechanism for digestive ripening at nanoscale, to the analysis of influence factors including the precursor in the precipitation reaction, the digestive ripening reagent, heating treatment temperature and processing time, solvent media and so on. Then, theoretical hypothesis and the derived results are introduced based on the charged surface, the curvature effect, the interaction between NP surface and attached ligand layer, the diffusion effect and the competing reaction balance in the digestive ripening process. Subsequently, the important applications of digestive ripening method in the preparation of monodisperse nanomaterials of metal NPs, alloy NPs, quantum dots of metal oxide and metal chalcogenide, and other NPs are discussed, the obtained small metal or alloy NPs show a perfect sphere shape and a very narrow size distribution (relative standard deviation less than ±5%). Finally, the broad perspectives are proposed in the NP assembly for optical, electric and magnetic nanodevices, and the heterogeneous catalysis of monodisperse metal, alloy and semiconducotr NPs via the digestive ripening method.

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Colloidal calcium nanoparticles: digestive ripening in the presence of a capping agent and coalescence of particles under an electron beam

Cited by 18 publications

References 20 publications

Digestive ripening: a synthetic method par excellence for core–shell, alloy, and composite nanostructured materials

Digestive ripening: a synthetic method par excellence for core–shell, alloy, and composite nanostructured materials

Carbonization of solvent and capping agent based enhancement in the stabilization of cobalt nanoparticles and their magnetic study

Digestive Ripening at Nanoscale and Its Application in the Preparation of Monodisperse Nanomaterials

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