Features of the evolution of the structure and morphology of the surface of icosahedral copper particles in the annealing process

Vikarchuk, A. A.; Dorogov, M. V.

doi:10.1134/s0021364013100111

Cited by 11 publications

(10 citation statements)

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“…Described features of the internal structure and stresses aect the behaviour of ISPs in the temperature elds [6] and in the chemical environment [7].…”

Section: Resultsmentioning

confidence: 99%

New Functional Materials Based on Nano- and Micro-Objects with Developed Surface

et al. 2015

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The paper describes the materials with a developed surface fabricated on the basis of electrodeposited copper icosahedral small particles and coatings made of such particles. Increasing the specic surface area of the electrolytic metal is achieved by special heat and/or chemical treatments. Changes in the structure and morphology of icosahedral small particles are analyzed with scanning electron microscopy and X-ray diraction. The specic surface area of the material is determined with low-temperature gas adsorption technique. Annealing of icosahedral small particles and coatings leads to the formation of the porous structure and a forest of whiskers on their surface.Chemical etching of icosahedral small particles corrodes the inside material and provides the formation of hollow particles. Possible applications for obtained materials with a developed surface are oered.

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“…Described features of the internal structure and stresses aect the behaviour of ISPs in the temperature elds [6] and in the chemical environment [7].…”

Section: Resultsmentioning

confidence: 99%

New Functional Materials Based on Nano- and Micro-Objects with Developed Surface

et al. 2015

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“…The role of such an atmosphere in the production of nanowhiskers and nanopores on a particle's surface was analyzed in [2,[5][6][7]. The mechanism behind the formation of large internal cavities in ISPs remains unclear and warrants further study.…”

Section: Phase Transformations In Icosahedral Small Copper Particles mentioning

confidence: 99%

“…A great many papers focused on synthesizing, annealing, and inves tigating the properties of such particles have been pub lished [1][2][3][4][5][6][7][8][9]. It was shown in [1][2][3] that icosahedral particles contain high energy disclination defects that produce long range stress fields within the particles.…”

Section: Introductionmentioning

confidence: 99%

“…It was shown in [1][2][3] that icosahedral particles contain high energy disclination defects that produce long range stress fields within the particles. The authors of [4][5][6][7][8] studied the effect annealing has on the structural changes that occur within the parti cles (specifically, the growth of CuO nanowhiskers [3][4][5][6] and the emergence of nanopores on the surfaces of ISPs [7,8]). …”

Section: Introductionmentioning

confidence: 99%

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Phase transformations in icosahedral small copper particles during their annealing in different gas media

Priezzheva

Dorogov

Tyurkov

et al. 2015

Bull. Russ. Acad. Sci. Phys.

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“…However, such metallic icosahedra obtained from solvothermal methods all stay in the nanoscale. The annealing process and chemical vapor deposition can produce microscale icosahedral crystals, − while the angular mismatch aforementioned always exists, which may be overcome by filling in extra atoms in the gaps between the adjacent tetrahedra. Consequently, due to the inevitable angular mismatch, all these polyhedra formed by 20 (111) facets are not Platonic solids but can be called pseudo-icosahedra.…”

Section: Introductionmentioning

confidence: 99%

Dual-Step Reduction of Copper and Formation Mechanism of Cu Pseudo-Icosahedral Microcrystals

Sun

Zhou

2022

Crystal Growth & Design

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Pseudo-icosahedral Cu microcrystals have been synthesized in a solvothermal system containing CuSO 4 •5H 2 O as the precursor, polyvinylpyrrolidone (PVP) as a reductant/capping agent, and dimethylformamide as the solvent. The structural and morphological evolutions over the reaction time are investigated, which enable us to establish a novel formation mechanism of pseudo-icosahedral crystals of Cu. The first crystalline phase that appeared in the solution is Cu 4 SO 4 (OH) 6 •H 2 O in the form of microflakes. The microflakes are reduced and decomposed to Cu 2 O nanocrystallites, which assemble with PVP into spherulites. The Cu 2 O crystals are further reduced to Cu nanocrystallites, which aggregate with PVP again into spherical particles. An extraordinary phenomenon is that 20 separated (111) triangular plates form on each particle during surface recrystallization of Cu, and their locations match to the final facets of the pseudo-icosahedron. The plates extend to cover the whole surface of the sphere, forming a pseudo-icosahedral shell, followed by extension of the recrystallization from the surface to the core. This reversed crystal growth process increases the thickness of the plates until all the Cu nanocrystallites in the core are consumed. It is found that, during the surface recrystallization of polycrystalline spheres, the particles preferentially select the (111) planes of the face-centered cubic structure of Cu as the exposed faces because these planes have the minimum surface binding energy. The particles then try to keep as small as possible the specific surface area, and a pseudo-icosahedral shape consisting of 20 (111) plates, which has a specific surface area, about 10% lower than that of an octahedron, formed by eight (111) plates. Accordingly, the overall surface free energy of a pseudo-icosahedron is about 10% lower than that of an octahedron. The formation of tetrahedra as building units of icosahedra, as predicted previously, has not been observed. The formation of ideal icosahedra, the so-called perfect Platonic solid, and the formation of twin defects between neighboring (111) plates are not possible. The newly proposed formation mechanism of pseudo-icosahedra Cu sheds light on the understanding of formation of many other polyhedral crystals.

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Features of the evolution of the structure and morphology of the surface of icosahedral copper particles in the annealing process

Cited by 11 publications

References 3 publications

New Functional Materials Based on Nano- and Micro-Objects with Developed Surface

New Functional Materials Based on Nano- and Micro-Objects with Developed Surface

Phase transformations in icosahedral small copper particles during their annealing in different gas media

Dual-Step Reduction of Copper and Formation Mechanism of Cu Pseudo-Icosahedral Microcrystals

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