Influence of Particle Size Distribution on Lifetime and Thermal Stability of Ostwald Ripening of Supported Particles

ChemCatChem ◽  
2018 ◽  
Vol 10 (13) ◽  
pp. 2900-2907 ◽  
Author(s):  
Sulei Hu ◽  
Wei-Xue Li
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Ostwald Ripening ◽  
Thermal Stability Of

scholarly journals Influence of Thermal Stability of Quartz and the Particle Size distribution of Burden Materials on the Process of Electrothermal Smelting of Metallurgical Silicon

2018 ◽  
Vol 34 (2) ◽  
pp. 1120-1125 ◽  
Author(s):  
Nikolay Nikolayevich Zobnin ◽  
Anatoliy Korneyevich Torgovets ◽  
Irina Anatolyevna Pikalova ◽  
Yuliya Sergeyevna Yussupova ◽  
Sergey Asifogly Atakishiyev
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Metallurgical Silicon ◽  
Thermal Stability Of

scholarly journals Theoretical analysis of particle size re-distribution due to Ostwald ripening in the fuel cell catalyst layer

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 779-789 ◽  
Author(s):  
Ambrož Kregar ◽  
Tomaž Katrašnik
Keyword(s):  
Particle Size ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Electric Potential ◽  
Ostwald Ripening ◽  
Particle Growth ◽  
Mean Particle Size ◽  
Fuel Cell Catalyst

Abstract The limited durability of hydrogen fuel cells is one of the main obstacles in their wider adoption as a clean alternative technology for small scale electricity production. The Ostwald ripening of catalyst material is recognized as one of the main unavoidable degradation processes deteriorating the fuel cell performance and shortening its lifetime. The paper systematically studies how the modeling approach towards the electrochemically driven Ostwald ripening in the fuel cell catalyst differs from the classical diffusion driven models and highlights how these differences affect the resulting evolution of particle size distribution. At moderately low electric potential, root-law growth of mean particle size is observed with linear relation between mean particle size and standard deviation of particle size distribution, similar to Lifshitz-Slyozov-Wagner theory, but with broader and less skewed distribution. In case of high electric potential, rapid particle growth regime is observed and qualitatively described by redeposition of platinum from a highly oversaturated solution, revealing the deficiencies of the existing platinum degradation models at describing the Ostwald ripening in the fuel cells at high electric potentials. Several improvements to the established models of platinum degradation in fuel cell catalysts are proposed, aimed at better description of the diffusion processes involved in particle growth due to Ostwald ripening.

scholarly journals From nucleation and coarsening to coalescence in metastable liquids

2020 ◽  
Vol 378 (2171) ◽  
pp. 20190247 ◽  
Author(s):  
Dmitri V. Alexandrov ◽  
Irina V. Alexandrova
Keyword(s):  
Mass Transfer ◽  
Particle Size ◽  
Distribution Function ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Ostwald Ripening ◽  
Intermediate Stage ◽  
Size Distribution Function ◽  
The Right ◽  
Transfer Mechanisms

The transition of a metastable liquid (supersaturated solution or supercooled melt) occurring from the intermediate stage (where the crystals nucleate and grow) to the concluding stage (where the larger particles evolve at the expense of the dissolution of smaller particles) is theoretically described, with allowance for various mass transfer mechanisms (reaction on the interface surface, volume diffusion, grain-boundary diffusion, diffusion along the dislocations) arising at the stage of Ostwald ripening (coalescence). The initial distribution function (its ‘tail’) for the concluding stage (forming as a result of the evolution of a particulate assemblage during the intermediate stage) is taken into account to determine the particle-size distribution function at the stage of Ostwald ripening. This modified distribution function essentially differs from the universal Lifshitz–Slyozov (LS) solutions for several mass transfer mechanisms. Namely, its maximum lies below and is shifted to the left in comparison with the LS asymptotic distribution function. In addition, the right branch of the particle-size distribution lies above and is shifted to the right of the LS blocking point. It is shown that the initial ‘tail’ of the particle-size distribution function completely determines its behaviour at the concluding stage of Ostwald ripening. The present theory agrees well with experimental data. This article is part of the theme issue ‘Patterns in soft and biological matters’.

Some Properties of Polyconjugated Polymers Obtained by Oxidative Polymerization of Benzylidene-m-Phenylenediamines

2021 ◽  
Vol 899 ◽  
pp. 563-569
Author(s):  
Timur A. Borukaev ◽  
A.Kh. Salamov ◽  
Andrei V. Orlov
Keyword(s):  
Thermal Stability ◽  
Electrical Conductivity ◽  
Particle Size ◽  
Electrical Properties ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Chemical Structure ◽  
Oxidative Polymerization ◽  
Thermal And Electrical Properties

New polyconjugated polymers have been synthesized by oxidative polymerization of benzylidene-m-phenylenediamines. The morphology, particle size distribution, thermal and electrical properties of the obtained polybenzylidene-m-phenylenediamines have been investigated. The morphology of the particles of the obtained polymers was determined. It was shown that the synthesized polybenzylidene-m-phenylenediamines exhibit noticeable thermal stability and electrical conductivity. In this case, the thermal stability and the process of decomposition of polybenzylidene-m-phenylenediamines substantially depend on the chemical structure of the side fragments of macromolecules.

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