Agglomerates of nanoparticles

Abstract

Nanoparticles tend to agglomerate. The process of agglomeration is ruled by thermodynamics. Depending on the sign of the enthalpy of interaction, ensembles consist of (repelling) poorly agglomerated or (attracting) highly agglomerated particles. For these two cases different distribution functions for the agglomerates were found. The size distribution of the agglomerates is ruled by the maximum of the entropy of the ensemble of agglomerates, which is calculated using Gibbs formula of entropy. The exact determination of the size distribution of the agglomerates also gives the maximum size of the agglomerates. These considerations lead to an improved understanding of ensembles of agglomerated nanoparticles.

Cryogenic electron tomography to determine thermodynamic quantities for nanoparticle dispersions

“…The exponential decay of the aggregate populations versus aggregate states is known for nanoparticle dispersions. [52][53][54] This phenomenon is indeed validated by both AUC-SV (weight-based distribution) and by our method (number-based distribution) for a whole range of concentrations from both at low range (AUC-SV) and to high range (present method). The agreement found confirms that vitrification did not alter the aggregation states.…”

Bulky olefin epoxidation under mild conditions over Mo-based oxide catalysts

“…1) and chemical compositions (Table S1 †), albeit considerably different S BET (54 and 402 m 2 g −1 , M = Ta and Nb, respectively). Possible differences in the size/density/structure of the nanoparticle ensembles or agglomerates, 44,45 may at least partly influence the interparticle void space and total specific surface area. For example, for the Mo(50D)M-0.3 family, S BET (Table S2 †) increased with decreasing particle size: M = Ta (19 nm width; 98 m 2 g −1 ); M = W (7-12 nm; 118 m 2 g −1 ); M = Nb (3-5 nm; 254 m 2 g −1 ).…”

The Use of Synthesized CoO/Co3O4 Nanoparticles as A Corrosion Inhibitor of Low-Carbon Steel in 1 M HCl

“…In addition to chemical bonding, as CoO/Co 3 O 4 NPs contains many O atoms that have single-pair electrons and π-conjugate electrons, the coordinated interaction can be formed via charge sharing and transfer, thus introducing a chemisorption adsorption process. Therefore, CoO/Co 3 O 4 NPs adsorption on the surface of low-carbon steel surface is a spontaneous physicochemical adsorption process [29,30]. The negative value of ∆H • ads indicates that the adsorption is exothermic, and the positive value of ∆S • ads indicates an increase in randomness due to the competition of nanoparticles ions at the active sites on the low-carbon steel surface [31].…”