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- Title
In Situ Liquid Cell TEM Studies on Etching and Growth Mechanisms of Gold Nanoparticles at a Solid–Liquid–Gas Interface.
- Authors
Hutzler, Andreas; Fritsch, Birk; Jank, Michael P. M.; Branscheid, Robert; Martens, R. Christian; Spiecker, Erdmann; März, Martin
- Abstract
Etching and growth of gold nanoparticles at a solid–liquid–gas interface are investigated via in situ liquid cell transmission electron microscopy. For this purpose, the gold precursor tetrachloroauric acid is enclosed in the wells of a free‐standing, locally thinned silicon nitride film covered by few‐layer graphene. Etching of gold is attributed to hydroxide radicals generated by radiolysis and gaseous species which are located within a gas bubble. The etching mechanism comprises two distinct cases. In one case, the gas bubble is in direct contact with the gold particle, separated only by a thin liquid membrane. In the other case, the gold particle is thoroughly immersed in liquid in the vicinity of the particle. In the latter, etching molecules diffuse from the bubble through the liquid toward the surface of the nanoparticle and subsequently etch the gold platelet. During the particle etching process, concurrent nucleation and ripening of gold nanoparticles are observed. This growth is induced by local supersaturation of the solution with gold ions. Experimental results show that the growth process is limited by diffusion, even though the diffusivity of reactants is very low due to narrow‐channel effects compared against the diffusivity of solvated ions in bulk liquids.
- Subjects
GOLD nanoparticles; TRANSVERSE electromagnetic cells; SILICON nitride films; THERMAL diffusivity; TRANSMISSION electron microscopy; LIQUID surfaces; GOLD ores; COMPOSITE membranes (Chemistry)
- Publication
Advanced Materials Interfaces, 2019, Vol 6, Issue 20, pN.PAG
- ISSN
2196-7350
- Publication type
Article
- DOI
10.1002/admi.201901027