title: Spontaneous formation of hollow cobalt oxide nanoparticles by the Kirkendall effect at room temperature at the water-air interface.
abstract: We observe the spontaneous formation of hollow cobalt oxide nanoparticles at room temperature, indicating an enhancement of the solid-state diffusion at the nanoscale. Single crystal cobalt nanoparticles covered by a hydrophobic organic layer were transformed spontaneously into CoO hollow nanoparticles when deposited on the water-air interface in a matter of a few hours. The presence of water modifies the reactivity on the nanoparticle surface favoring the formation of the hollow structure; otherwise Co-CoO core-shell nanoparticles are obtained. The CoO hollow nanoparticles are formed only in an intermediate state, and after a period of time these structures finally undergo disintegration to form minor CoO entities.
authors: Catalan Institute of Nanotechnology-ICN, Campus de la UAB, Edifici Q-ETSE, 08193 Bellaterra, Barcelona, Spain.
authors: Miriam
authors: M
authors: Varón
authors: Isaac
authors: I
authors: Ojea-Jimenez
authors: Jordi
authors: J
authors: Arbiol
authors: Lluis
authors: L
authors: Balcells
authors: Benjamín
authors: B
authors: Martínez
authors: Víctor F
authors: VF
authors: Puntes