US Patent 7381465 - Etchable core nanoparticle surrounded by non-etchable shell

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In order to promote chemical reactions often porous materials such as zeolites are used in applications such as water purification and crude oil processing. To improve the reactivity of some reactions it has been proposed to arrange nanopores close to catalytic nanoparticles. This patent from Japan Science and Technology Agency teaches a new type of material with an photoetchable nanoparticle (such as CdS) surround by SiO films resistant to photoetching and to create a void within the CdS. Claim 1 reads:


1. A core-shell structure having a void space of predetermined size inside a shell, comprising:

a core comprising nanoparticles, said core is a photoetchable solid;

a shell coating said core, said shell is a non-photoetchable material; and

a void space defined by a space between said core and said shell, wherein said predetermined size of said void space is 1 nm to about 50 nm in diameter.