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Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water. [1] The colloid is coloured usually either wine red (for spherical particles less than 100 nm) or blue-purple (for larger spherical particles or nanorods). [2]
Gold clusters, a part of cluster chemistry, is a term used to describe molecular clusters of gold or larger colloidal particles. Both types can described as nanoparticles, with diameters of less than one micrometer. [1] Gold nanoclusters have, despite intense efforts, as yet no commercial applications.
A nanoshell, or rather a nanoshell plasmon, is a type of spherical nanoparticle consisting of a dielectric core which is covered by a thin metallic shell (usually gold). [1] These nanoshells involve a quasiparticle called a plasmon which is a collective excitation or quantum plasma oscillation where the electrons simultaneously oscillate with ...
Gold nanoparticles can be purchased or synthesized via a variety of methods. [12] Several strategies exist for functionalizing gold nanoparticles with single-stranded DNA; one of the most commonly utilized strategies involves introducing thiol-terminated DNA to a solution of gold nanoparticles and gradually increasing the concentration of a salt, like NaCl.
Gold nanoparticles in the size range of 2 to 5 nm catalyze CO oxidation with a TOF of about 1 s −1 at temperatures below 273 K (0 °C). The catalytic activity of nanoparticles is brought about in the absence of moisture when the support is semiconductive or reducible, e.g. TiO 2, MnO 2, Fe 2 O 3, ZnO, ZrO 2, or CeO 2
Nanoparticles can take on a non-spherical shape, such as this star-shaped gold nanoparticle. Morphology refers to the physical shape of a particle, as well as its surface topography, for example, the presence of cracks, ridges, or pores. Morphology influences dispersion, functionality, and toxicity, and has similar considerations as size ...
An SEM image of epitaxial nanowire heterostructures grown from catalytic gold nanoparticles. There are two basic approaches to synthesizing nanowires: top-down and bottom-up. A top-down approach reduces a large piece of material to small pieces, by various means such as lithography, [5] [6] milling or thermal oxidation.
Nanosheets can also be prepared at room temperature. For instance, hexagonal PbO (lead oxide)) nanosheets were synthesized using gold nanoparticles as seeds under room temperature. [3] The size of the PbO nanosheet can be tuned by gold NPs and Pb 2+ concentration in the growth solution. No organic surfactants were employed in the synthesis process.