Dense Decorate of sub-5nm Au NPs

"Formation of gold nanoparticles supported on carbon nanotubes by using an electroless plating method"

Ma, X.; Lun, N.; Wen, S. Diam. Relat. Mater. 2005, 14, 68-73.
doi:10.1016/j.diamond.2004.07.002

Points:
"Electroless plating with gold on CNTs cannot be succeeded without any activation of the surfaces."


"Pd/Sn catalyticnuclei in a Sn colloidal layer were first introduced onto the surfaces of the oxidized CNTs; after being washed with HCland distilled water, the Sn protective layer was preferentially dissolved and the Pd catalytic nuclei were exposed to agreater extent. In the following step of electroless plating,the individual Pd catalytic centers deposited on the surface of CNTs would reduce gold ions to neutral gold atoms and formed homogeneous dispersed and high-density nucleation centers of gold islands."

Materials: Au-MWNT

Synthesis:
Electroless Plating:

• KBH4 as the active reducing agent.
• MWNT (CVD from acetylene, H2SO4/HNO3, 140 C, 6h) was sonicated in activation solution (SnCl2/PdCl2/HCl, detailed preparation described), washed with 1M HCl/water repeatedly, and stirred in the plating bath for ~15 min at 25C.
• The plating is highly sensitive to the parameters (temp, conc, pH). The reagents should be added in due course.

Characterization:

• TEM
• EDX

Properties:
Size: 3-4 nm (TEM)
Stability: stable against repeated washing and sonication

Speculated Application:
Catalysis