Selective attachment of gold nanoparticles to nitrogen-doped carbon nanotubes

Gold nanoparticles were selectively attached to chemically functionalized surface sites on nitrogen-doped carbon (CN(x)) nanotubes. A cationic polyelectrolyte was adsorbed on the surface of the nanotubes by electrostatic interaction between carboxyl groups on the chemically oxidized nanotube surface and polyelectrolyte chains. Negatively charged 10 nm gold nanoparticles from a gold colloid suspension were subsequently anchored to the surface of the nanotubes through the electrostatic interaction between the polyelectrolyte and the nanoparticles. This approach provides an efficient method to attach other nanostructures to carbon nanotubes and can be used as an illustrative detection of the functional groups on carbon nanotube surfaces.