(a) TEM image of a single Au nanoparticle immobilized on a Pt nanoelectrode. (b) CVs at 10 mV/s of a 9.0 nm bare Pt electrodes before (black), after APTMS-modification (red), and after modifying with a 24 nm Au particle (green) in 5.0 mM K3Fe(CN)6 and 0.2 M KCl. (c) CVs at 10 mV/s of a bare 7 nm Pt nanoelectrode (black), a 14 (red), an 18 (green), and a 24 nm Au SNPEs (blue) in an oxygen-saturated 0.10 M KOH solution. Reproduced with permission from ref 15. Copyright 2010 American Chemical Society.