Fig. 29. (left) Schematic representation of the electron transfer reactions in the substrate and sample by means of SECM and (right) SECM image of the electron transfer reaction of H⁺/H at five Pt nanoparticles in 2 mM HClO₄ and 10 mM NaClO₄ with the tip polarized at −1.0 V and the substrate at −0.4 V vs. a Pt quasi reference electrode (QRE). Pt nanotip was scanned at 200 nm s⁻¹. Reproduced with permission from ref. 43 © 2016 American Chemical Society.