Atomic force microscopy of platinum nanoparticles prepared on highly oriented pyrolytic graphite

Platinum nanoparticles with a narrow size distribution were prepared on highly orientated pyrolytic graphite (HOPG) surfaces by electrochemical deposition. The surfaces were characterized by atomic force microscopy operated in air in the tapping mode. Particle sizes between 20 and 100 nm can be prepared by using different deposition times and overpotentials. The deposition appears to be controlled by interfacial electron transfer and diffusion. Adding a supporting electrolyte will reduce non-faradiac charging resistance and the apparent deposition time scale. While isolated particles are formed at short deposition times, connected clusters of various morphologies can be observed at long deposition times.