Preparation of platinum nanoparticles on n-GaN(0001) substrate by means of electrodeposition

Nanoparticles of platinum (Pt) were directly prepared on n-GaN(0001) by a potentiostatic electrodeposition in 0.5 M H2SO4 + 8 mM H2PtCl6 solution and fully characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray analysis (EDAX). The as-deposited nanoparticles, whose morphology and size were dependent on the applied potential and time, were made of platinum. The real surface area and catalytic properties of Pt nanoparticles prepared at different potentials were estimated by cyclic voltammetry in 0.5 M H2SO4 and by chronoamperometry in 0.5 M H2SO4 + 0.2 M CH3OH solutions, respectively. The maximum of real surface area and the best catalytic activity of Pt nanoparticles were obtained at the potential of −0.7 V.