Synthesis of platinum nanoclusters and electrochemical investigation of their stability

Platinum nanoclusters were synthesized using two methods: (a) ascorbic acid reduction of K2PtCl4, (b) an H2PtCl6 polyol process. Both processes yield clusters of platinum consisting of nanoparticles with a narrow size distribution. Experiments were conducted using platinum nanoclusters as the working electrode and bulk platinum wire as the counter electrode, both supported on inert, electronically conducting substrates. The electrodes were immersed in a PtCl4 + dimethyl sulfoxide electrolyte solution. The spacing between the electrodes was maintained at 1 mm or 6 mm. Electrical potential was measured across the two electrodes as a function of time. The samples (scraped off the nano-electrode) were examined using transmission electron microscopy (TEM). Experimental data show significantly lower kinetics of particle growth for the nanoclustered, uniformly sized particles as compared to commercially available carbon-supported platinum catalysts.