Correlation between platinum nanoparticle surface rearrangement induced by heat treatment and activity for an oxygen reduction reaction.

Heat treatment of nanoparticles could induce the surface rearrangement for more stable facet exposure induced by thermodynamics. By changing the heat treatment environment, we confirmed the correlation between the oxygen reduction activity and the effect of surface oxide and the degree of surface rearrangement of Pt nanoparticles. Native surface oxide was not a critical factor for oxygen reduction activity. However, the degree of surface rearrangement could affect the activity, which was confirmed by the surface sensitive techniques such as CO(ad) oxidation and potential of zero total charge. Analysis indicated that the driving force for nanoparticle surface rearrangement was affected by the heat treatment environment such as gas, in our case.