Surface Reconstruction and Reactivity of Platinum Iron Oxide Nanoparticles

The electrochemical stability of platinumiron oxide nanoparticles has been studied using X-ray absorption spectroscopy. Samples were monitored for changes in their surface structure and elemental composition after electrochemical cycling in acidic media, which were then correlated with their electronic properties and a thorough analysis of their electrocatalytic activities. In addition to the observation of significant surface restructuring, greater Fe content following electrochemical treatment was found to be associated with higher half-wave potentials and specific current densities (up to 0.965 +/- 0.001 V-RHE and 1.32 +/- 0.03 X 10(-5) mA cm(-2), respectively). This work highlights the potential to improve the electrocatalytic activity of platinumiron oxide nanoparticles by controlling the Fe content and platinumiron bonding, and demonstrates the critical importance of characterizing these nanocatalysts both before and after use.