The degradation of transition metal@Pt core-shell nanoparticle catalyst in fuel cell application

Electrocatalysts at acidic media face the inactivation and degradation problems with the complex thermodynamic process. A density functional theory (DFT) calculation is performed to investigate the galvanic and pitting etching process of metal@Pt (M@Pt) core-shell nanoparticles (12 transition elements are selected to replace the core atoms, respectively). The dissolution process with atomic etching follows the dissolution potential site-dependence phenomena and the dissolution potential of Pt shell is negative linear correlation with the average d-band center of Pt shell. We have found that the specific shape effect, core-shell contact area and period effect both affect the potential difference at each step in the dissolution process. Meanwhile, the core atom segregation reduces the dissolution potential to form the defect on outermost shell is the driven force of halogen-pitting. By selecting 12 core elements and three specific shapes M@Pt nanoparticles, Ir@Pt nanoparticle with the TCO-structure has high initial and multistep dissolution process along the galvanic etching-process and good performance at pitting corrosion are the strong candidates for nanoparticle catalysts.