Computational Screening for ORR Activity of 3d Transition Metal Based M@Pt Core-Shell Clusters

Core-shell nanoparticles are widely recognized as potential catalysts for oxygen reduction reaction (ORR) occurring at the cathode of proton exchange membrane (PEM) fuel cells. A comprehensive analysis of ORR activity of low-cost core-shell nanoparticles is still lacking from previous screening studies. To address this, a complete series of 3d metal based platinum core-shell nanoclusters are designed and scrutinized for ORR activity as well as stability. The adsorption behavior of ORR intermediates is observed to highly depend on the core-shell combination. The analysis of ORR energetics along the associative pathway shows a nonuniform trend in free energy changes and rate-determining steps. As compared to earlier reports, we show that a single intermediate binding energy is not enough for interpreting the ORR activity trends. Ti, Ni, and Cu based core shell clusters are observed to have elevated activity as compared to bare platinum nanocluster and periodic platinum (111) surface. The origin of activity differences is explained via structural, charge transfer, and electronic structure analyses.