Al(13)@Pt(42) Core-Shell Cluster for Oxygen Reduction Reaction

To increase Pt utilization for oxygen reduction reaction (ORR) in fuel cells, reducing particle sizes of Pt is a valid way. However, poisoning or surface oxidation limits the smallest size of Pt particles at 2.6 nm with a low utility of 20%. Here, using density functional theory calculations, we develop a core-shell Al(13)@Pt(42) cluster as a catalyst for ORR. Benefit from alloying with Al in this cluster, the covalent Pt-Al bonding effectively activates the Pt atoms at the edge sites, enabling its high utility up to 70%. Valuably, the adsorption energy of O is located at the optimal range with 0.0–0.4 eV weaker than Pt(111), while OH-poisoning does not observed. Moreover, ORR comes from O(2) dissociation mechanism where the rate-limiting step is located at OH formation from O and H with a barrier of 0.59 eV, comparable with 0.50 eV of OH formation from O and H(2)O on Pt(111).