Dimensional-Dependent Effects in Platinum Core-Shell-Based Catalysts for Fuel Cell Applications

The oxygen reduction reaction (ORR) activity of platinum catalysts can be affected by tuning the dimension. Experimental reports suggest that one-dimensional platinum catalysts have been identified as efficient ORR catalysts. With this objective, we have modeled one-dimensional Pt-90 nanorods (NRs) and investigated the origin of ORR activity. Core-shell effects within one dimension are investigated by modeling 3d metal core-based platinum NRs. Thermodynamic and electrochemical stability-based screening of core-shell NRs suggested Cu-42@Pt-48 as the most stable core-shell system. Systematic analysis of ORR energetics revealed higher ORR activity of Pt-90 NRs compared to the conventional Pt(1 1 1) surface catalyst, which is further improved by incorporating core-shell effects into the Cu-42@Pt-48 NR owing to the different reaction mechanisms associated with the core-shell structure. The activity modulation is principally governed by strain and charge-transfer effects. The dimensional effects are investigated by comparing the activities with two-dimensional surface and zero-dimensional nanocluster catalysts. The results obtained in this study provide fundamental insights into the dimensional effect of catalysts toward ORR activity.