Dimensional-Dependent Effects in Platinum Core–Shell-Based Catalysts for Fuel Cell Applications
Nishchal Bharadwaj, Akhil S. Nair, Biswarup Pathak
Abstract
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 Pt90 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 Cu42@Pt48 as the most stable core–shell system. Systematic analysis of ORR energetics revealed higher ORR activity of Pt90 NRs compared to the conventional Pt(111) surface catalyst, which is further improved by incorporating core–shell effects into the Cu42@Pt48 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.