Simultaneous Enhancement of the Activity and Durability of the Oxygen Reduction Reaction via Pd3Mo@Pt/C Catalysts

Abstract

To overcome the limitations of conventional bimetallic catalysts in facilitating the oxygen reduction reaction (ORR), we employed density functional theory (DFT) screening to evaluate ternary Pd₃X@Pt core@shell catalysts (X = transition metals), with the objective of increasing both the ORR activity and durability. Among the 25 candidates, Pd₃Mo@Pt emerges as the most promising catalyst, showing a combination of a low limiting potential and a high dissolution potential. Experimental validation reveals that the carbon-supported Pd₃Mo@Pt/C catalysts clearly exhibit exceptional mass activity (3.76 A mg_Pt^–1) and specific activity (1.67 mA cm^–2); these activities significantly surpass those of their Pt/C counterparts by factors of 10.2 and 3.18, respectively. Furthermore, these core@shell catalysts exhibit robust durability, while also exhibiting enhanced CO tolerance, as evidenced by CO stripping voltammetry. DFT calculations show that the superior activity and stability of Pd₃Mo@Pt/C are attributed to the optimal modulation of the Pt surface electronic structures by the core elements, particularly Mo.