Tweaking palladium electronic structure to attain oxygen reduction activity superior to platinum/C

Abstract

Enhancing oxygen reduction (ORR) activity through alloying is crucial to improve the performance of a fuel-cell catalysts. In this work, we have studied the alloying effects of 4f rare-earth (RE) metals with palladium. The modified catalyst exhibits better activity (E_onset = 1 V and E_1/2 = 0.88 V) and higher selectivity toward H₂O (∼97%) compared to the state-of-the-art catalysts due to complete dissociation of O₂. Hirshfeld charge analysis and 2D-electron localization function reveal improved adsorbate-adsorbent interaction on the catalyst surface. This work paves a strategy to design highly selective non-Pt-based catalysts for the ORR by controlling electronic structures and surface oxide formation.