Mitigating oxygen reduction reaction barriers: An in-depth first-principles exploration of high-entropy alloy as catalysts

Abstract

This study investigates the effectiveness of high-entropy alloys (HEAs) as catalysts for reducing the energy barrier of the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). Four HEAs—IrPdPtRh, CoCrFeNi, NbMoTaW, and TiZrNbTa—are analyzed as potential catalysts. This superiority arises from the shift in the overall d-band center position towards negative energy in HEAs. The study suggests that an increased standard deviation of atomic valences within HEAs correlates positively with improved ORR efficiency, indicating it as a potential design indicator for cost-effective catalysts. Moreover, predictions of valence variations based on differences in electronegativity between individual elements are proposed. Additionally, the research highlights that additional surface adsorption of Pt on HEAs would further enhance ORR activity.