Interconnected surface-vacancy-rich PtFe nanowires for efficient oxygen reduction

Abstract

Catalysts that boost the oxygen reduction reaction (ORR) are highly needed for fuel cells and metal–air batteries. Herein, we report the preparation of surface-vacancy-rich PtFe interconnected nanowires as an excellent ORR catalyst. When utilized in both alkaline and acidic electrolytes, this hierarchically structured catalyst shows high mass activities at 0.9 V versus the reversible hydrogen electrode (RHE) (alkaline electrolyte: 3.65 A mg_Pt⁻¹ and acid: 1.10 A mg_Pt⁻¹), high half-wave potential (alkaline electrolyte: 0.959 V vs. RHE and acid electrolyte: 0.924 V vs. RHE), and high stability (almost no activity loss after 10 000-cycle accelerated durability testing). Density functional theory calculations reveal that the presence of vacancies on the Pt-skin provides rich active ORR sites that can weaken the bonding strength and adsorption of O-containing intermediates. This paper presents a facile strategy to assemble efficient hierarchically structured electrocatalysts with rich surface defects for devices such as fuel cells.