High vacancy formation energy boosts the stability of structurally ordered PtMg in hydrogen fuel cells.

ABSTRACT: Alloys of platinum with alkaline earth metals promise to be active and highly stable for fuel cell applications, yet their synthesis in nanoparticles remains a challenge due to their high negative reduction potentials. Herein, we report a strategy that overcomes this challenge by preparing platinum-magnesium (PtMg) alloy nanoparticles in the solution phase. The PtMg nanoparticles exhibit a distinctive structure with a structurally ordered intermetallic core and a Pt-rich shell. The PtMg/C as a cathode catalyst in a hydrogen-oxygen fuel cell exhibits a mass activity of 0.50 A mg_Pt^-1 at 0.9 V with a marginal decrease to 0.48 A mg_Pt^-1 after 30,000 cycles, exceeding the US Department of Energy 2025 beginning-of-life and end-of-life mass activity targets, respectively. Theoretical studies show that the activity stems from a combination of ligand and strain effects between the intermetallic core and the Pt-rich shell, while the stability originates from the high vacancy formation energy of Mg in the alloy.

SUBMITTER: Gyan-Barimah C 

PROVIDER: S-EPMC11327255 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature