High vacancy formation energy boosts the stability of structurally ordered PtMg in hydrogen fuel cells.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39147744.
- Also identified by DOI 10.1038/s41467-024-51280-2 and PMC identifier 11327255.
- Licence recorded as CC BY-NC-ND.
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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<sub>Pt</sub><sup>-1</sup> at 0.9 V with a marginal decrease to 0.48 A mg<sub>Pt</sub><sup>-1</sup> 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.