Reduced O diffusion through Be doped Pt electrodes

TL;DR

This study uses first principles calculations to identify Be doping as an effective method to slow oxygen diffusion in polycrystalline Pt electrodes by segregating at grain boundaries and trapping oxygen.

Contribution

It demonstrates that Be doping at grain boundaries significantly retards oxygen diffusion in Pt, supported by both theoretical calculations and experimental validation.

Findings

Be segregates to Pt grain boundaries at interstitial and substitutional sites.

Be reduces oxygen mobility by repelling and trapping oxygen at grain boundaries.

Experimental results confirm Be's role in decreasing oxygen diffusion in Pt.

Abstract

Using first principles electronic structure calculations we screen nine elements for their potential to retard oxygen diffusion through poly-crystalline Pt (p-Pt) films. We determine that O diffuses preferentially as interstitial along Pt grain boundaries (GBs). The calculated barriers are compatible with experimental estimates. We find that Be controls O diffusion through p-Pt. Beryllium segregates to Pt GBs at interstitial (i) and substitutional (s) sites. i-Be is slightly less mobile than O and it repels O, thus stuffing the GB. s-Be has a high diffusion barrier and it forms strong bonds to O, trapping O in the GB. Experiments confirm our theoretical predictions.