First-Principles Investigation into the Contributions of ORR and HER in Magnesium Corrosion

Recent experiments have demonstrated that oxygen reduction reaction (ORR) can contribute significantly to Mg corrosion in addition to hydrogen reduction reaction (HER). However, its contributions at various stages of Mg corrosion remains unclear. Using DFT calculations, we investigate ORR and HER on both pristine and Fe/Mn alloyed Mg, MgO and Mg(OH) 2 during Mg corrosion. We found that both HER and ORR on pristine and alloyed Mg contribute to the overall cathodic current density: HER contributes much more significantly than ORR, while the ORR contribution is up to the mass transport limit and would diminish over time. In addition, we found that ORR activities on Fe/Mn alloyed MgO are high, suggesting an alternate source of cathodic ORR contribution during the whole course of Mg corrosion. Excellent agreements are found between our findings and a recent experiment.

Automated summary

Recent experiments have shown that oxygen reduction reaction (ORR) plays a significant role in magnesium (Mg) corrosion along with hydrogen reduction reaction (HER). However, the contributions of ORR at different stages of Mg corrosion are still unclear. Using DFT calculations, we investigated the performance of ORR and HER on pristine and Fe/Mn alloyed Mg, MgO, and Mg(OH)2 during Mg corrosion. Our findings reveal that both HER and ORR on pristine and alloyed Mg contribute to the overall cathodic current density, with HER playing a more prominent role than ORR. However, the contribution of ORR diminishes over time due to mass transport limitations. Moreover, we found that ORR activities on Fe/Mn alloyed MgO are high, indicating an alternative source of cathodic ORR contribution throughout the entire course of Mg corrosion. Our results are in excellent agreement with recent experimental data.