Iron corrosion in the “inert” supercritical CO₂, ab initio dynamics insights: How impurities matter

Journal Article · 20 January 2022 · Matter (Online)

DOI: https://doi.org/10.1016/j.matt.2021.12.019 · OSTI ID:1981703

Li, Qin-Kun ^[1]; Kutana, Alex ^[1]; Penev, Evgeni S. ^[1]; Yakobson, Boris I. ^[1]

---

1. Rice Univ., Houston, TX (United States)

Metal corrosion from exposure to supercritical fluids is a long-standing challenge lacking atomistic understanding for effective corrosion prevention in diverse important applications. Here, in this work, reactions relevant to corrosion in supercritical CO₂ (sCO₂), with H₂O and NO₂ as impurities, are revealed using ab initio molecular dynamics and enhanced sampling methods. While little reactivity is observed in bulk sCO₂, the iron surface is found to play a crucial almost-catalytic role in its own corrosion, activating the inert CO2 and hence facilitating $$\ast$$HCO₃– and $$\ast$$CO₃^2– formation at the interface. Moreover, the hydrogen bond network of $$\ast$$H₂O assists the H shuttling to the activated CO₂ and impurities, forming reactive species observed in experiments. Such atomistic insight elucidates the reaction mechanisms of metal corrosion in aqueous and supercritical fluids and can point to possible remedies.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-05CH11231; AC05-00OR22725
• OSTI ID: 1981703
• Journal Information: Matter (Online), Journal Name: Matter (Online) Journal Issue: 2 Vol. 5; ISSN 2590-2385
• Publisher: Cell Press/ElsevierCopyright Statement
• Country of Publication: United States
• Language: English