Linear dependence of potential drop at the passive film/solution interface on film-formation potential and pH: Combining first-principles calculations with experimentsShow others and affiliations
2024 (English)In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 240, article id 112437Article in journal (Refereed) Published
Abstract [en]
Potential drop at the oxide film/solution interface plays a critical part in numerous electrochemical processes, especially for the passivated metal-electrolyte system, affecting the passive film breakdown and the pitting initiation. There are still some controversies over the dependence of potential drop at the passive film/solution interface (φf/s) on potential and pH of electrolyte. Herein, we develop a model presenting the linear dependence of φf/s on both potential and pH, as represented by φf/s=φf/s(V=0,pH=0)0+αV+βpH. By analyzing the surface charge (i.e., point of zero charge, pHpzc) and performing first-principles calculations, we provide the insights into the effect of potential and pH on the φf/s, and into the linear relation between φf/s with pH beyond the Nernst relation that is attributed to the role of point defects in pHpzc of passive film on iron. In addition, two methods, e.g., a combination of Mott-Schottky measurement with first-principles, contact angle titration, are suggested to determine the values of α, β and φf/s(V=0,pH=0)0, respectively. The study of passivity of iron in borate buffer solutions validates our model.
Place, publisher, year, edition, pages
Elsevier BV , 2024. Vol. 240, article id 112437
Keywords [en]
First-principles calculations, Flatband potential, Interfacial potential drop, Passive film, Surface charge
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-353911DOI: 10.1016/j.corsci.2024.112437ISI: 001319393300001Scopus ID: 2-s2.0-85204052043OAI: oai:DiVA.org:kth-353911DiVA, id: diva2:1900986
Note
QC 20241008
2024-09-252024-09-252024-10-08Bibliographically approved