CONTEXT: ⁺. METHODS: Density functional theory (DFT) calculations were performed under periodic boundary conditions using the PW91 exchange-correlation functional and plane-wave basis sets and Vanderbilt ultrasoft pseudopotentials. A Hubbard U correction of 2 eV was applied to surface Fe atoms. Calculations were carried out using the Quantum ESPRESSO 6.2.1 package. Activation barriers were computed using the nudged elastic band method, and atomic charges were obtained through Löwdin population analysis.
Bazan et al. (2026) studied this question.