Exploring the impact of S-doped Fe-N-C materials on the ORR mechanism within a constant potential solvation model.

• Based on the constant potential implicit solvent model, a realistic electrocatalytic environment was simulated. • The ORR activity of S-coordinated FeN 4 was simulated using a constant potential implicit solvent model. • It was found that FeN 4 S2 exhibited the highest activity under -2e conditions with an overpotential of 0.39V. • The high electronegativity of S enhances the valence state of Fe, weakens adsorption of *OH, and promotes the ORR process. The widespread application of S doping in Fe-N-C materials aims to enhance the catalytic activity for oxygen reduction reactions (ORR). However, the current doping strategies are primarily centered on the first coordination layer encompassing Fe atoms. Consequently, this study employs first-principles calculations to compute the formation and binding energies of FeN 4 doped with S atom. It further delves into the influence of diverse doping sites on catalyst stability and meticulously analyzes the configurations and corresponding ORR activities of four catalysts, namely FeN 4 S-N (Number=0∼3), utilizing a constant-potential implicit solvent model to simulate authentic electrocatalytic environments. The findings reveal that under vacuum conditions, FeN 4 S1 exhibits the utmost ORR activity, boasting a potential of 0.53 V. Conversely, within the constant-potential implicit solvation model, FeN 4 S2 emerges as the catalyst with the highest ORR activity, achieving a potential of 0.39 V. Therefore, calculations leveraging the constant-potential solvation model offer more realistic insights into catalyst design, thereby guiding the development of superior catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]