<p>Using a non-aqueous desulfurization solution based on coordination interactions to capture hydrogen sulfide is a promising method, and it does not lead to the precipitation of sulfur. However, due to the low efficiency of oxidation regeneration under strong acidic conditions, its practical application has been hindered. To address this bottleneck, we developed a carbon-encapsulated iron catalyst designed to facilitate heterogeneous O₂-driven regeneration while maintaining exceptional acid resistance. This catalyst was synthesized via a conformal resorcinol–formaldehyde coating on hydrothermally prepared Fe₂O₃ nanoparticles, followed by a controlled carbonization process. This approach yields a robust core–shell architecture, where a mixed-valence Fe₃O₄ core is shielded by a continuous carbon sheath. Systematic phase analysis reveals that a calcination temperature of 550&#xa0;°C is critical for stabilizing the Fe₃O₄ phase, whereas excessive temperatures trigger over-reduction to metallic iron. In subsequent regeneration trials, the carbon-coated Fe₃O₄ significantly accelerated the recovery of the oxidation–reduction potential (ORP) during O₂ aeration, effectively restoring the H₂S absorption capacity of the liquor. Crucially, the post-reaction characteristic analysis has highlighted the durability of this design: the morphology and surface integrity of the catalyst remained intact after five cycles, and the loss of iron elements was only 0.71%. These findings highlight carbon encapsulation as a useful strategy for integrating efficient interfacial redox catalysis with long-term structural stability in corrosive acidic environments.</p>