Electron-enriched metastable Fe2+ sites with enhanced sulfur resistance for catalytic methanethiol (CH3SH) decomposition.

The catalytic decomposition of methanethiol (CH3SH) over metal oxide catalysts faces an inherent challenge that high-valent metal oxides (e.g., Fe3+) typically enhance reactivity, while they also exhibit severe sulfur susceptibility, leading to rapid deactivation. Here, a silanol nests-mediated nanoconfinement strategy is developed to simultaneously tune the electronic state and surface acidity of iron (Fe) based catalysts, affording Fe/deAlMCM. Fe/deAlMCM maintains stable operation for more than 3000 min while exhibiting CH3SH conversion comparable to that of a conventional high-valent Fe3+ catalyst (Fe/MCM), which deactivates within 750 min. X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XFAS), pyridine-adsorbed infrared spectroscopy (Py-IR) and density functional theory (DFT) calculation reveal that silanol-nest anchoring enrich the electron density of metastable Fe2+ sites, promoting CH3SH activation via enhanced charge transfer while weakening FeS interactions and mitigating irreversible sulfur poisoning. Meanwhile, Al removal and Fe incorporation enhance Lewis acidity and suppress Brønsted acidity, redirecting CH3SH adsorption toward the sulfur terminals and thereby limiting carbon deposition. This work identifies a silanol nest-enabled electronic-acid synergy and provides a design strategy for developing sulfur-resistant catalysts for sulfur-containing volatile organic compounds.