Construction of hydrophobic microenvironment on Sn⁰@SBA-15 for efficient and stable iodine gas capture

Tin-based materials are promising for iodine capture. However, they suffer from the instability of adsorption product SnI₄ that is easily hydrolyzed even in atmospheric environment due to the presence of moisture. Herein, we report a strategy of constructing the hydrophobic microenvironment on Sn⁰@SBA-15 materials, which isolates moisture and subsequently stabilizes SnI₄. Hydrophobic Sn⁰@SBA-15 materials (P-Sn⁰@SBA-15) were fabricated by polymethylhydrosiloxane (PHMS) modification and applied for iodine capture. The obtained P-Sn⁰@SBA-15 exhibited a record high iodine adsorption capacity (2599 mg/g) among inorganic adsorbents. The dominant adsorption mechanism was found that Sn⁰ reacted with I₂ to form SnI₄. Remarkably, SnI₄ in P-Sn⁰@SBA-15 was stable up to 3 months exposure to humid atmosphere, while almost all SnI₄ in Sn⁰@SBA-15 was hydrolyzed. The obtained P-Sn⁰@SBA-15 could be added to the list of iodine adsorbents due to its excellent adsorption capacity and stability. Moreover, the facile strategy could provide reference for the development of other functional materials.