Deciphering CO oxidation on SnO₂ nanosheets: A multinuclear solid-state NMR spectroscopic approach

SnO2 nanosheets exhibit exceptional low-temperature CO oxidation activity, yet the nature of their active sites remains enigmatic. Employing solid-state 119Sn and 17O NMR spectroscopy, we deconstructed the intricate structure of active Sn and oxygen species involved in this process. We identified diverse Sn and O environments, revealing surface SnIV sites capable of activating O2 into a critical bidentate η2–O2 species responsible for CO conversion into CO2. In-situ FT-IR spectroscopy studies further revealed the involvement of a carbonate-mediated Mars-van Krevelen mechanism.