Flower-like Polymorphic\nMnO<sub><i>x</i></sub> Constructed by In Situ L–T\nTransition with Superior\nPerformance in the Catalytic Ozonation of Dimethyl Sulfide under Humid\nConditions

To improve the water resistance of manganese oxide (MnO<sub><i>x</i></sub>) in the catalytic ozonation of dimethyl\nsulfide\n(DMS) under humid conditions, polymorphic MnO<sub><i>x</i></sub> was synthesized based on δ-MnO<sub>2</sub> with reference\nto the in situ layer-to-tunnel (L–T) transition of minerals\nin a natural environment. The constructed polymorphic MnO<sub><i>x</i></sub>(Mn–SH) possessed abundant α–δ\n(α(Mn)-O-δ(Mn)) interfaces and exhibited superior catalytic\nactivity for the conversion of DMS, ensuring more than 91% of DMS\nremoval under harsh conditions [relative humidity (RH) = 80%] and\nexcellent stability after testing for 20 h (RH = 60–80%). In\nsitu DRIFTS spectra and theoretical calculations demonstrated that\nα–δ interfaces facilitated the formation of active\nhydroxyl groups (−OH) through H<sub>2</sub>O dissociation,\nwhich can participate in ozone (O<sub>3</sub>) activation and avoid\nthe deactivation caused by H<sub>2</sub>O. Simultaneously, more Brønsted\nacid sites formed through H<sub>2</sub>O dissociation, which promoted\nDMS adsorption and decomposition. This study gives an understanding\nof the role of α–δ interfaces in promoting activity\nfor catalytic ozonation and provides a convenient strategy to construct\npolymorphic MnO<sub><i>x</i></sub> with enhanced water resistance,\nwhich can be applied to existing MnO<sub><i>x</i></sub> used\nfor catalytic ozonation of sulfur-containing compounds from livestock\nfarms and the petroleum industries.