Enhanced water resistance mechanism in Ag-Hollandite for catalytic ozone decomposition

Abstract

Catalytic ozone (O3) decomposition at ambient temperature is an efficient method to mitigate O3 pollution. However, practical application is hindered by the poor water resistance of catalysts. Herein, Ag-Hollandite (Ag-HMO) with varying Ag+ content was synthesized. Catalysts with more Ag+ exhibited improved efficiency and water-resistance, with the optimal one maintaining 98% O3 conversion at 70% relative humidity (RH) within 8 h. Physicochemical characterizations revealed that Ag+ had entered the tunnel of OMS-2, facilitating oxygen species removal. Notably, enhanced H2O desorption and the complete inhibition of chemisorbed water formation on Ag-HMO were the primary reasons for its high-efficiency O3 conversion across a wide humidity range. The underlying mechanism arises from the charge redistribution induced by the Ag-O interaction within the tunnel, which reduces acidity and modulates hydrophilicity. This study aims to contribute insights for designing catalysts with higher water-resistance.