A novel γ-like MnO catalyst for ozone decomposition in high humidity conditions.

MnO catalysts have been widely studied for catalytic gaseous ozone decomposition. However, their poor moisture resistance often leads to undesirable catalytic effects in the presence of high humidity. In this study, a novel catalyst with γ-like MnO was synthesized using the selective dissolution method on LaMnO perovskites. The as-prepared catalyst exhibited quite stable ozone conversion of ~90% within 12 h under 75% relative humidity (400-800 ppm of ozone, 30 °C, 150 000 mL·g·h of WHSV). In contrast, traditional γ-MnO catalyst showed deficient resistance to HO and sensitivity to space velocity. Detailed characterizations showed that the larger number of oxygen vacancies induced by structure reconstruction of the γ-like MnO and residual La cations facilitated ozone decomposition in humid atmosphere. Finally, the reaction rate of ozone decomposition was proposed by a kinetic study, which further proved that the amount and hydrophilicity of oxygen vacancies are the determinants of the first-order reaction rate constant.