Achieving HighlyMoisture-Tolerant Ozone Decompositionover Pd/MnO₂–HAC Monolith Catalyst

MnO₂ has been widely studied as a catalyst for ozone decomposition. However, poor moisture resistance hinders its further development, and there is still a lack of research on the implementation of a MnO₂ based monolithic catalyst. To address these issues, a series of Pd-loaded MnO₂ catalysts (Pd/MnO₂) were developed, and the moisture tolerance was remarkably enhanced. Under 90% relative humidity and 5 ppm of O₃, the monolithic catalyst (Pd/MnO₂–HAC), prepared by coating the powder catalyst onto honeycomb activated carbon (HAC), achieved 100% ozone conversion for 5 days. XPS, O₂–TPD, ESR, and comparison studies revealed that the incorporation of Pd resulted in more oxygen vacancies (V_O) on the surface of MnO₂, which largely facilitated ozone decomposition. Moreover, the competitive adsorption of water molecules was mitigated over Pd/MnO₂, while the desorption of O₂^2– intermediate was accelerated, as identified by H₂O-TPD and in situ diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy studies. These findings highlight the Pd/MnO₂–HAC catalyst as a robust and moisture-tolerant solution for ozone decomposition, demonstrating significant potential for practical environmental applications.