Achieving Highly Moisture-Tolerant Ozone Decomposition over Pd/MnO<sub>2</sub>–HAC Monolith Catalyst
Zixin Liu, Xinming Liang, Jinhua Ye, Lequan Liu
Abstract
MnO 2 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 MnO 2 based monolithic catalyst. To address these issues, a series of Pd-loaded MnO 2 catalysts (Pd/MnO 2 ) were developed, and the moisture tolerance was remarkably enhanced. Under 90% relative humidity and 5 ppm of O 3, the monolithic catalyst (Pd/MnO 2 –HAC), prepared by coating the powder catalyst onto honeycomb activated carbon (HAC), achieved 100% ozone conversion for 5 days. XPS, O 2 –TPD, ESR, and comparison studies revealed that the incorporation of Pd resulted in more oxygen vacancies (V O ) on the surface of MnO 2, which largely facilitated ozone decomposition. Moreover, the competitive adsorption of water molecules was mitigated over Pd/MnO 2, while the desorption of O 2 2– intermediate was accelerated, as identified by H 2 O-TPD and in situ diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy studies. These findings highlight the Pd/MnO 2 –HAC catalyst as a robust and moisture-tolerant solution for ozone decomposition, demonstrating significant potential for practical environmental applications.