Acid treated Ce modified birnessite–type MnO2 for ozone decomposition at low temperature: Effect of nitrogen containing co-pollutants and water

In this study, HNO3 treated Ce modified birnessite–type MnO2 (CexMn-AT; x = 0.01,0.1,0.2,0.5) have been designed for decomposition of ozone at low temperature (20–40 °C) in the absence or presence of nitrogen containing co-pollutants and water. The best catalyst Ce0.01Mn-AT exhibits stable ozone conversion of 94 % in nearly dry air (300 ppm of ozone, RH = 0.7 %, GHSV = 1200 L/(g.h), 20 °C) in the presence of N2O5/HNO3 pollutants. However, the ozone conversion drops to 64 % for the undoped catalyst showing the beneficial role of cerium. Additionally, the Ce0.1Mn-AT catalyst shows a stable ozone conversion of 91 % after 5 h on stream in moist air (RH = 30 %, 30 °C) in the same operating conditions as before. The high tolerance of the best acid-treated catalysts to co-pollutants and water can be explained by the high density of acid sites and oxygen vacancies which facilitate the adsorption and decomposition of ozone and allow to minimize the amount of nitrogen containing adspecies which can affect the catalytic performances for ozone decomposition.