Catalytic Decomposition of Ozone in Ground Air by Manganese-Based Monolith Catalysts

Abstract

A highly active manganese dioxide material with deficient oxygen atoms (MnOx, x = 1.6–2.0) was prepared by calcining man-ganese carbonate, and a SiO2-Al2O3 support with large surface area was prepared by the peptizing method. A series of Pd-MnOx/SiO2-Al2O3 catalysts for ozone (O3) decomposition with different MnOx contents were prepared by incipient wet impregnation and characterized by activity tests, N2 adsorption, and life tests. The results of activity tests indicated that catalytic performance increased with MnOx content, but the MnOx catalyst without the support fell off easily and its catalytic performance decreased. At gas hourly space velocity (GHSV) = 360000 h−1, the complete conversion temperature (T100) on the Pd-MnOx/SiO2-Al2O3 catalyst with 80% MnOx content was 30 °C. At GHSV = 660000 h−1, the catalysts with 80%–90% MnOx had the best performance with T100 = 45–50 °C. Touching temperature between air and the water tank of an automobile was satisfied in this temperature range. At 45 °C and GHSV = 510000 h−1, O3 conversion on the catalyst with 80% MnOx still kept better standard (>90%), which indicates that the catalyst had very high capacity to resist deactivation after 95 h of life test.