Modification of manganese oxides for enhancing ozone catalytic decomposition under moist conditions

Abstract

Mn-based catalysts modified by copper, alumina and/or rGOs were synthesized by a simple coprecipitation method to decompose ozone under high humidity conditions, and their intrinsic mechanisms of ozone decomposition were investigated deeply. Hereinto, Mn-based catalysts doped by Cu-Al and Cu-Al-rGOs exhibited excellent activity and durability, maintaining above 94% and 98% ozone conversion for nearly 40 h under 85% RH and GHSV of 300 L·g−1·h−1 at 25 °C. The characterization results showed that the Cu dopants enhance the reducibility and regeneration speed owing to the formation of CuMn2O4 solid solutions, and the additions of Al and rGO significantly increase the amount of surface and sub-surface lattice oxygen, promoting effectually catalytic performances. XPS results revealed that the abundant surface oxygen species with high reactivity and stability were generated from the sites associated with Cu–O, Al–O bonds, and large amounts of Mn2+/Mn3+ in Mn-based catalysts modified by Cu, Al and GOs.