OMS-2 molecular sieves doped with ceria for the development of new emission control catalyst

Manganese oxide octahedral molecular sieves (OMS) are microporous, inorganic nanostructures. Manganese oxides with cryptomelane type structures (OMS-2), has a onedimensional tunnel structure composed of edge shared MnO6 octahedra that form a 2 x 2 arrangement. OMS-2 materials are hydrophobic and hence have improved hydrolytic stability under oxidation conditions. The mixed valency in OMS-2 contributes to its highly active and selective catalysis. Functionality of OMS-2 can be further extended by structural incorporation of various dopants. In this work we have synthesized a range of OMS-2 based supports doped with Ce, CeZr and Pt for emission control. Materials often used for emission control applications are precious metals supported on a Ceria Zirconia mixed oxide. Currently, one of the main challenges is to provide a catalyst which is active at low temperature, due to the high emissions of combustion engines during cold start cycles. In particular, we have investigated the use of these OMS-2 hybrid catalyst supports for their activity in the oxidation reactions of CO, C3H6 and CH4 and compared with a commercial diesel oxidation catalyst. The new catalyst samples were tested under representing those in the catalytic filter of a light duty diesel vehicle. The effect of doping the OMS-2 support with Ceria and Zirconia have been studied both pre and post loading with 1wt% Pt.