Abstract: The present invention is directed to an improved apparatus and method of minimizing catalyst poisoning by inorganic deposits from lube oil additives and particulate matter, especially in aircraft. More specifically, the present invention is directed to an air purification system comprising an upstream metallic foam trap and downstream converter, wherein the trap physically blocks inorganic deposits and particulate matter from poisoning the downstream catalysts. The present invention is also directed to a metallic foam trap containing a coat comprising a first metallic thermal arc sprayed layer and optionally a second refractory metal oxide.

Abstract: The invention pertains to a layered ammonia oxidation catalyst. The layered catalyst causes ammonia to be selectively oxidized in the presence of an oxidant such as air, while minimizing the formation of nitrogen oxides (NOx). The layered catalyst comprises a refractory oxide support such as gamma alumina upon which a platinum component is deposited and a vanadia component is deposited on the platinum. The catalyst is preferably disposed on a substrate such as a metal foil whose surface contains a “herringbone” pattern.