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 (NO.sub.x). 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.