US Patent 7374729 Exhaust gas treatment catalyst

Provided are an exhaust treatment catalyst and an exhaust article containing the catalyst. The catalyst comprises:(a) a carrier;(b) a first layer deposited on the carrier, said first layer comprising substantially only at least one refractive metal oxide;(c) a second layer deposited on the first layer, said second layer comprising substantially only at least one oxygen storage component and at least one binder therefor; and(d) a third layer deposited on the second layer, said third layer comprising at least one layer of one or more platinum group metal components supported on a refractory metal oxide support.Optionally, a fourth layer is deposited on the third layer wherein the fourth layer comprises one or more platinum group metal components supported on a refractory metal oxide support. As a further option, an overcoat layer may be deposited on the third or fourth layer wherein the overcoat layer comprises a catalyst poison sorbent. Also provided are methods for preparing the catalyst and methods for monitoring the exhaust storage capacity of an exhaust article containing the catalyst.