초록

The invention is a three-way catalyst of active aluminum oxide, palladium, rhodium and cerium dioxide. If Al2O3 is present as bulk carrier, the catalyst contains 5-20% by weight CeO2 and if Al2O3 is present as a coating on a honeycombed, inert carrier, it contains 25-50% by weight CeO2.

대표청구항 ▼

A platinum-free three-way supported catalyst with an active phase applied to aluminum oxide of the transition series, said active phase consisting of 0.03-3% by weight palladium and rhodium with a weight ratio between palladium and rhodium of 1:1 to 20:1, said aluminum oxide having a cerium dioxide

A platinum-free three-way supported catalyst with an active phase applied to aluminum oxide of the transition series, said active phase consisting of 0.03-3% by weight palladium and rhodium with a weight ratio between palladium and rhodium of 1:1 to 20:1, said aluminum oxide having a cerium dioxide content of 25 to 50% by weight, whereby the weight amounts of noble metal, cerium dioxide and aluminum oxide constitute 100%, the active phase being present as a coating on a honeycombed, inert carrier support of ceramic or metal, the supported catalyst being obtained by a process comprising: depositing onto said honeycombed, inert carrier support the aluminum oxide, optionally latticestabilized, in the form of an aqueous suspension in which a cerium salt is dissolved in solution and which optionally additionally contains a cerium compound in solid form to thereby obtain a catalyst precursor A, drying and tempering said catalyst precursor A deposited on said carrier support in air at 300°-950°C., thereafter impregnating said catalyst precursor A with an aqueous solution of palladium- and rhodium salt to thereby obtain a catalyst precursor B, drying and finally tempering said catalyst precursor B at a temperature above 250°C., optionally in a gas stream containing hydrogen.