초록 ▼

A three-way catalyst is described for the purification of automobile exhaust gases formed of an active substance of platinum and rhodium and possibly base metal(s) at a certain weight ratio between the two noble metals and at a certain atomic ratio between the noble and the base metal, which are pre

A three-way catalyst is described for the purification of automobile exhaust gases formed of an active substance of platinum and rhodium and possibly base metal(s) at a certain weight ratio between the two noble metals and at a certain atomic ratio between the noble and the base metal, which are precipitated onto active aluminum oxide containing certain quantities of CeO2, ZrO2 and Fe2O3, and whereby the catalyst is obtained by impregnating active aluminum oxide, possibly stabilized with alkaline earth metal, with a solution of cerium, zirconium and iron salt which is thereupon calcined in air at 500°-700°C. and then treated after application of an impregnation of salts of the active substance components in a gas current containing hydrogen at temperatures below 650°C.

대표청구항 ▼

A catalyst for simultaneous oxidation of carbon monoxide and hydrocarbons and reduction of nitric oxides in exhaust gases of internal combustion engines, comprising (a) 0.03-3% by weight of a platinum and rhodium containing active phase with a weight ratio between platinum and rhodium of 2:1-20:1;

A catalyst for simultaneous oxidation of carbon monoxide and hydrocarbons and reduction of nitric oxides in exhaust gases of internal combustion engines, comprising (a) 0.03-3% by weight of a platinum and rhodium containing active phase with a weight ratio between platinum and rhodium of 2:1-20:1; (b) 5-15% by weight of a mixture of CeO2 and ZrO2, whereby these oxides are at weight ratios of 20-80:80-20; (c) 1-10% by weight of Fe2O3 as well as (d) a residual quantity up to 100% by weight of aluminum oxide of the transition series and obtained by impregnating a carrier material of Al2O3 of the transition series, with an aqueous solution containing cerium, zirconium and iron salts or, mixing the carrier material with the respective oxides of cerium, zirconium and iron, tempering for 30-180 minutes in air at 500°-700°C. thereupon impregnating the carrier with an aqueous solution of a salt of platinum and a salt of rhodium, drying and subsequently treating in a gas current containing hydrogen at temperatures 250°-650°C.