초록 ▼

The exhaust gases, such as of an internal combustion engine are contacted with a catalyst containing copper in the presence of hydrocarbons in an oxidizing atmosphere, whereby nitrogen oxides are reduced from the exhaust gases. Then, the exhaust gases are preferably contacted with an oxidizing catal

The exhaust gases, such as of an internal combustion engine are contacted with a catalyst containing copper in the presence of hydrocarbons in an oxidizing atmosphere, whereby nitrogen oxides are reduced from the exhaust gases. Then, the exhaust gases are preferably contacted with an oxidizing catalyst. The former catalyst contains copper loaded on a porous support formed from alumina, silica, silica-alumina or zeolite or mixture thereof. The support is preferably a monolithic body having a first portion loaded with copper and a second portion loaded with a metal or metals defining the oxidizing catalyst.

대표청구항 ▼

A method of purifying exhaust gases from an automobile engine supplied with a lean fuel-air mixture having an air-fuel ratio of at least 18:1 and having a higher ratio of air to the fuel and containing a greater amount of oxygen than is required for the complete combustion of any unburned fuel, said

A method of purifying exhaust gases from an automobile engine supplied with a lean fuel-air mixture having an air-fuel ratio of at least 18:1 and having a higher ratio of air to the fuel and containing a greater amount of oxygen than is required for the complete combustion of any unburned fuel, said exhaust gases containing nitrogen oxides in an oxygen containing oxidizing atmosphere containing also hydrocarbons and CO, comprising the catalytic step of contacting the exhaust gases with a catalyst containing copper in the presence of hydrocarbons in an amount sufficient to satisfy the stoichiometric requirement for converting the nitrogen oxides to N2 in the oxidizing atmosphere, thereby reducing the nitrogen oxides from the exhaust gases to N2, while retaining residual hydrocarbons and CO, the oxiding atmosphere being one produced solely by the lean fuel air mixture and in which oxidizing atmosphere the amount of oxygen present in the exhaust gases as they are produced is greater than that required for oxidizing the existing reducing substances to H2O and CO2, wherein said copper is loaded on a porous support, and, wherein said porous support is formed from zeolite.