Catalyst for purifying exhaust gas and method for purifying exhaust gas

摘要

A catalyst for purifying exhaust gas comprising crystalline iridium silicate having a Si/Ir atomic ratio of 50 to 800 and a Si/Al atomic ratio of not less than 15. The catalyst exhibits excellent activity and selectivity when used for purification of, and specifically for eliminating NOx from, an exhaust gas which contains reducing components including hydrocarbons, oxygen in excess of the stoichiometric quantity necessary for completely oxidizing all of the reducing components, and nitrogen oxides. The catalyst is highly durable to hydrothermal aging.