CATALYST FOR PURIFICATION OF EXHAUST GAS

摘要

PURPOSE: To provide a catalyst having NOx removal activity in a high temp. region by carrying rhodium on tungsten oxide. CONSTITUTION: Rhodium is deposited on tungsten oxide to obtain the objective catalyst. This tungsten oxide is known as a hydrogenation catalyst and it is known that olefin HC in exhaust gas has relatively high activity and paraffin HC has low activity. When NOx in HC-contg. exhaust gas is removed, the tungsten oxide acts like a hydrogenation catalyst to HC at the time of oxidation combustion of HC with the rhodium and converts high activity olefin HC into low activity paraffin HC or prevents sudden oxidation of HC. As a result, HC becomes a high activity reducing agent effective in decomposing NOx at a higher temp. and the catalyst has NOx removal activity in a higher temp. region.