Development of de-NOx Catalyst for the Control of NOx Emissions from Lean-Burn Gasoline Engines

Catalytic performance of some non-noble metal based catalytic materials has been investigated for de-NOx reactions, under normal and lean conditions. These catalysts show significant catalytic activity for NOx conversion by hydrocarbon even in presence of oxygen, while the high de-NOx activity with CO was found to be severely affected in oxygen. The surface area of catalysts has been improved following their synthesis on high surface area alumina, using special preparative techniques. These catalysts show excellent thermal stability, while their light-off characteristics have also been remarkably improved by proper application of commonly used high surface area alumina. A small amount of ruthenium metal incorporation has been found very useful with regard to their de-NOx activity and light-off characteristics. Their catalytic activity in presence of oxygen and, at reasonable space velocities, deserve attention for the further investigations on these type of materials, for their possible applications in NOx control under lean-burn conditions. It is realized that perovskite type and other non-noble metal based materials can be suitably designed for de-NOx reactions under lean conditions. Further studies on improvement of catalytic activity, development of modified catalyst compositions, their evaluations with different hydrocarbons as reducing agents are proposed, to investigate their performance and durability for lean burn gasoline vehicle exhaust.