Alkali Carbonate Stabilized on Aluminosilicate via Solid Ion Exchange as a Catalyst for Diesel Soot Combustion

We report the successful preparation of alkali-carbonate-supported aluminosilicate catalysts for diesel soot combustion. From the views of practical feasibility as well as economic and environmental concerns, utilizing alkali metals is preferable for diesel soot combustion. We overcome the drawback that the alkali compounds used as catalysts are easily soluble in water. Na2CO3 was stabilized on sodium- and potassium-containing nepheline ((Na, K)-nepheline) with water tolerance. This result suggests that carbonates are stabilized on the supports with higher energy than hydration energy and van der Waals force by thermal treatment of K2CO3/Na-nepheline via solid ion exchange. Na2CO3 on the surface of thermally treated K2CO3/Na-nepheline is likely to be a catalytically active species for carbon black combustion as (Na, K) mixed carbonate. Na2CO3 stabilized on (Na, K)-nepheline is recovered by CO2, which is likely to be derived from catalytic action on combustion of carbon black.