Reaction of NO with soot over Pt-loaded catalyst in the presence of oxygen

NOx and particulate matter are the main environmental hazards in the diesel exhaust. In order to explore a suitable method to remove NOX as well as particulate matter, we have examined the catalytic reduction of NOX with soot in the presence of oxygen. Pt catalyst loaded on Al2O3-coated honeycomb was found to be more active than K, Ca and Cu catalysts. Even in the presence of 8% O2, NO can be reduced to N2 by soot with Pt catalyst. NO was completely converted to N2 in the isothermal reaction at 500°C, and the high activity of the catalyst retained for a long time period. The effects of Pt catalyst and O2 on the mechanism of C-NO reaction was examined by using step response experiment.