Lean NOx reduction in real diesel exhaust with copper and platinum titania based monolithic catalysts

A study on the catalytic behaviour of a copper and a platinum titania based monolithic catalyst in the reduction of nitrogen oxides with hydrocarbons in real diesel conditions was carried out. A Volvo TD 7.31 engine was used as gas source, and diesel fuel was the reductant. In these conditions, both catalysts were active in the reduction reaction. The influence of various operating parameters on the catalytic activity, as engine speed and reductant concentration in the gas has studied. Other aspects were also studied as selectivity of reduction to nitrous oxide, nitrogen monoxide oxidation into nitrogen dioxide, and generation of carbon monoxide. The selectivity in the reduction of NO to N2O with the diesel exhaust was relatively low with both titania supported systems. Opposite behaviours of both catalysts in NO to NO2 oxidation were observed, indicating two different mechanisms for this reaction. (C) 1999 Elsevier Science B.V. All rights reserved.