(560gh) Metal Oxide Catalysts for Low Temperature NOx Adsorption | AIChE

(560gh) Metal Oxide Catalysts for Low Temperature NOx Adsorption


Siddavaram, R. K. - Presenter, University of Michigan
Chen, X., University of Michigan
Schwank, J., University of Michigan
The increasing efficiency of automotive engines has resulted in lower exhaust temperatures. Such improvements call for enhanced after-treatment systems to mitigate NOx emissions, particularly in the cold start period with the exhaust temperature in the range of 100-200 oC. However, the state-of-art commercial deNOx catalysts for diesel vehicles are only effective at temperatures above 200 oC. This work tries to formulate a catalyst which can adsorb and store NO in the form of metal-nitrates below 200 oC and subsequently release NO2 in 200-400 oC regime, where commercial deNOx catalysts eliminate it effectively. Thermogravimetric analysis results show that nitrates of copper, cobalt and lanthanum supported over alumina are stable at temperatures below 200 oC, but totally decomposed to NO2 in the 200-400 oC window. This indicates the potential application of these base metal oxides in NO adsorption at low temperatures. In order to accelerate the adsorption of NO and transformation to metal-nitrates at low temperatures, an additional active metal which oxidizes NO to NO2 will be combined with alumina supported copper oxide, cobalt oxide and lanthanum oxide. The insights drawn from this study will be useful in the design of low-temperature NO adsorption catalysts formulated with base metals.