Advanced Catalyst Coating Technology for Porous Substrates

The increasing demands and strict regulations in diesel emission control leads to an ever-increasing use of Diesel Particulate Filters (DPFs) in OEM applications. To accelerate the oxidation of soot particles collected in the DPF we have developed novel catalytic coatings with a variety of methods based on conventional and novel synthesis routes. The developed catalytic compositions exhibit significant direct soot oxidation as evaluated by reacting mixtures of diesel soot and catalyst powders in a thermogravimetric analysis apparatus (TGA). The catalyst compositions were further deposited on porous filter structures and were then evaluated on an engine bench with respect to their filtration efficiency, pressure drop behavior and soot oxidation activity under realistic conditions. Interestingly enough it is shown that the often-conflicting targets of high filtration efficiency, low pressure drop and high soot oxidation activity can be achieved simultaneously using the developed coating technologies.