A Niobia-Ceria based multi-purpose catalyst for selective catalytic reduction of NO sub(x), urea hydrolysis and soot oxidation in diesel exhaust

We report about a novel niobia-ceria based catalyst that may be applied for the selective catalytic reduction (SCR) of NO sub(x) as well as the catalytic regeneration of diesel particulate filters (DPF) in diesel engines. The material proved to be active in model gas experiments for a series of important reactions in these processes: (1) the SCR of NO with NH sub(3), (2) the hydrolysis of urea to NH sub(3) and (3) the oxidation of soot. The catalyst was able to convert 72% NO already at 250 degree C and showed almost full NO reduction between 300 and 450 degree C. The new niobia-ceria exhibited a similar urea hydrolysis activity as compared to a conventional TiO sub(2) catalyst. A significant decrease of the soot oxidation temperature was also noticed with this catalyst.