SO2 resistant soot oxidation catalysts based on orthovanadates

Metal orthovanadates based on Fe, Al and Ce were prepared by co-precipitation and their structural, morphological and reduction properties were characterized by means of XRD, BET and temperature programmed reduction (H2-TPR). Catalytic soot oxidation was carried out with thermogravimetric analysis (TGA) and temperature programmed oxidation (TPO), respectively, to study the influence of the soot-catalyst contact (tight or loose) as well as the influence of SO2 contamination on the catalyst's activity. The catalysts were compared with CeO2 as reference material. Under tight contact mode, metal orthovanadates were able to oxidize soot at 466–483 °C while in loose contact mode their activity was close to that of CeO2. However, the former did not suffer an activity loss due to SO2 poisoning, which is attributed to less adsorptive interactions between SO2 and the vanadates as could be proven by FT-IR and Raman spectroscopy.