Selective Catalytic Reduction of NO x of Ship Diesel Engine Exhaust Gas with C3H6 over Cu/Y Zeolite

Various solid Cu-containing catalysts were prepared. Their performance in the selective catalytic reduction of NO x using propene as reducing agent from 150 to 450 °C in an O2-rich model exhaust gas in the presence of water vapor was investigated. This research aimed at the development of a catalytic NO x to N2 (DeNO x ) step to be part of a ship diesel exhaust abatement system in combination with other techniques, such as nonthermal plasma. Among the catalysts tested, Cu on zeolite Y with an optimized load of 16 wt % (denoted as 16Cu/Y) displayed excellent DeNO x activity with highest selectivity toward N2 at 290 °C. The influence of other variables, such as Cu load, calcination temperature, feed composition, and GHSV on the performance of 16Cu/Y was studied, as well. The highest N2 yield of 98% was achieved using 2000 ppm of propene in the gas feed. The presence of O2 proved to be a crucial factor for promoting the selective reduction of NO x with C3H6 over this catalyst. On the other hand, the presence of water in the feed decreased NO x to N2 conversion. However, the catalyst showed excellent stability over 120 h, even at high water concentration, and also after repeated heating from ambient temperature to 450 °C, and it was reusable after downtimes without remarkable loss in activity. The nature of the Cu species was studied by XPS, XRD, and TPR experiments.