H2-SCR at low temperatures on noble metal supported catalysts

The selective catalytic reduction of NO using hydrogen as reducing agent (H2-SCR) is investigated on alumina supported noble metal catalysts at low temperatures (<350°C). Three noble metal supported catalysts (Pt/Al2O3, Pd/Al2O3, and Rh/Al2O3 with 1 wt.% metal loading), prepared by the incipient wetness impregnation method, were characterized by N2 adsorption-desorption at −196°C, NO-TPD, and H2-TPD. Catalytic activity tests of the investigated noble metal catalysts were performed under plug flow conditions, using a feed stream of 0.5% NO, 0.60% H2 and Ar as balance gas, at temperatures below 350°C, and a GHSV of 4500 h−1. Pt/Al2O3 and Pd/Al2O3 proved to be the most active catalysts for H2-SCR in terms of NO conversion, while the Pd catalyst showed the best N2 selectivity and N2 yield. NO conversion > 95% and N2 selectivity above 80% were obtained for each catalyst at 200°C.