Abstract:
A series of monolithic cordierite-based Ce-Fe/Al
2O
3 catalysts were prepared by sol-gel and impregnation method. The selective catalytic reduction of NO with C
3H
8 over the catalysts were experimentally studied. Results indicated that when the addition of cerium increased from 1% to 5%, the C
3H
8-SCR of Ce-Fe/Al
2O
3/cordierite increased at first then decreased and 3.5Ce-Fe/Al
2O
3/cordierite showed the highest C
3H
8-SCR activity with 96.5% NO reduction in the presence of oxygen at 600℃. Cerium was able to improve the resistance to SO
2 in the flue gas for the Fe/Al
2O
3/cordierite catalysts. When 0.02% SO
2 was fed into the flue gas during the test, the NO reduction by 3.5Ce-Fe/Al
2O
3/cordierite with C
3H
8 was always kept at about 93%, while the NO reduction by the catalyst without Ce, i.e., Fe/Al
2O
3/cordierite, decreased from 88% to 80%. The catalysts were characterized using XRD, N
2 adsorption-desorption, SEM, H
2-TPR and Py-FTIR spectra of adsorbed pyridine. Results showed that the addition of cerium to iron oxide could form the solid solution, which could increase the Lewis acid concentration and redox property of the catalyst, thus improving the performance of catalytic reduction of NO with C
3H
8. However, the introduction of too much cerium would reduce the crystallinity of iron oxide nanorods, then inhibited the formation of the NO
2/NO
3- species in the C
3H
8-SCR reaction, resulting in a decrease in the efficiency of NO reduction.