文摘
Cerium-modified Cu-SSZ-13 catalysts were synthesized by an in situ hydrothermal method, and Ce was incorporated through ion exchange. The catalytic performance and N2 selectivity over prepared catalysts were evaluated in the selective catalytic reduction (SCR) of NOx by NH3. The physicochemical properties of the samples were characterized using XRD, SEM, H2-TPR, XPS, NMR, XAS, and N2 adsorption. The results indicated that Cu-SSZ-13 modified by Ce showed better NOx removal efficiency and aging resistance. The optimized condition was ion exchanged for 2 h in a cerous nitrate solution. The introduction of Ce effectively restrained the conversion of an active Cu component (Cu2+ → Cu+) during the hydrothermal aging. Ce3+ species strongly associated with molecular sieve carriers and only slight skeleton dealumination was observed on the sample exchanged for 2 h, thus resulting in the further stabilization of catalyst active centers, which consequently maintained the catalytic activity and antiaging ability.