Surface Modification of Cu-SSZ-13 with CeO2 to Improve the Catalytic Performance for the Selective Catalytic Reduction of NO with NH3

A series of Cu-SSZ-13@CeO2 catalysts with surface modification with CeO2 was prepared by the modified self-resemble method based on the one-pot synthesized Cu-SSZ-13 catalyst and applied for the selective catalytic reduction of NO by NH3. The low-temperature catalytic activity and the tolerance to SO2 + H2O of Cu-SSZ-13@CeO2 were found to enhance markedly compared with Cu-SSZ-13. In parallel, the XRD, N2-BET, H2-TPR, SEM, XPS, and in situ DRIFTS were performed to characterize the catalysts. XRD and SEM results proved that the surface of Cu-SSZ-13 was covered by nanoparticles of CeO2. XPS results further confirmed that Ce species were in the outer of the catalysts. N2-BET indicated that the physical structure parameters of the Cu-SSZ-13@CeO2 were changed obviously due to the coverage of CeO2. H2-TPR suggested that the redox properties of the Cu-SSZ-13@CeO2 catalysts were improved compared to the unmodified Cu-SSZ-13. In situ DRIFTS results demonstrated that the intensities of the bands attributed to NH3 and NOx species on the surface of Cu-SSZ-13@CeO2-2 enhanced due to the CeO2 modification, which played an important role for the NH3-SCR performance.