The reaction of NO + C3H6 + O2 over the mesoporous SBA-15 supported transition metal catalysts

A series of mono-functional M/SBA-15 (M = Cu, Fe, Cr, and Al) and bifunctional M′/SBA-15 (M′ = Cu–Al, Fe–Al, and Cr–Al) catalysts was prepared via an incipient wetness impregnation, and further characterized by N2 adsorption, XRD, TEM, H2-TPR, Al27-NMR, and XPS as well as activity test for C3H6 + NO + O2 reaction. Ordered mesoporous structure of SBA-15 was well maintained even after impregnating the various metallic components. The deNOx activities of investigated catalysts follow a trend of Cu–Al/SBA-15 > Cu/SBA-15, Fe/SBA-15 > Cr–Al/SBA-15 > Cr/SBA-15 ≫ Fe–Al/SBA-15, Al/SBA-15 > SBA-15. Synergistic effect between copper and alumina was achieved showing a satisfactory NO conversion of approximately 80% over Cu–Al/SBA-15 at temperature as low as 350 °C under an atmosphere of 3000 ppm NO, 3000 ppm C3H6, 1% O2 and GHSV of 60,000 h−1. The SCR performance was found to be strongly correlated to the redox properties of tested catalysts, essentially chemical nature of supported metals, and surface density of active metallic species.

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► Copper or aluminum loading effectively enhances the NO conversion for bare SBA-15.
► Al presence is beneficial for suppressing the formation of CuO cluster and promoting the redox properties of Cu2+ species.
► Al nuclei have been mainly incorporated into the SBA-15 framework with the assistance of copper loading.
► A synergetic effect is achieved between copper and aluminum, resulting in an optimal performance over Cu–Al/SBA-15 showing NO conversion of ∼88% at 400 °C.