Silicalite-1@Cu-ZSM-5 core-shell catalyst for N2O decomposition

•Silicalite-1@Cu-ZSM-5 is more active than conventional Cu-ZSM-5 in N2O decomposition.•Silicalite-1@Cu-ZSM-5 has more dimetric Cu+ upon thermal pretreatment in He.•Less O2 is adsorbed on Silicalite-1@Cu-ZSM-5.•Both factors contribute to the high activity of Silicalite-1@Cu-ZSM-5.

Silicalite-1 particles with an average size of 260 nm were used as seeds to prepare Silicalite-1@ZSM-5 core-shell crystals with sizes on the order of 500 nm. A Silicalite-1@Cu-ZSM-5 catalyst was then prepared by ion exchange with copper acetate. Upon appropriate pretreatment in He at 500 °C, the core-shell catalyst showed much higher activity in N2O decomposition than Cu-ZSM-5 prepared using commercial ZSM-5 as the precursor. Characterization of relevant samples was conducted employing N2 adsorption-desorption, XRD, ICP, XRF, SEM, TEM, XPS, CO-IR, H2-TPR, and O2-TPR. It was found that Silicalite-1@Cu-ZSM-5 has more dimetric Cu+ upon thermal pretreatment in He. In addition, less O2 can be adsorbed on Silicalite-1@Cu-ZSM-5. Both factors contribute to the much higher activity of Silicalite-1@Cu-ZSM-5. The effect of co-fed O2 and H2O vapor on the catalytic performance was also studied.

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