Comparison of alkaline pre‐treatment of MFI zeolites for N2O decomposition: different zeolite sources

Abstract

AbstractThree MFI parent zeolites with different morphological properties by different synthesis method were adopted. Alkaline treatment using sodium hydroxide was introduced to modify the structure of MFI zeolites. After iron exchange, the catalytic performance of both parent and modified MFI zeolites were evaluated in the N2O decomposition. The physicochemical properties were systematically characterized with various technologies, such as N2 adsorption‐desorption, ICP, XRD, UV‐Vis, 27Al MAS‐NMR, TEM. The experiment results prove that the Fe‐modified MFI catalysts with alkaline pre‐treatment show much better catalytic activity than Fe‐exchanged parent MFI catalysts. The curves of catalytic activities could move to low temperature range by 50‒100 °C. Furthermore, in the presence of NO, the performance gap between Fe‐Seed‐M, Fe‐Solid‐M, and Fe‐Com‐M three samples is obviously reduced. Amongst, for the Fe‐Solid‐M sample synthesized by the solvent‐free method, 90% N2O conversion could be attained at 500 °C, which shows potential to be applied the real condition. It is believed the hierarchical properties and the removal of amorphous substance is beneficial to the diffusion of ion exchange process. Therefore, the increase of active iron sites contributes to the improvement of catalytic performance. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd