Abstract:

Cu-SSZ-13 catalysts had been prepared by using a microwave irradiation (MW) method and a conventional hydrothermal (CH) method, which were applied to removal of NO_x from diesel vehicles by NH₃. The physical and chemical properties of the samples were characterized by X-ray diffraction (XRD), N₂ adsorption-desorption, H₂ temperature-programmed reduction (H₂-TPR), electron paramagnetic resonance (EPR), NH₃ temperature-programmed desorption (NH₃-TPD), inductively coupled plasma-mass spectroscopy (ICP-MS), and X-ray photoelectron spectroscopy (XPS). The MW had some significant advantages, greatly shortening the crystallization time of SSZ-13 and improving its physical and chemical properties. The sample synthesized using MW with a crystallization time of 9 h had similar crystallinity to that synthesized by the CH with a crystallization time of 72 h. The sample synthesized by the MW had improved pore structure and amounts of Lewis (L) acid and Brönsted (B) acid. The great increase in Cu load as an active component indicated that the MW enhanced the ability of SSZ-13 to perform Cu exchange. The Cu-SSZ-13 synthesized by MW had improved low-temperature activity and anti-aging ability.

Key words: Microwave irradiation method, Conventional hydrothermal method, Cu-SSZ-13, DeNO_x, Hydrothermal aging