Montmorillonite based porous clay heterostructures modified with Fe (Fe-PCH) catalysts were prepared by ion exchange and impregnation methods, respectively. The PCH samples were characterized by XRD, BET, UV-vis, HRTEM, XPS, H-2-TPR, Py-FTIR, etc. The catalytic activity of the catalysts was evaluated for the selective catalytic reduction of NO with C3H6 with a fixed-bed reactor and the in situ DRIFTS study was conducted to investigate the reaction mechanism. It was observed that the catalysts prepared by impregnation methods were more reactive for the SCR-C3H6, e.g., 96% of NO conversion to N-2 was tested at 400 degrees C when 8.4 wt% iron was supported on the PCH. The results of catalyst characterization indicated that alpha-Fe2O3 nanorods formed in PCHs channels and (110) and (104) planes exposed. alpha-Fe2O3 nanorods promoted the formation of the Lewis acid sites. With the study of DRIFTS, a reaction mechanism was proposed, where the reaction intermediates were mainly inorganic nitrates, acetates, organic nitrogen compounds and isocyanate species.