Size controlled ZSM-5 on the structure and performance of Fe catalyst in the selective catalytic reduction of NOx with NH3

•ZSM-5 with different morphologies and sizes were prepared.•Fe/ZSM-5 catalyst showed above 90% NOx conversion at 280–650 °C.•ZSM-5 with cauliflower-like morphology promoted the distribution of isolated Fe3 +.•The isolated Fe3 + in Fe/ZSM-5 catalyst was the main active sites in NH3-SCR.

Fe/ZSM-5 catalysts with various morphologies and sizes were prepared and the catalytic properties in NH3-SCR were also investigated. The different ZSM-5 morphologies and sizes indeed influence the dispersion of Fe species. The Fe/ZSM-5 catalyst, which was cauliflower-like morphology of ZSM-5 support aggregated by small nano-crystal zeolite with crystallite size of about 50 nm, exhibited the best NH3-SCR activity (T≥ 90% = 280–650 °C). This specific morphology and size of ZSM-5 support were considered to benefit the distribution of isolated Fe3 + species, which was proved to be the main active sites in SCR reaction.