FeSiBEA zeolite with 0.8 Fe wt% is prepared in acidic condition (pH 2.5) by a two-step postsynthesis method which allows to incorporate iron into framework of zeolite as mononuclear distorted tetrahedral Fe(III) species, as evidenced by XRD, diffuse reflectance UV-vis and X-ray absorption spectroscopy. The single site FeSiBEA catalyst with isolated and framework Fe centres is active in SCR of NO process with C2 (ethanol and ethylene) reducing agents, with selectivity towards N2 exceeding 90% in the broad temperature range from 573 to 723 K for maximum NO conversion about 50 and 30% at 573 K for ethanol and ethylene respectively. In contrast, this catalyst is much less active with C1 (methanol and methane) reducing agents, with maximum selectivity towards N2 not exceeding 65% with methanol and 10% with methane for maximum NO conversion of 10 and 23% respectively. The low activity in CH4-SCR of NO on Fe0.8SiBEA catalyst containing only isolated mononuclear distorted tetrahedral Fe(III) species in the framework zeolite could be explained by high energy of Csingle bondH bond, which should be broken to activate methane molecule.