This paper focuses on the NO reduction by ammonia via FeSO4 catalyst supported by molecular sieve in a fixed bed reactor at 400℃.The experimental results indicate that the catalyst has immediate catalytic effect on NO reduction.Due to its improved physical structure

the catalyst improves the NO reduction rate by 20% compared with pure FeSO4.The effects of preparation conditions on catalytic activity

including the mix ratio

impregnation agent and impregnation time etc.

are investigated. Mossbauer spectroscopy is used for the study.It is found that Fe2+ is oxidized to Fe3+ during the preparation and most FeSO4 is transferred to Fe(OH)SO4 and Fe2O (SO4)2.Fe(OH)SO4 is better than the other speices in NO reduction and the ratio of different species is related to the water and oxygen content in atmosphere.The results of in-situ FTIR indicate that Fe is the reaction centre.NH3 is absorbed on the catalyst and reacts with NO

which can be explained by Eley-Rideal mechanism.Compared with other commercial catalysts

FeSO4 demonstrates great industrial potentials because of its low cost and excellent catalytic effect at high space velocity.