In the present study, the reduction of NO by two activated carbons without and loaded with Fe based catalysts was studied at 300 degrees C using a fixed-bed reactor. The activated carbon samples impregnated with and without the catalysts were characterized using TGA, SEM, gas adsorption, ICP-AES, XPS and XRD. The experimental results showed that neither of the raw activated carbons achieved the required denitrification performance. However, compared with coal derived activated carbon (C-0), biomass derived activated carbon (B-0) performed better. The denitrification efficiency improved with the O-2 content in the flue gas, achieved a maximum approximately at 3% O-2, and then decreased with further increase in the O-2 content. The effect of the metals loaded and addition amount of the catalysts was then examined in detail with the biomass derived activated carbon. At the same dosage of catalysts, the biomass derived activated carbon impregnated with K ions was apparently more efficient than it counterpart loaded with Fe ions. A higher addition rate of Fe was required in order to be efficient in NO conversion. Addition of K was further found to significantly improve the NO conversion efficiency of the biomass activated carbon loaded with 3% Fe which otherwise showed a sharp premature decrease in NO conversion efficiency immediately after the flue gas was introduced. Finally the effects contributing to the synergetic effect of Fe and K are discussed. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.