Catalytic activity and stability of a Cr modified Co–Fe LDO catalyst in the simultaneous catalytic reduction of NOx and oxidation of o-DCB

Abstract

In this paper, a Co–Fe LDO catalyst was prepared by combining K₂Cr₂O₇ and Cr(NO₃)₃ to modify the LDH precursor. The catalytic activity of NOx and o-DCB was systematically studied, and the effect of gas composition on the catalytic activity was investigated. The prepared Cr (0.25)/Co–Fe LDO catalyst showed the best catalytic performance, with conversion efficiencies of NOx and o-DCB of 89.0% and 81.6% at 250 °C, respectively. The catalysts were characterized by XRD, BET, SEM, XPS, H₂-TPD and NH₃-TPD to explore the reaction activity. In addition, the interaction between NH₃-SCR and o-DCB oxidation was investigated by changing the gas atmosphere. The results showed that the inhibition at low temperature (< 200 °C) could be attributed to the residues of the by-products of incomplete oxidation. The further oxidation of NO to NO₂, and the dissociation of NH₃ are the reasons for the mutual promotion of the two reactions in the middle and high temperature sections. Water vapor has little effect on the reaction and the introduction of SO₂ will cause irreversible inactivation of the catalyst.