The Synthesis, Characterization And Denitration Of A New Fe-CuOx/ZSM-5Catalyst

Nitrogen oxides (NOx) are one of the most important atmospheric pollutants. Fe/ZSM-5and Cu/ZSM-5catalysts are high-profile due to the high activity in the NH3-SCR of NOx.In this paper, Fe-CuOx/ZSM-5catalysts with different ratio of Fe and Cu were prepared by microwave-ultrasound impregnation method, and the NH3-SCR activity of these catalysts were tested on the fixed-bed, the experimental conditions:the space velocity (GHSV)5000h-1, the O25%, the NO1000×10’6,[NH3]:[NO]=1:1. It could be found that the catalyst with8.5%(wt) Cu and the Fe/Cu=2has the best NOx conversion which was higher than98%at the temperature range of1800-400℃X-ray diffraction spectrum (XRD) and other characterization methods were used to characterize the morphology and structure of catalysts, the electron transfer in the process of this reaction was also researched as an important influencing factor of the catalytic activity. XRD results indicated that a new phase of Fe2CuO4appeared when Fe and Cu were added to the catalyst together, and the peaks of FeOx and CuOx disappeared after microwave-ultrasound process; H2-TPR results indicated that the active components in the catalyst became easy to be reduced; BET results indicated that ultrasound make the specific surface area of the catalyst decreased, it may because that the open-framework structure was be changed after ultrasound; NO-TPD results indicated that more NO was absorbed to the catalyst with the appearance of Fe2CuO4; TEM results indicated that cavitation bubble was found in the TEM images and the active components were disappeared on the surface of ZSM-5well-proportioned; the integrated analysis of EPR、 XPS and FT-IR indicated that the electron transfer between Cun+and Fen+which existed in the process of NH3-SCR play a very important role in the conversion of NOx.XPS analysis were used to trace the changes of the metal valence before and after the SCR reaction and found it have a significant impact.