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A system for NO removal from flue gas comprising partial oxidation by H 2 O 2 and selective catalytic reduction (SCR) process is proposed in this study. This hybrid system is found to be extremely efficient for deNO x at 200−290 °C. In this system, H 2 O 2 partially oxidizes the NO molecules to NO 2 . The NO/NO 2 mixture reacts fast with NH 3 on the surface of a V 2 O 5 −WO 3 /TiO 2 catalyst. The reaction kinetics was studied by varying reaction temperatures and the H 2 O 2 /NO molar ratio. A V 2 O 5 −WO 3 /TiO 2 SCR catalyst was also filled in the oxidation reactor, but it hardly changes the oxidation rate. The downstream SCR reaction was found to be significantly upgraded by the preoxidation process, which elevates the NO x reduction rate from 20% (without preoxidation) to more than 60% (with preoxidation).

In this work, a multifunctional filter with the abilities of particle filtration and NO x removal was fabricated using a combined particle filter for retreating waste catalysts through an impregnation method. By applying the fast selective catalytic reduction (SCR) method, the catalytic filter exhibited a high denitration activity (93.5% at 230 °C) and high sulfur resistance in the low-temperature area. Further investigations were carried out using X-ray fluorescence spectrometry, temperature-programmed ammonia desorption, temperature-programmed hydrogen reduction, and scanning electron microscopy (SEM) to characterize the catalysts and filter. The results showed that after retreatment, the toxic substances such as Na\K on the surface of the waste catalyst were removed, and the acidity of the catalyst was enhanced. This was the reason for the resumption of activity. The existence of microporous membranes on the filter and good distribution of the catalyst in the filter were found by SEM analysis, which was helpful to understand its filtration and denitration performance.