Simultaneous removal of SO2 and NOx with OH from the catalytic decomposition of H2O2 over Fe-Mo mixed oxides

In this paper, the simultaneous removal of SO 2 and NO x catalyzed by Fe-Mo mixed oxides at varying Mo/Fe atomic ratios was reported for the first time with the aim of reducing H 2 O 2 consumption and elucidating the roles of Fe and Mo species in the catalytic process. Fe-Mo mixed oxides with varying Mo/Fe atomic ratios were synthesized and the catalytic performances were systematically studied. The catalyst with Mo/Fe atomic ratio of 2.0 exhibited the highest activity, with which removal efficiencies of 89.4 % for NO x and 100 % for SO 2 can be attained at extremely low H 2 O 2 dosage. Products analysis revealed that SO 2 was mainly removed via wet scrubber, while the adequate oxidation resulting from OH radicals was the prerequisite for NO x removal. The redox pair of Fe 2+ /Fe 3+ played a significant role in decomposing H 2 O 2 , while Mo species had double effect on catalytic activity. Higher Mo content resulted in abundant oxygen vacancies and stronger surface acidity, which favored OH formation. However, the excessive Mo content involved severe surface Mo enrichment and remarkably reduced the active sites of Fe species. The H 2 O 2 /Fe-Mo catalyst system showed excellent stability and had a promising prospect for simultaneously removing SO 2 and NO x in coal-fired flue gas.