In-situ DRIFTS investigation on the selective catalytic reduction of NO with NH3 over the sintered ore catalyst

In this study, the sintered ore used as catalysts for the selective catalytic reduction (SCR) of NOX with NH3 from the sintering flue gas was investigated. The experimental results demonstrated that the maximum denitration efficiency, about 61.64%, occurred at 300 °C, 1.0 NH3/NO ratio, and 1000 h−1 gas hourly space velocity (GHSV). In order to understand the SCR denitration mechanism, the catalyst was characterized by DRIFTS, XPS, H2-TPR, BET and ICP-MS. It was found that there were Lewis and Brønsted acid sites at the surface of the sintered ore, which lead to the appearance of amide species (NH2), NH4+ intermediates, gaseous or weakly adsorbed NO2 and nitrite species. Hence, it was concluded that the reaction of the amide species (NH2) with gaseous NO (E-R mechanism) and the reaction of absorbed NO2 with the coordinated ammonia (L-H mechanism) were attributed to NOx reduction.