Mn_yCo_3−yO_x bimetallic oxide prepared by ultrasonic technology for significantly improved catalytic performance in the reduction of NO_x with NH₃

NO_x emission is a major environmental issue. Selective catalytic reduction (SCR) is the most effective method for the conversion of NO_x in flue gases to harmless N₂ and H₂O. In this work, a series of Mn-Co mixed metal oxides, Mn_yCo_3−yO_x, are intentionally prepared by an ultrasonic technology followed by a hydrothermal treatment, and their denitration (de-NO_x) performances are evaluated by the SCR reaction in the presence of NH₃. The results show that the SCR de-NO_x performance of Mn_yCo_3−yO_x is significantly improved compared with single metal oxide (MnO_x or CoO_x). The reason can be ascribed to a strong interaction between MnO_x and CoO_x, which reduces the crystallinity of Mn_yCo_3−yO_x catalysts, increases the specific surface area, builds the redox cycle of Co³⁺ + Mn³⁺ ↔ Co²⁺ + Mn⁴⁺, improves the reducibility, enhances the surface acid sites, accelerates the reaction between the adsorbed NO_x species and the coordinated NH₃ bound to the Lewis acid site, resulting in a significant improvement in the SCR de-NO_x performance. The work provides us with a thought to improve the de-NO_x performance by building a strong interaction between catalyst components.