Effect of Preparation Methods on Structure and Properties of Mn-La Catalyst for Low Temperature NH3-SCR

Mn-La catalysts were prepared by solid-state reaction (SSR) and co -precipitation methods (CPM). The effects of preparation methods on denitration and SO2/H2O resistance of the catalysts were investigated. The structure and physicochemical properties of the catalysts were characterized by XRD, BET, H-2-TPR, NH3-TPD and XPS. The results show that La doping decreases the crystallinity of MnOx and increases the specific surface area and pore volume of MnOx. The bond cooperation of Mn-O-La promotes the dispersion of Mn on the catalyst surface, while the highly dispersed Mn are easier to be reduced. The reduction temperature of the catalyst moves to lower temperature, and the redox ability is improved. After La doping, the amount of Bronsted acid and total acid increase on the catalyst surface, and the concentration of Mn4+ and the surface chemisorption oxygen also increase. Therefore, La doping is beneficial to the denitration activity of the catalyst. The results of reaction evaluation show that MnLa-CPM catalyst exhibits the best denitration efficiency, which is close to 100% at 80 degrees C. In the presence of H2O and SO2, the denitration efficiency of MnLa-CPM catalyst can still reach 80%, showing good SO2/H2O resistance performance.