The synergistic effects of cerium presence in the framework and the surface resistance to SO2 and H2O in NH3-SCR

Mn-Ce/CeAPSO-34 was prepared, in which cerium was incorporated in the SAPO-34 framework through using a one-step hydrothermal method, while manganese and cerium were supported on the surface by the Ethanol dispersion method. The conversion of NOx in selective catalytic reaction with NH3(NH3-SCR) over Mn-Ce/CeAPSO-34 catalyst reached nearly 97.7% at 140 °C and remained about 100% in the temperature range of 160-240 °C. Besides, the synergistic effects of cerium in the framework and the surface on the resistance to SO2 and H2O in low-temperature NH3-SCR were investigated. The results demonstrated that a strong synergistic effect existed in Mn-Ce/CeAPSO-34 catalyst, which showed outstanding SO2 tolerance and H2O resistance. At the same time, the structural properties and possible metal-support interaction of the catalysts were characterized by XRD, SEM, H2-TPR, XPS and TG-DSC. According to the characterization results, Ce could inhibit the deposition of NH4HSO4 on the surface of the catalysts and preferred to react with SO2, hence protecting the manganese active sites. Meanwhile, the theoretical results of DFT calculations suggested that Ce site supported on the surface neighbored by Ce site in the framework was more capable of reacting with SO2.