Effects and mechanism of Fe loading and sulfuric acid concentration on selective catalytic activity of SO42−-CeCO3F-CePO4

Abstract

BackgroundA denitration catalyst with superior performance was prepared by loading Fe and sulfuric acid treatment, and its reaction mechanism was studied. MethodsThe transition metal Fe was loaded on SO42−-CeCO3F-CePO4 to prepare NH3-SCR denitration catalyst by impregnation. The best performing catalyst was explored by varying the loading ratio of Fe and the concentration of sulphuric acid. Significant findingsIn the range of 300∼400 ℃, the denitration rate reaches more than 90 %. The denitrification activity reaches 91.3 % at 350 ℃, and it has close to 100 % N2 selectivity at 100∼400℃. Appropriate concentrations of Fe and sulfuric acid can promote the full functioning of Ce on the surface of the support, exposing more strongly acid sites. The active substances such as Ce oxide, Fe oxide and Fe sulfate produced on the surface are better dispersed, which can provide more active sites and increase the reaction rate. Brønsted acid site generated by the P-O bond of phosphate in CePO4 was the main active site. At 350 ℃, the catalyst surface followes both the E-R mechanism and the L-H mechanism, and the two mechanisms participated in the denitration reaction.