Catalytic Degradation of Acetone by AMn₂O₅ Based on A-Site Substitution

In order to systematically understand the relationship between the structure and catalytic performance of the AMn(2)O(5) mullite catalyst, five kinds of A-site cation (La3+, Nd3+, Gd3+, Sm3+, and Y3+) manganese mullite catalysts were prepared for acetone degradation. XRD characterization results show that all catalyst samples successfully formed a pure-phase mullite structure. SEM, H-2-TPR, O-2-TPD, and other characterization results show that the morphology and redox properties of the catalyst strongly depend on the A-site elements, and the cationic effects of different A-sites have a significant impact on the catalytic activity. The activity sequence of the AMn(2)O(5) catalyst for acetone degradation is SmMn2O5 > LaMn2O5 > YMn2O5 > NdMn2O5 > GdMn2O5. Compared with the other four catalysts, SmMn2O5 shows a higher Mn4+/Mn3+ molar ratio and abundant Oads content, excellent reactive oxygen species desorption capacity, strong reduction, large specific surface area, and other advantages, which are conducive to the catalytic oxidation of acetone gas. On the basis of the best active catalyst SmMn2O5, the study shows that the preparation method of the catalyst and the addition of active agent F-127 also have an important influence on the activity of the catalyst. In addition, in situ diffuse infrared Fourier spectroscopy was used to analyze the reaction intermediates of oxidized acetone, and the specific catalytic mechanism was discussed. This study provides an important experimental basis for making full use of the rare-earth cation effect, modifying and optimizing the AMn2O5 catalyst, and promoting catalytic oxidation of acetone.