The influence of calcination temperature on the activity and SO2 tolerance performance of MnCeOx catalyst for NH3-selective catalytic reduction reaction
摘要
The MnCeOx catalysts were synthesized via the co-precipitation method, with calcination temperatures ranging from 300 to 850 °C. The results demonstrate that MnCeOx-350 °C catalyst exhibits the optimal NOx conversion rate within the reaction temperature range of 175–325 °C. To understand the reasons for the influence of calcination temperature on the performance of catalysts, four representative catalysts were chosen for detailed analysis: MnCeOx-300 °C, MnCeOx-350 °C, MnCeOx-650 °C, and MnCeOx-750 °C. The catalysts were characterized through various techniques including nitrogen physisorption analysis, X-ray diffraction, Raman spectroscopy, hydrogen temperature programmed reduction, ammonia temperature programmed desorption, X-ray photoelectron spectroscopy, and in situ diffuse reflectance infrared Fourier transform spectroscopy experiments. In addition, we assessed the water and SO2 resistance of these catalysts. The results demonstrate that the reason why MnCeOx-350 °C has good performance is not only because of its lower crystallinity and higher specific surface area but also because the catalyst can provide more Brønsted acid sites, higher content of Ce3+, Mn4+, and surface adsorbed oxygen. The synergistic effect between Mn4+ and Ce3+ is enhanced while the surface acidity is increased, which is conducive to the improvement of the denitrification performance of the catalyst at low temperatures.