Visualization of SO2 induced low-temperature SCR catalyst deactivation and regeneration

Abstract number
European Microscopy Congress 2020
Corresponding Email
[email protected]
PSA.8 - Microscopy in industrial applications
Prof. Hangsheng Yang (1)
1. Zhejiang University

In situ ETEM, Low temperature, selective catalytic reduction, SO2 resistance, steric hindrance

Abstract text

Fossil fuels are and will still be the dominant source of energy in the world. But fossil fuels combustion inevitably emits nitrogen oxides (NOX). NOX are one series of the major air pollutants which cause a series of environmental issues (such as smog, acid rain, and ozone depletion) and are harmful for human health. In order to control NOX emission, the application of post-combustion technology is essential, especially selective catalytic reduction is widely applied in power plants using V2O5-WO3-TiO2 as catalysts and NH3 as reductant. To remove NOX from low-temperature flue gases (in steel, cement, glass, and other important industries), however, remains challenging since the catalysts are severely deactivated by trace SO2 [1].

Here, by using in-situ ETEM, we successfully observed the interaction between SO2 and CeO2 nanorod catalyst in atomic scale and found a dynamic equilibrium between sulfate deposition and decomposition (Fig. 1), which provided a new approach to solve the catalyst deactivation by establishing this dynamic equilibrium at temperature as low as 250 ℃. In the meantime we also studied the steric hindrance effects of the surface ammonia (bi)sulfate network by DFT, and finally developed a MnOX/CeO2 catalyst which showed almost no activity loss for 1000 hours test at 250 ℃ in the presence of 200 ppm SO2 [2].  

Figure 1. Schematic diagram of the proposed mechanism based on in situ ETEM.



[1] Li B., Ren Z., Ma Z., Huang X., Liu F., Zhang X., Yang H., Catal. Sci. Technol., 6 (2016) 1719-1725.

[2] Ma Z., Sheng L., Wang X., Yuan W., Chen S., Xue W., Han G., Zhang Z., Yang H., Lu Y., Wang Y. Adv. Mater., 31 (2019) 1903719.