| Autor: |
Zhang, Jianyi, Miao, Jifa, Huang, Biyi, Chen, Yanting, Chen, Jinsheng, Wang, Jinxiu |
| Zdroj: |
Industrial & Engineering Chemistry Research; February 2024, Vol. 63 Issue: 5 p2167-2176, 10p |
| Abstrakt: |
The poisoning of K2O, KCl, and K2SO4on commercial V2O5–WO3/TiO2catalysts used for selective catalytic reduction (SCR) of NOxby NH3was investigated, respectively. The degree of inactivation observed in these catalysts poisoned with different forms of potassium follows K2O ≈ KCl > K2SO4. At 350 °C, the NOxconversion of the K2SO4poisoning catalyst (0.5 wt % K) was 53%, while that of the K2O and KCl poisoning catalysts was only 2 and 4%, respectively. The atomic ratio of V5+/V4+(0.76) and the proportion of adsorbed oxygen species (48%) on the surface of the K2SO4poisoning sample were higher than those of the K2O poisoning sample (0.64, 36%) and the KCl poisoning sample (0.66, 36%). The above phenomena were due to the different poisoning mechanisms caused by K2O, KCl, and K2SO4. K2O decreased the number of Brønsted and Lewis acid sites and, moreover, reduced V5+to V4+; K in KCl preferred to occupy Brønsted acid sites and Cl in KCl reduced Lewis acid sites. SO42–in K2SO4counteracted the impact of K on the surface acid sites and V5+of the poisoned catalyst and generated new Brønsted acid sites. |
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