| Autor: |
Li G; School of Resources and Environment, Nanchang University, Nanchang, Jiangxi 330031, PR China., Li G; College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, PR China., Liao M; College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, PR China., Liu W; College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, PR China., Zhang H; School of Resources and Environment, Nanchang University, Nanchang, Jiangxi 330031, PR China., Huang S; School of Resources and Environment, Nanchang University, Nanchang, Jiangxi 330031, PR China., Huang T; School of Resources and Environment, Nanchang University, Nanchang, Jiangxi 330031, PR China., Zhang S; School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China., Li Z; National Engineering Laboratory for Mobile Source Emission Control Technology, China Automotive Technology & Research Center, Tianjin 300300, PR China., Peng H; School of Resources and Environment, Nanchang University, Nanchang, Jiangxi 330031, PR China.; College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, PR China. |
| Abstrakt: |
Selective catalytic reduction of nitrogen oxides (NO x ) with ammonia (NH 3 -SCR) is an efficient NO x reduction strategy, while the denitrification ( de NO x ) catalysts suffer from serious deactivation due to the coexistence of multiple poisoning substances, such as alkali metal (e.g., K), SO 2 , etc ., in industrial flue gases. It is essential to understand the interaction among various poisons and their effects on the de NO x process. Herein, the ZSM-5 zeolite-confined MnSmO x mixed (MnSmO x @ZSM-5) catalyst exhibited better de NO x performance after the poisoning of K, SO 2 , and/or K&SO 2 than the MnSmO x and MnSmO x /ZSM-5 catalysts, the de NO x activity of which at high temperature (H-T) increased significantly (>90% NO x conversion in the range of 220-480 °C). It has been demonstrated that K would occupy both redox and acidic sites, which severely reduced the reactivity of MnSmO x /ZSM-5 catalysts. The most important, K element is preferentially deposited at -OH on the surface of ZSM-5 carrier due to the electrostatic attraction (-O-K). As for the K&SO 2 poisoning catalyst, SO 2 preferred to be combined with the surface-deposited K (-O-K-SO 2ads ) according to XPS and density functional theory (DFT) results, the poisoned active sites by K would be released. The K migration behavior was induced by SO 2 over K-poisoned MnSmO x @ZSM-5 catalysts, and the balance of surface redox and acidic site was regulated, like a synergistic promoter, which led to K-poisoning buffering and activity recovery. This work contributes to the understanding of the self-detoxification interaction between alkali metals (e.g., K) and SO 2 on de NO x catalysts and provides a novel strategy for the adaptive use of one poisoning substance to counter another for practical NO x reduction. |
