Deactivation Mechanism of Potassium on the γ-Fe2O3 Catalysts for SCR Reaction: A DFT Study

IF 2.3 4区化学 Q3 CHEMISTRY, PHYSICAL Catalysis Letters Pub Date : 2024-09-22 DOI:10.1007/s10562-024-04825-5

Jin-Qin Zhong, Zi-Peng Li, Dong-Dong Ren, Jian-Xiang Guo, Ji-Jin Wang, Lin-Yang Zhang, Na Liu

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Abstract

The presence of alkali metals in flue gas can lead to catalyst poisoning, which can significantly impact the de-NOx efficiency of the catalyst. There is a lack of specific studies on the influence of potassium (K) poisoning on the efficiency of γ-Fe₂O₃. In this study, the mechanism of K poisoning on the γ-Fe₂O₃ surface was studied based on DFT, and the influence of K on molecular adsorption and SCR reaction process was analyzed. The results show that the K₂O and KCl provide O, K, and Cl ions when deposited on the catalyst surface. The adsorption and dehydrogenation processes of NH3 were enhanced to varying degrees near the O and Cl iron sites, but the subsequent generation and decomposition of NH₂NO were inhibited. On the sites near K cations, the adsorption, dehydrogenation, and subsequent SCR reaction processes of NH₃ are hindered, and the adverse effects on the reaction are greater on the Fe sites closer to K. As well as the presence of K can to some extent promote the adsorption of NO and O₂.

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钾在用于 SCR 反应的 γ-Fe2O3 催化剂上的失活机理：DFT 研究

烟气中碱金属的存在会导致催化剂中毒，从而严重影响催化剂的脱氮效率。目前还缺乏关于钾（K）中毒对 γ-Fe2O3 效率影响的具体研究。本研究基于 DFT 研究了 K 在 γ-Fe2O3 表面中毒的机理，分析了 K 对分子吸附和 SCR 反应过程的影响。结果表明，当 K2O 和 KCl 沉积在催化剂表面时，会提供 O、K 和 Cl 离子。在 O 和 Cl 铁位点附近，NH3 的吸附和脱氢过程得到不同程度的增强，但随后 NH2NO 的生成和分解受到抑制。在靠近 K 阳离子的位点上，NH3 的吸附、脱氢和随后的 SCR 反应过程受到阻碍，而在靠近 K 的铁位点上，对反应的不利影响更大。

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来源期刊

Catalysis Letters 化学-物理化学

CiteScore

5.70

自引率

3.60%

发文量

327

审稿时长

1 months

期刊介绍： Catalysis Letters aim is the rapid publication of outstanding and high-impact original research articles in catalysis. The scope of the journal covers a broad range of topics in all fields of both applied and theoretical catalysis, including heterogeneous, homogeneous and biocatalysis. The high-quality original research articles published in Catalysis Letters are subject to rigorous peer review. Accepted papers are published online first and subsequently in print issues. All contributions must include a graphical abstract. Manuscripts should be written in English and the responsibility lies with the authors to ensure that they are grammatically and linguistically correct. Authors for whom English is not the working language are encouraged to consider using a professional language-editing service before submitting their manuscripts.