State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China.
State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China.
J Hazard Mater. 2021 Feb 15;404(Pt A):123936. doi: 10.1016/j.jhazmat.2020.123936. Epub 2020 Sep 14.
In this paper, the simultaneous removal of SO and NO catalyzed by Fe-Mo mixed oxides at varying Mo/Fe atomic ratios was reported for the first time with the aim of reducing HO consumption and elucidating the roles of Fe and Mo species in the catalytic process. Fe-Mo mixed oxides with varying Mo/Fe atomic ratios were synthesized and the catalytic performances were systematically studied. The catalyst with Mo/Fe atomic ratio of 2.0 exhibited the highest activity, with which removal efficiencies of 89.4 % for NO and 100 % for SO can be attained at extremely low HO dosage. Products analysis revealed that SO was mainly removed via wet scrubber, while the adequate oxidation resulting from OH radicals was the prerequisite for NO removal. The redox pair of Fe/Fe played a significant role in decomposing HO, while Mo species had double effect on catalytic activity. Higher Mo content resulted in abundant oxygen vacancies and stronger surface acidity, which favored OH formation. However, the excessive Mo content involved severe surface Mo enrichment and remarkably reduced the active sites of Fe species. The HO/Fe-Mo catalyst system showed excellent stability and had a promising prospect for simultaneously removing SO and NO in coal-fired flue gas.
本文首次报道了在不同 Mo/Fe 原子比下，Fe-Mo 混合氧化物同时催化 SO 和 NO 的去除，目的是减少 HO 的消耗，并阐明 Fe 和 Mo 物种在催化过程中的作用。合成了具有不同 Mo/Fe 原子比的 Fe-Mo 混合氧化物，并对其催化性能进行了系统研究。Mo/Fe 原子比为 2.0 的催化剂表现出最高的活性，在极低的 HO 用量下，NO 的去除率可达 89.4%，SO 的去除率可达 100%。产物分析表明，SO 主要通过湿式洗涤器去除，而 OH 自由基的充分氧化是去除 NO 的前提。Fe/Fe 的氧化还原对在分解 HO 中起重要作用，而 Mo 物种对催化活性有双重影响。较高的 Mo 含量导致丰富的氧空位和更强的表面酸度，有利于 OH 的形成。然而，过多的 Mo 含量会导致严重的表面 Mo 富集，从而显著减少 Fe 物种的活性位。HO/Fe-Mo 催化剂体系表现出优异的稳定性，有望用于燃煤烟气中同时去除 SO 和 NO。
