Qi Lei, Sun Zhenguo, Tang Qi, Wang Jin, Huang Taizhong, Sun Chuanzhi, Gao Fei, Tang Changjin, Dong Lin
Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, 250022, PR China.
Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, 250022, PR China.
J Hazard Mater. 2020 Sep 5;396:122459. doi: 10.1016/j.jhazmat.2020.122459. Epub 2020 Mar 3.
A series of copper-modified red mud catalysts (CuO/PRM) with different copper oxide contents were synthesized by wet impregnation method and investigated for selective catalytic reduction of NO by NH (NH-SCR). The catalytic results demonstrated that the red mud catalyst with 7 wt% CuO content exhibited the excellent catalytic performance as well as resistance to water and sulfur poisoning. The red mud support and copper-containing catalysts were characterized by XRF, XRD, N adsorption-desorption, HRTEM, EDS mapping, XPS, H-TPR, NH-TPD and in situ DRIFT. The obtained results revealed that well dispersed copper oxide originating from 1 to 7 wt% CuO contents was more facile for the redox equilibrium of Cu + Fe ↔ Cu + Fe shifting to right to form Cu and surface oxygen species than crystalline CuO generating from high CuO loading (9 wt% CuO), which was beneficial to the enhancement of reducibility and the formation of Lewis acid sites on the catalyst surface. All these factors made significant contributions to the improvement of NH-SCR activities for CuO/PRM catalysts. Moreover, in situ DRIFT analysis combined with DFT calculated results confirmed that the finely dispersed copper species not only enhanced the NH activation but also promoted the NO desorption, which synergistically facilitated the NH-SCR process via the Eley-Rideal mechanism.
采用湿浸渍法合成了一系列不同氧化铜含量的铜改性赤泥催化剂（CuO/PRM），并对其进行了氨选择性催化还原NO（NH₃-SCR）性能研究。催化结果表明，氧化铜含量为7 wt%的赤泥催化剂表现出优异的催化性能以及抗水和抗硫中毒性能。采用XRF、XRD、N₂吸附-脱附、HRTEM、EDS图谱、XPS、H₂-TPR、NH₃-TPD和原位DRIFT对赤泥载体和含铜催化剂进行了表征。结果表明，1至7 wt%氧化铜含量的氧化铜分散良好，比高氧化铜负载量（9 wt% CuO）生成的结晶CuO更有利于Cu²⁺ + Fe³⁺ ↔ Cu⁺ + Fe⁴⁺的氧化还原平衡向右移动，形成Cu⁺和表面氧物种，这有利于提高催化剂的还原性和在催化剂表面形成Lewis酸位点。所有这些因素对提高CuO/PRM催化剂的NH₃-SCR活性都有显著贡献。此外，原位DRIFT分析结合DFT计算结果证实，精细分散的铜物种不仅增强了NH₃的活化，还促进了NO的脱附，通过Eley-Rideal机理协同促进了NH₃-SCR过程。
