The utilization of red mud as a solid waste to fabricate high-value-added products was a critical approach to reduce its storage. This research successfully synthesized a series of Cu-based BEA zeolite NH-SCR catalysts with the acid-washing-alkali-fusion pretreated red mud as the Al source. XRF, XRD and N adsorption–desorption characterized the textual information of all samples. The H-TPR, XPS, and UV–Vis DRS characterized the electronic structure of Cu. The highest Cu content was obtained in Cu-BA0.5-H among all samples. The Cu-BA0.5-H processed the excellent low-temperature NO removal performance of ca. 99 % in 200 °C ∼ 300 °C when NH/NO was 1. Finally, the DRIFTS analysis was carried out regarding the NH adsorption, NO + O adsorption, and co-adsorption to evaluate the possible reaction route. It was confirmed that the SCR reduction over Cu-BA0.5-H in SCR reactions followed the E-R mechanism, but different critical intermediate species depended on the reaction temperatures. It was deduced that the acid-washing-alkali-fusion pretreatment made the non-water-soluble components containing Si and Al into soluble components and further affected NO removal performance of the fabricated catalysts. Our research provided a novel approach for converting red mud into high-value products and unravelled the possible mechanism for NH-SCR.

中文翻译：

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酸洗碱熔预处理赤泥制备NH3-SCR用铜基BEA沸石

利用赤泥作为固体废物来制造高附加值产品是减少其储存的关键方法。本研究以酸洗碱熔预处理赤泥为铝源，成功合成了一系列铜基BEA沸石NH-SCR催化剂。 XRF、XRD 和 N 吸脱附表征了所有样品的文本信息。 H-TPR、XPS 和 UV-Vis DRS 表征了 Cu 的电子结构。所有样品中 Cu-BA0.5-H 的 Cu 含量最高。 Cu-BA0.5-H 具有优异的低温 NO 去除性能。当 NH/NO 为 1 时，在 200 °C ∼ 300 °C 下为 99 %。最后，对 NH 吸附、NO + O 吸附和共吸附进行 DRIFTS 分析，以评估可能的反应路线。经证实，SCR 反应中 Cu-BA0.5-H 的 SCR 还原遵循 ER 机制，但不同的关键中间体物种取决于反应温度。推测酸洗碱熔预处理使含Si、Al的非水溶性成分转化为可溶性成分，进一步影响了所制备催化剂的NO脱除性能。我们的研究提供了一种将赤泥转化为高价值产品的新方法，并揭示了 NH-SCR 的可能机制。