Sulfur-Mediated Promotion of NH 3 -SCR Activity on CeO 2 Catalysts: An In-Depth Analysis

作者：Qingze Zhang, Zhaoying Wang, Xufeng Mai, Yuanhong Zhong, Ming Sun, Lin Yu · 发表于：Industrial & Engineering Chemistry Research · 年份：2025 · DOI：10.1021/acs.iecr.4c04390 · 被引用次数：10 · 研究领域：Catalytic Processes in Materials Science、Ammonia Synthesis and Nitrogen Reduction、Nanomaterials for catalytic reactions

To elucidate the promotional effect and underlying mechanisms of sulfur doping on the NH 3 -SCR performance of CeO 2 catalysts, a detailed study of sulfated CeO 2 catalysts was conducted. The CeO x S 0.1 catalyst, with modest sulfur doping, outperforms its pure CeO 2 counterpart, achieving over 90% NO x conversion and above 98% N 2 selectivity within the temperature range of 230–480 °C. The enhanced catalytic activity is attributed to the ability of sulfur doping to inhibit the overoxidative dehydrogenation of NH 3, thus improving N 2 selectivity. Sulfation introduces dispersed amorphous sulfate species on the CeO 2 surface, which, despite minimally affecting the catalyst’s crystal structure and surface properties, significantly contribute to the surface acidity by generating S–OH and S═O radicals. These radicals enhance the catalyst’s reducibility and oxygen storage capacity, both crucial for the NH 3 -SCR reaction. However, increasing sulfur doping content leads to the formation of bulk and quasi-bulk sulfates within CeO 2, reducing their chemical reactivity and negatively impacting NH 3 -SCR activity. NH 3 -TPD and Py-IR analyses reveal that sulfation increases the number of strong acid sites on the surface, introducing new Brønsted acid sites with reactivity comparable to that of Lewis acid sites. Consequently, sulfation is identified as an effective strategy to boost the SCR activity of CeO 2 catalysts, offering a promising approach for the development of more efficient ...