催化作用
氧化铌
化学
脱氢
氧化物
无机化学
吸附
锆
氨
布朗斯特德-洛瑞酸碱理论
无定形固体
活化能
路易斯酸
物理化学
结晶学
有机化学
作者
Linna Li,Xuan He,Da‐Ming Zhu,Huimin Wang,Jiashang Chen,Qiulin Zhang,Ping Ning
出处
期刊:ACS Sustainable Chemistry & Engineering
[American Chemical Society]
日期:2023-11-22
卷期号:11 (48): 17015-17030
标识
DOI:10.1021/acssuschemeng.3c04971
摘要
NH3 elimination is highly desired during hazy pollution periods. However, the enhanced low-temperature activity and in-depth understanding of the reaction mechanism remain a tough challenge for NH3 selective catalytic oxidation (NH3–SCO) to N2. Here, a zirconium–niobium composite oxide-supported 0.2 wt % RuOx component (R/Z-N) was synthesized and systematically investigated. Compared with its counterparts (RuOx/ZrO2 and RuOx/Nb2O5), R/Z-N presented superior NH3 removal performance, obtaining complete conversion of NH3 at 300 °C and 90% N2 selectivity at a wide temperature window of 175–300 °C, followed by a lower apparent activation energy (79.2 kJ/mol). Thorough structural and surface property analysis revealed that the unique amorphous Nb2Zr6O17 structure was formed over R/Z-N through strong zirconia–niobium oxide interaction, resulting in its highest fraction of medium strong acid, surface adsorbed oxygen, and RuO2 catalytic active sites among these samples. Detailed situ DRIFTS studies further revealed that NH4+ species adsorption on Bro̷nsted acid sites exhibited higher activity compared to NH3 on Lewis. Thus, the plentiful Bro̷nsted acid sites over R/Z-N could accelerate the activation and dehydrogenation of NH3, further promoting the fast NH3–SCO process via the i-SCR mechanism, thereby improving activity. This work could guide the development of a high-efficiency catalyst for NH3 purification via tuning acidic active species.
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