Jabłońska Magdalena, Mollá Robles Alejandro, Rotko Marek, Vuong Thanh Huyen, Lei Huarong, Lavrič Žan, Grilc Miha, Lukman Muhammad Fernadi, Valiullin Rustem, Bertmer Marko, Möllmer Jens, Rabeah Jabor, Pöppl Andreas, Simon Ulrich, Gläser Roger
Institute of Chemical Technology, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany.
Department of Chemical Technology, Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland.
ChemSusChem. 2024 Nov 11;17(21):e202400198. doi: 10.1002/cssc.202400198. Epub 2024 Sep 24.
Commercial SSZ-13 zeolite with different n(Si)/n(Al) ratios and from different suppliers were subjected to a post-synthetic treatment in order to create mesopores of up to 15 nm. Furthermore, the materials were modified with copper ions and thoroughly physico-chemically characterized. The modified textural properties varied the nature of copper species, and thus, activity in the selective catalytic reduction of NO with ammonia (NH-SCR-DeNO). Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) studies with hexane as probe liquid revealed improved intracrystalline diffusion for some Cu-containing SSZ-13 materials. The NH-SCR-DeNO pathways are verified via in situ DR UV-Vis, in situ FT-IR and EPR, temperature-programmed studies as well as SSITKA studies that provide a mechanistic understanding of the reaction. Kinetic modelling results demonstrate the highest NH-SCR-DeNO reaction rates and up to 20 % lower energy barriers with n(Si)/n(Al) ratio of 6.5 for all modified forms (i. e., (NH)Cu-SSZ-13_6.5 and Cu-SSZ-13_6.5_NaOH/0.1) and cause only negligible parasitic ammonia oxidation. The modelling of the stop-flow experiments further demonstrates that the SCR pathway via the HONO surface intermediate is present but barely contributes to the overall NO conversion compared to the dominant path between adsorbed NH and NO from the gas phase.
对来自不同供应商、具有不同硅铝比（n(Si)/n(Al)）的商用SSZ-13沸石进行了后合成处理，以形成孔径达15 nm的中孔。此外，还用铜离子对这些材料进行了改性，并对其进行了全面的物理化学表征。改性后的织构性质改变了铜物种的性质，进而影响了氨选择性催化还原NO（NH-SCR-DeNO）的活性。以己烷为探针液体的脉冲场梯度核磁共振（PFG-NMR）研究表明，某些含铜的SSZ-13材料的晶内扩散得到了改善。通过原位漫反射紫外可见光谱、原位傅里叶变换红外光谱和电子顺磁共振、程序升温研究以及稳态同位素瞬变动力学分析（SSITKA）研究验证了NH-SCR-DeNO途径，这些研究提供了对该反应的机理理解。动力学建模结果表明，对于所有改性形式（即(NH)Cu-SSZ-13_6.5和Cu-SSZ-13_6.5_NaOH/0.1），当硅铝比为6.5时，NH-SCR-DeNO反应速率最高，能垒降低高达20%，且仅导致可忽略不计的寄生氨氧化。停流实验的建模进一步表明，经由HONO表面中间体的SCR途径存在，但与气相中吸附的NH和NO之间的主导路径相比，对整体NO转化率的贡献很小。
