Nuguid Rob Jeremiah G, Ortino-Ghini Lorenzo, Suskevich Vitaly L, Yang Jie, Lietti Luca, Kröcher Oliver, Ferri Davide
Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
Institute of Chemical Sciences and Engineering, École polytechnique fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Phys Chem Chem Phys. 2022 Feb 16;24(7):4555-4561. doi: 10.1039/d1cp05261f.
Lewis acid sites (LAS) and Brønsted-Lowry acid sites (BAS) play key roles in many catalytic processes, particularly in the selective catalytic reduction (SCR) of nitrogen oxides with ammonia. Here we show that temperature, gas feed, and catalyst composition affect the interplay between LAS and BAS on vanadia-based materials under SCR-relevant conditions. While different LAS typically manifest as a single collective peak in the steady-state spectra, their individual signals could be isolated through the increased sensitivity of transient experimentation. Furthermore, water could increase BAS not just by converting pre-existing LAS, but also by generating spontaneously new acid sites. These results pave the way for understanding the relationship between LAS and BAS, and how their ratio determines the reactivity of vanadia-based catalysts not just in SCR but in other chemical transformations as well.
路易斯酸位点（LAS）和布朗斯特-劳里酸位点（BAS）在许多催化过程中起着关键作用，特别是在氨选择性催化还原（SCR）氮氧化物的过程中。在这里，我们表明，在与SCR相关的条件下，温度、气体进料和催化剂组成会影响钒基材料上LAS和BAS之间的相互作用。虽然不同的LAS通常在稳态光谱中表现为一个单一的集体峰，但通过瞬态实验提高的灵敏度可以分离出它们各自的信号。此外，水不仅可以通过转化预先存在的LAS来增加BAS，还可以自发地产生新的酸位点。这些结果为理解LAS和BAS之间的关系以及它们的比例如何不仅在SCR中而且在其他化学转化中决定钒基催化剂的反应性铺平了道路。
