The organization of aluminium atoms in zeolites affects their catalytic properties. Here we demonstrate that the aluminium distribution is a key parameter controlling the reaction pathway of acid catalysed reactions over ZSM-5 zeolites. We study ethanol transformation over two ZSM-5 samples with similar Si/Al ratios of ~15, and with aluminium atoms located mainly at the channel intersections but differently distributed in the framework. One of the samples contains mostly isolated aluminium atoms while the other has a large fraction of two aluminium atoms located in one ring. The FT-IR time-resolved operando study, supported by catalytic results, reveals that the reaction pathway in ethanol transformation over ZSM-5 is controlled by the proximity of aluminium atoms in the framework. ZSM-5 containing mostly isolated Al atoms transforms ethanol in the associative pathway, and conversely ZSM-5 containing a dominating fraction of two aluminium atoms in one ring transforms ethanol in the dissociative pathway.

沸石中铝原子的组织影响其催化性能。在这里，我们证明铝分布是控制 ZSM-5 沸石上酸催化反应的反应途径的关键参数。我们研究了两个 ZSM-5 样品的乙醇转化，这些样品具有相似的 Si/Al 比，约为 15，铝原子主要位于通道交叉点，但在框架中分布不同。其中一个样品主要包含孤立的铝原子，而另一个样品中有大部分位于一个环中的两个铝原子。由催化结果支持的 FT-IR 时间分辨操作数研究表明，ZSM-5 上乙醇转化的反应途径受框架中铝原子的接近度控制。