Nanoparticles are of interest in heterogeneous catalysis because of their excellent activity associated with atoms in a low coordination environment. However, their high reactivity becomes a drawback where selectivity is desired, compounded by their propensity towards agglomeration. Here, we show that stable subnanometric Rh particles can be prepared in a Mg-doped zeolite Beta based on the electrostatic interaction of the negatively charged zeolitic framework and the Rh³⁺ precursor. The Mg ions are incorporated into the zeolite framework whereas the Rh is located in the channels adjacent to the Mg. With only 0.27 and 0.5 wt.% Mg and Rh, respectively, the Rh/Mg-Beta catalysts were highly active with > 94 % selectivity for the hydrogenation of phenol to cyclohexanone, an important intermediate for the production of Nylon. Key to the selectivity is the formation of the C=O double bond early in the reaction sequence, aided by the basicity of the Mg-Beta support.

纳米颗粒在非均相催化中很受关注，因为它们在低配位环境中与原子相关的优异活性。然而，在需要选择性的情况下，它们的高反应性成为一个缺点，再加上它们的团聚倾向。在这里，我们表明，基于带负电荷的沸石骨架和 Rh ³⁺的静电相互作用，可以在 Mg 掺杂的沸石 Beta 中制备稳定的亚纳米 Rh 颗粒。前体。Mg 离子结合到沸石骨架中，而 Rh 位于与 Mg 相邻的通道中。分别只有 0.27 和 0.5 重量％的镁和铑，Rh/Mg-Beta 催化剂具有高活性，苯酚氢化成环己酮的选择性 > 94%，环己酮是生产尼龙的重要中间体。选择性的关键是在反应序列的早期形成 C=O 双键，这得益于 Mg-Beta 载体的碱性。