Stabilizing Pd Catalysts for Liquid-Phase Hydrogenation of N‑Heterocyclic Hydrogen Carriers through Zeolite
Sara Ahsan1, Sirinada Chanthachaiwat1, Alexander Kvit2
1Department of Chemical and Biological Engineering, University of Wisconsin- Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States.
Abstract:
N-Heterocyclic aromatics can reversibly store H2 through (de)-hydrogenation over supported Pd catalysts, but metal nanoparticles often sinter during liquid-phase reactions. Here, we report that the encapsulation of Pd nanoparticles in large-pore zeolites stabilizes Pd catalysts during hydrogenation of N-methylindole (N-MID). Flow reactor studies combined with post-reaction characterizations show that Pd nanoparticles supported on SiO2 or Al2O3 sinter during hydrogenation of N-MID, while Pd/zeolites (particularly Pd/Beta) retain <2 nm particles, likely by suppressing the chelation and migration of Pd by N-MID. This work highlights the potential of zeolitic voids to suppress metal catalyst deactivation in liquid-phase reactions including H2 storage in chemical bonds.
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