Boosting Propane Dehydrogenation over PtZn Encapsulated in an Epitaxial High-Crystallized Zeolite with a Low Surface Barrier

Abstract

Metal clusters encapsulated in zeolites have attracted increasing attention because of their unique electronic properties with high stability, but diffusion limitation is the bottleneck in the utilization efficiency of active sites, especially in bulk crystals. Nanosized zeolites could effectively improve mass transport by shortening the diffusion length. However, their rough surface and low crystallinity lead to a high surface barrier and low stabilization effect, respectively. Here, we developed a dual-template method to synthesize finned MFI zeolites to encapsulate PtZn clusters. In a propane dehydrogenation reaction, the as-prepared PtZn@S-1-Fin exhibited a high specific activity of 17.0 molC3H6 molPt–1 s–1 at 600 °C, which was about 1.7 times higher than that of PtZn confined in a nanosized zeolite. This could be attributed to the epitaxial highly crystallized zeolite combining a short diffusion length and a high surface permeability simultaneously.