Small-Molecule Modification Provides Pt Nucleation Sites for Enhanced Propane Dehydrogenation Performance

The rational synthesis of catalysts with controllable structures and the study of their structure-activity relationships to break the limitations of traditional catalysts remain challenging. Herein, tetrakis(dimethylamido)tin (TDMASn) exposures were used to modify silicalite-1 (S-1) lacking suitable chemisorption sites on their surfaces to provide Pt nucleation sites, obtaining a Pt/20TDMASn/S-1 sample. For comparison, Pt species supported on bare S-1 (Pt/S-1) and Pt species supported on the S-1 of pre-deposited SnO₂ (Pt/20SnO₂/S-1) were also prepared. Catalysts were characterized extensively by X-ray diffraction, temperature-programmed reduction, transmission electron microscopy, X-ray photoelectron spectroscopy, and diffuse-reflectance infrared Fourier transform spectroscopy of adsorbed CO. The results showed that this surface modification (TDMASn or SnO₂) yielded up to about a 40-times increase in Pt content after 20 cycles of Pt atomic layer deposition (ALD). Compared with Pt/20SnO₂/S-1, Pt/20TDMASn/S-1 had a smaller particle size, stronger interactions between the metal species and the support, and a lower Sn⁰ content, thus resulting in a remarkably higher initial propane conversion in the propane dehydrogenation (PDH) reaction. The catalytic activity could also be optimized based on the number of ALD-TDMASn exposures. As a consequence, Sn not only provided nucleation sites for Pt but also acted as a promoter to enhance the catalyst performance. This fundamental understanding will help researchers obtain suitable catalysts for PDH processes.