An active and stable catalyst of Zn modified Pt nanoparticles encapsulated within silicalite-1 zeolite for dehydrogenation of ethane

Abstract

The rapid deactivation of catalysts for ethane dehydrogenation (EDH) at considerably higher temperature and the relatively inert feature of ethane makes it urgent to develop highly active and stable catalysts. Herein, a Zn modified Pt nanoparticles confined within silicalite-1 (S-1) zeolite catalyst for EDH reaction was synthesized by hydrothermal synthesis using the PtZn/SiO2 precursor without any protective ligands, which achieved extremely high catalytic performance (e.g., 15.9 % conversion which was close to the thermodynamic equilibrium limitation, 99.5 % ethylene selectivity, and 0.001 h−1 the deactivation rate). Multiple characterizations with XPS, in situ CO-DRIFTS, in situ C2H6-DRIFTS, TG-DTA, and Raman techniques on these catalysts revealed that the electron-rich Pt sites with stable electronic environment formed by Zn promoter introduced, resulting in enhanced anti-reduction and coke-resistance abilities. Furthermore, characterizations with XRD, HRTEM, Py-IR, hydroxyl vibration region of DRIFT spectra and 1H MAS NMR spectroscopic analysis showed that the dilution effect of Zn and the trapping of zinc and platinum species by Si-OH groups in the form of (≡Si-O-Zn)xPt complex could inhibit migration and aggregation, resulting in smaller metal particles and increase anti-sintering ability. The superior catalytic performance as well as the environmental benign preparation route with no-ligand will further contribute to the advantages for future applications.