Transition metal atoms encapsulated within microporous Silicalite-1 zeolite: A systematic computational study

Abstract

Single-atom catalysts (SACs) have emerged as a novel class of catalysts that show unique catalytic properties thanks to their easy tuneability. In this context, zeolites are widely used as support materials for SACs, since the steric restrictions from their channels can effectively suppress the aggregation of the metal particles and provide encapsulated metal atoms with exceptional stability. Although significant efforts have been made to study zeolite-supported SACs, only a few transition metal atoms have been tested, and the determination of precise locations of single metal atoms within the zeolite matrix by experiments remains a nontrivial task. Herein we provide a thorough dispersion corrected density functional theory study of the energetic, structural, magnetic and electronic properties for the full sets of 3d, 4d and 5d transition metal atoms encapsulated on MFI-type Silicalite-1 zeolite, namely TM@S-1. Most TM atoms prefer to adsorb in the center of the S-1 channels, weakly interacting with the zeolite, with the exception of Group 3 − Sc, Y, La − , Group 10 − Ni, Pd, Pt − , Ru and Rh atoms, making them good candidates as stable SACs with superior catalytic performance. The optimized geometry files for the full set of TM@S-1 have been uploaded to a public online repository, paving the road for further catalytic studies of these systems. The behavioral trends gained from this study provide a solid theoretical background that can be used as the basis for interpreting, understanding, and discussing already observed experimental features, and future findings as well. • Only 4 specific sites in S-1 are preferred by the entire set of TM adatoms. • TM@S-1 of groups 3, 10, 11 & 12 more resistant against sintering than other groups. • Weakest Eads for group 11 and 12 TMs with a full occupancy of d orbitals. • Similar behavior for TMs of groups 6 and 7 with half occupancy of orbitals. • All TMs n-dope S-1, except Pt, which p-dopes it.