Magic Clusters of MoS₂ by Edge S₂ Interdimer Spacing Modulation

Abstract

Edge atomic and electronic structures of S-saturated Mo-edge triangular MoS nanoclusters are investigated using density functional theory calculations. The edge electrons described by the S-p pπ* (S-Π ) and Mo-d orbitals are found to interplay to pin the S-Π Fermi wavenumber at k = 2/5 as the nanocluster size increases, and correspondingly, the ×5 Peierls edge S interdimer spacing modulation is induced. For the particular sizes of N = 5 n - 2 and 5 n, where N is the number of Mo atoms at one edge representing the nanocluster size and n is a positive integer, the effective ×5 interdimer spacing modulation stabilizes the nanoclusters, which are identified here to be the magic S-saturated Mo-edge triangular MoS nanoclusters. With the S-Π Peierls gap, the MoS nanoclusters become far-edge S-Π semiconducting and subedge Mo-d metallic as N → ∞.

Density Functional Theory Study of Edge-Induced Atomic-Scale Structural Phase Transitions of MoS2 Nanocrystals: Implications for a High-Performance Catalyst

“…The DFT optimized structure of the 2H Mo-edge nanocrystal of size n = 6 and with 100% S coverage is shown in panel 1 of Figure . This edge structure agrees well with previous experimental reports, and theoretical studies using a method such as global optimization. − In the case of the Mo-edge nanocrystals, we also checked that CO molecules could easily form bonds with S atoms at the edges than at the basal plane to form V S . After the S atoms at the edges desorbed, the remaining edge S atoms could migrate in the direction of the red arrows shown in panel 2 of Figure .…”

“…First, we compared the stability of 2H S-edge MoS 2 triangular nanocrystals ( n = 6, 100% S coverage) with various edge S-dimer configurations. There are several theoretical studies on the edge S structures of the 2H MoS 2 nanoribbons or triangular nanocrystals. − In these studies, it was mentioned that the S-edge with 100% S coverage is stable and S dimerization is the key factor in stabilizing the structure of MoS 2 . However, there was no detailed study on the number and the position of S dimerization occurring at the edge of the 2H S-edge MoS 2 nanocrystals.…”

Nanoclusters for photoelectrochemical water splitting: Bridging the photosensitizer and carrier transporter

“…Metal chalcogenide clusters (MCCs), such as zinc sulfide, cadmium sulfide, cadmium selenide, and molybdenum sulfide, are made of relatively small number of atoms, with sizes smaller than 3 nm, named as magic-size clusters (MSCs). [149][150][151][152][153] MSCs were first discovered in the II-VI nanoparticle research in 1984. 150 Thereafter, the spectral features of MSCs were frequently observed in the early stages of nanocrystal synthesis with every MSC having mainly a single sharp absorption peak.…”

“…Metal chalcogenide clusters (MCCs), such as zinc sulfide, cadmium sulfide, cadmium selenide, and molybdenum sulfide, are made of relatively small number of atoms, with sizes smaller than 3 nm, named as magic‐size clusters (MSCs) 149–153 . MSCs were first discovered in the II‐VI nanoparticle research in 1984 150 .…”