Probing the Smallest Molecular Model of MoS₂ Catalyst: S₂ Units in the MoS_n^–/0 (n = 1–5) Clusters

Abstract

Density functional theory (DFT) and coupled cluster theory (CCSD(T)) calculations are carried out to investigate the electronic and structural properties of a series of monomolybdenum sulfide clusters, MoSn(-/0) (n = 1-5). Generalized Koopmans' theorem is applied to predict the vertical detachment energies and simulate the photoelectron spectra (PES). We found that the additional sulfur atoms have a tendency to successively occupy the terminal sites in the sequential sulfidation until the Mo reaches its maximum oxidation sate of +6. After that, the polysulfide ligands (viz., S2 and S3) emerge in the MoS4 and MoS5(-/0) clusters. The MoS4 (C2, (1)A) is predicted to be the ground state and may be used as a neutral model for the sulfur-rich edge sites of the fresh MoS2 catalysts. Molecular orbital analyses are performed to analyze the chemical bonding in the monomolybdenum sulfide clusters and to elucidate their electronic and structural evolution.

Structural Properties of Gas Phase Molybdenum Sulfide Clusters [Mo3S13]2–, [HMo3S13]−, and [H3Mo3S13]+ as Model Systems of a Promising Hydrogen Evolution Catalyst

“…In particular, partial exchange of terminal disulfides (S 2 2– ) with aqua ligands leads to [Mo 3 S (13‑ x ) (H 2 O) x ] ( x ‑2)+ ( x = 2, 4) which could be identified as the most active catalytic species in solution . Small charged and neutral molybdenum sulfide clusters have also been studied both experimentally − and theoretically − to understand their catalytic properties. Further insight can also be gained by investigating the surface chemistry of molybdenum sulfide and chemically similar systems, e.g., molybdenum oxides − or molybdenum-doped clusters. − A series of [MoO­(S 2 ) 2 L 2 ] complexes have been developed by Wu and co-workers as tunable molecular MoS 2 edge-site mimics for electrocatalytic hydrogen production. − …”

Non‐Dissociative Activation of Chemisorbed Dinitrogen on One or Two Vanadium Atoms Supported by a Mo6S8 Cluster

“…DFT calculations were performed using Gaussian 09 program [34] with the hybrid B3LYP functional [35] (with 20 % Hartree‐Fock exchange). This functional was chosen since it has been widely adopted in previous studies on molybdenum sulfide clusters and provided reasonable results [20a–e] (more discussion on the choice of B3LYP is in the ESI, including the comparison with M06 [36] ). Grimme's dispersion corrections (D3BJ) were included to describe the interactions between atoms more accurately [37] .…”

Amorphous nickel/cobalt tungsten sulfide electrocatalysts for high-efficiency hydrogen evolution reaction

“…Theoretical and experimental studies have revealed that molybdenum sulfide and tungsten sulfide with various coordination states such as MoS 2 edge, MoS 4 2− , Mo 3 S 4 4+ , and Mo 3 S 13 2− exhibit different G H and catalytic ability [68][69][70][71]. Ni and Co are widely applied to MS 2 -derived HER or HDS catalysts because of the enhancement effect rendered by the edge structures [5,46].…”