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Co n -1 TMO n -2 + ( n = 6-8), (TM = V, Cr, Mn, and Fe) clusters are investigated using density functional theory calculations. The transition metal atoms preferentially replace one Co atom at sites where the number of metal-oxygen bonds is maximized, forming more stable structures. The evaporation of a Co atom is the most fragile dissociation channel for both pure and doped species. Bare cobalt oxide clusters exhibit parallel spin ordering, whereas both parallel and antiparallel spin ordering are observed in the doped species. Notably, a ferromagnetic-to-ferrimagnetic transition occurs in the V-doped clusters, while the ferromagnetic behavior is enhanced in the Fe-doped species., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

Molecular and dissociative hydrogen adsorption of transition metal (TM)-doped [Mo 3 S 13 ] 2- atomic clusters were investigated using density functional theory calculations. The introduced TM dopants form stable bonds with S atoms, preserving the geometric structure. The S-TM-S bridging bond emerges as the most stable configuration. The preferred adsorption sites were found to be influenced by various factors, such as the relative electronegativity, coordination number, and charge of the TM atom. Notably, the presence of these TM atoms remarkably improved the hydrogen adsorption activity. The dissociation of a single hydrogen molecule on TM[Mo 3 S 13 ] 2- clusters (TM = Sc, Cr, Mn, Fe, Co, and Ni) is thermodynamically and kinetically favorable compared to their bare counterparts. The extent of favorability monotonically depends on the TM impurity, with a maximum activation barrier energy ranging from 0.62 to 1.58 eV, lower than that of the bare cluster (1.69 eV). Findings provide insights for experimental research on hydrogen adsorption using TM-doped molybdenum sulfide nanoclusters, with potential applications in the field of hydrogen energy., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Increasing interest has been paid for hydrogen adsorption on atomically controlled nanoalloys due to their potential applications in catalytic processes and energy storage. In this work, we investigate the interaction of H 2 with small-sized Ag n Cr ( n = 1-12) using density functional theory calculations. It is found that the cluster structures are preserved during the adsorption of H 2 either molecularly or dissociatively. Ag 3 Cr-H 2 , Ag 6 Cr-H 2 , and Ag 9 Cr-H 2 clusters are identified to be relatively more stable from computed binding energies and second-order energy difference. The dissociation of adsorbed H 2 on Ag 2 Cr, Ag 3 Cr, Ag 6 Cr, and Ag 7 Cr clusters is favored both thermodynamically and kinetically. The dissociative adsorption is unlikely to occur because of a considerable energy barrier before reaching the final state for Ag 4 Cr or due to energetic preferences for n = 1, 5, and 8-12 species. Comprehensive analysis shows that the geometric structure of clusters, the relative electronegativity, and the coordination number of the Cr impurity play a decisive role in determining the preferred adsorption configuration., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

A theoretical study of geometric and electronic structures, stability and magnetic properties of both neutral and anionic Ge 16 M 0/- clusters with M being a first-row 3d transition metal atom, is performed using quantum chemical approaches. Both the isoelectronic Ge 16 Sc - anion and neutral Ge 16 Ti that have a perfect Frank-Kasper tetrahedral T d shape and an electron shell filled with 68 valence electrons, emerge as magic clusters with an enhanced thermodynamic stability. The latter can be rationalized by the simple Jellium model. Geometric distortions from the Frank-Kasper tetrahedron of Ge 16 M having more or less than 68 valence electrons can be understood by a Jahn-Teller effect. Remarkably, DFT calculations reveal that both neutral Ge 16 Sc and Ge 16 Cu can be considered as superhalogens as their electron affinities (≥3.6 eV) exceed the value of the halogen atoms and even that of icosahedral Al 13 . A detailed view of the magnetic behavior of Ge 16 M 0/- clusters shows that the magnetic moments of the atomic metals remain large even when they are quenched upon doping. When M goes from Sc to Zn, the total spin magnetic moment of Ge 16 M 0/- increases steadily and reaches the maximum value of 3 μ B with M = Mn before decreasing towards the end of the first-row 3d block metals. Furthermore, the IR spectra of some tetrahedral Ge 16 M are also predicted., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)