Global optimization of ~ 1 nm MoS 2 and CaCO 3 nanoparticles

The study of materials in the nanoscale regime has important applications for catalytic reactions, the energy industry and medicine. We performed exploratory density functional theory calculations for molybdenum disulphide (MoS 2 ) and calcium carbonate (CaCO 3 ) nanoparticles (NPs), the former being developed as a hydrogenation and coke-prevention catalyst and the latter representing the catalytic support in some reservoirs. Utilizing Born–Oppenheimer Molecular Dynamics with reduced masses as a global optimization method, we found Mo 8 S 16 and Mo 16 S 32 NPs with lower-lying energies than those of locally optimized crystal geometries. Our results suggest that MoS 2 NPs prefer a tetragonal lattice arrangement which is in agreement with previous studies of smaller MoS 2 NPs. It remains to be seen how prenucleation MoS 2 clusters of the hexagonal phase are formed. The CaCO 3 NPs showed small energy differences between vastly different conformations. Therefore, in order to capture only their supporting effects in reservoirs, one should consider keeping a substantial part of the models fixed.