From core–shell MoSx/ZnS to open fullerene-like MoS2 nanoparticles

Abstract

A new two-step solution route has been developed for the preparation of hollow inorganic fullerene-like (IF) MoS₂ particles with a quantitative yield. First, core–shell MoS_x/ZnS (x ∼ 3–4) particles were synthesized by depositing amorphous MoS_x on the ZnS seeds in a solution containing ethylene glycol and elemental sulfur. Core–shell particles contain a 7–9 nm size ZnS core surrounded with an amorphous MoS_x sulfide shell. Then the core–shell particles were thermally treated at 400–750 °C. As a result, 20–50 nm size IF-like MoS₂ particles were crystallized, whereas ZnS left the interior of the particles and formed bulky crystals aside. At the moment of ZnS crystallization a burst-out of the MoS₂ walls occurs and the resulting IF particles contain openings, which make the internal voids accessible for gas adsorption. By means of varying the Mo/Zn ratio in the solvothermal reaction mixture, the number of slabs in the onion-like particles can be controlled. Due to the intermediate presence of the ZnS core, relatively large voids are created in the resulting IF-MoS₂. The solids as obtained possess high specific surface area, enhanced thiophene HDS activity and exceptional thermal stability. Particle size and wall thickness can be controlled by means of variation of the Mo/Zn atomic ratio in the solution.