Solution synthesis of core–shell Co9S8@MoS2 catalysts

Abstract

Core–shell Co₉S₈@MoS₂ unsupported catalysts have been prepared by a solution reaction in ethylene glycol. First, using a cobalt sulfide seed, amorphous core–shell CoS@MoS_x (x = 3–4) was prepared. Then, after thermal treatment, 20–50 nm-sized particles were obtained, in which MoS₂ was crystallized at the exterior of the Co₉S₈ core. The solids show high catalytic activity in hydrodesulphurization, with an exceptionally high thermal stability. Thus, the high catalytic activity was preserved even after thermal treatment at 750 °C. A symmetric synergy model has been proposed with the catalytic sites located at the interface between the cobalt sulfide crystallites and the stacks of MoS₂ slabs.