Porous MoS₂ synthesized by ultrasonic spray pyrolysis

The hydrodesulfurization (HDS) activity of molybdenum sulfide-based catalysts is localized to the edges of this layered solid and is, therefore, highly dependent on the technique used to prepare the material. Here, ultrasonic spray pyrolysis (USP) was used to synthesize porous, nanostructured MoS₂. Low surface area powders, not useful for catalysis, are generally produced by USP. This work shows that when combined with a dissolvable template, USP is capable of producing high surface area materials. An aqueous solution of ammonium tetrathiomolybdate and colloidal silica was nebulized and pyrolyzed to give a MoS₂/SiO₂ composite material. Leaching with HF removed the sacrificial SiO₂, resulting in a highly porous MoS₂ network with surface areas as high as 250 m²/g. Cobalt-promoted MoS₂ networks were also synthesized. The thiophene HDS activities of these materials were substantially higher than those of unsupported MoS₂ and RuS₂ standards, illustrating the enhanced dispersion of the HDS active phase achieved by this synthetic technique.