Spongy chalcogels of non-platinum metals act as effective hydrodesulfurization catalysts

Abstract

Aerogels are low-density porous materials, made mostly of air, for which hundreds of applications have been found in recent years. Inorganic oxide-based aerogels have been known for a long time, carbon aerogels were discovered in the early 1990s and sulfur- and selenium-based aerogels (chalcogels) are the most recent additions to this family. Here we present new aerogels made of Co(Ni)–Mo(W)–S networks with extremely large surface areas and porosity. These systems are formed by the coordinative reactions of (MoS₄)²⁻ and (WS₄)²⁻ with Co²⁺ and Ni²⁺ salts in non-aqueous solvents. We show that these low-density sponge-like networks can absorb conjugated organic molecules and mercury ions, and preferentially adsorb CO₂ over H₂, which illustrates their high potential as gas-separation media. The chalcogels are shown to be twice as active as the conventional sulfided Co–Mo/Al₂O₃ catalyst for the hydrodesulfurization of thiophene.