“Non-hydrolytic” sol–gel synthesis of molybdenum sulfides

Abstract

Non-hydrolytic sol–gel reactions provide a low temperature solution based synthetic approach to solid-state materials. In this paper, reactions between molybdenum chloride and hexamethyldisilthiane in chloroform were explored, which gave access to both MoS2 and Mo2S3 after heat treatment of as-recovered amorphous samples to 600–1000°C. Interesting morphologies were obtained for MoS2, ranging from fused spherical particles to well-defined nanoplatelets and nanoflakes. Both 2H- and 3R-MoS2 were observed, which formed thin hexagonal and triangular platelets, respectively. The platelets exhibited thicknesses of 10–30nm, which corresponds to 15–50 MoS2 layers. No attempts to prevent agglomeration were made, however, well separated platelets were observed for many samples. Heating at 1000°C led to formation of Mo2S3 for samples that showed well-defined MoS2 at lower temperatures, while less crystalline samples had a tendency to retain the MoS2 structure.