A DFT study and experimental evidence of the sonication-induced cleavage of molybdenum sulfide Mo2S3 in liquids

The Mo-S phase diagram exhibits two stable compounds: well-recognized layered molybdenum disulfide MoS2 and less studied molybdenum sesquisulfide Mo2S3. Here, we build a theoretical framework for the exfoliation of Mo2S3 based on density functional theory calculations and further experimentally prove its dispersibility under ultrasonic treatment and demonstrate its potential for use in gas detectors. First, we report computational studies of both Mo2S3 exfoliation and molecular adsorption on the Mo2S3 surface. The calculations reveal the preferential direction for the fragmentation of the Mo2S3 crystal along the (101) plane and, likely, chemisorptive interaction of solvent molecules, such as H2O or DMSO, with the (101) Mo2S3 surface. Next, we experimentally study the sonication of bulk Mo2S3 samples in organic solvents and show that, indeed, they may be converted to colloidal nanosized sheets. Solid particles in the dispersions retain the initial Mo2S3 crystal structure and have the shape of plates with typical thicknesses of 5-30 nm and lateral sizes of 100-400 nm. Finally, we investigate the gas sensing properties of the Mo2S3 films deposited from the dispersions towards moisture gas and several representative volatile organic compounds.