Exfoliation of bulk 2H-MoS 2 into bilayer 1T-phase nanosheets via ether-induced superlattices

The exfoliation of bulk 2H-molybdenum disulfide (2H-MoS 2 ) into few-layer nanosheets with 1T-phase and controlled layers represents a daunting challenge towards the device applications of MoS 2 . Conventional ion intercalation assisted exfoliation needs the use of hazardous n-butyllithium and/or elaborate control of the intercalation potential to avoid the decomposition of the MoS 2 . This work reports a facile strategy by intercalating Li ions electrochemically with ether-based electrolyte into the van der Waals (vdW) channels of MoS 2 , which successfully avoids the decomposition of MoS 2 at low potentials. The co-intercalation of Li + and the ether solvent into MoS 2 makes a first-order phase transformation, forming a superlattice phase, which preserves the layered structure and hence enables the exfoliation of bulk 2H-MoS 2 into bilayer nanosheets with 1T-phase. Compared with the pristine 2H-MoS 2 , the bilayer 1T-MoS 2 nanosheets exhibit better electrocatalytic performance for the hydrogen evolution reaction (HER). This facile method should be easily extended to the exfoliation of various transition metal dichalcogenides (TMDs).