2H → 1T Phase Change in Direct Synthesis of WS2 Nanosheets via Solution-Based Electrochemical Exfoliation and Their Catalytic Properties

Metallic 1T-WS2 has various interesting properties such as increased density of catalytically active sites on both the basal planes and edges as well as metallic conductivity which allows it to be used in applications such as biosensing and energy devices. Hence, it is highly beneficial to develop a simple, efficient, and low-cost synthesis method of 1T-WS2 nanosheets from commercially available bulk 2H-WS2. In this study, we reported WS2 nanosheets synthesized directly from bulk WS2 via solution-based electrochemical exfoliation with bipolar electrodes and investigated their electrocatalytic performances toward hydrogen evolution and oxygen reduction reactions. We successfully synthesized WS2 nanosheets of regular hexagonal symmetry with a 2H → 1T phase transition. This represents a novel method of producing 1T-WS2 nanosheets from bulk 2H-WS2 without compromising on its electrocatalytic properties.