Influence of Composition-Phase Interplay on Electrochemical Activity of Ternary Transition Metal Dichalcogenides

Abstract

Alloying is a powerful strategy to tailor the electronic structures of 2D transition metal dichalcogenides. Controlling the functionalities is essential to explore full potential of these ternary nanosheets with tunable electronic properties. Here, Nb alloyed with W to form ternary NbxW1-xS2 nanosheets with different stoichiometric ratios were successfully controlled via colloidal hot-injection synthesis. Incorporation of Nb alters the band structures of parent WS2, allowing for controlled tunning of electronic properties. High resolution transmission electron microscopy reveals an irregular atomic arrangement at higher Nb concentrations, with a notable transition from pure 2H phase to mixed 2H-1T’ phase under controlled concentration of Nb content in the composition. Nb induces a shift of the fermi level, causing transition from semiconducting to metallic nature in ternary nanosheets which allowed for enhanced electrocatalytic activity for the hydrogen evolution reaction (HER) for Nb0.5W0.5S2 compared to pristine WS2.