Hydrothermal synthesis of ternary MoS2xSe2(1−x) nanosheets for electrocatalytic hydrogen evolution

Abstract

Transition metal dichalcogenides have shown promise as highly efficient hydrogen evolution reaction (HER) electrocatalysts. In this work, we demonstrate a one-pot hydrothermal synthesis of ternary 2H-MoS_2xSe_2(1−x) nanosheets for enhanced hydrogen production. Compared to pristine 2H-MoSe₂ and 2H-MoS₂, introduction of a third element not only expands the interlayer spacing, but also provides more active catalytic sites and lowers the charge transfer resistance. As a consequence, MoS_2xSe_2(1−x) exhibits a high electrocatalytic HER activity with a low overpotential of 188 mV vs. a RHE to achieve a geometric current density of −10 mA cm⁻² and a low Tafel slope of 43 mV dec⁻¹ in 0.5 M H₂SO₄. This study provides valuable insights that ternary structure formation can be effective for the preparation of high-performance HER electrocatalysts.