Preparation and characterization of bifunctional 1T-2H MoS2-Sv/CuS catalyst for electrocatalytic hydrogen and oxygen evolution reaction

The two-dimensional transition-metal disulfide compounds, such as molybdenum disulfide (MoS2), have been identified as highly promising candidates for electrocatalytic water splitting. The performance of MoS2 in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is still inferior to that of precious metals. The rational design of the electrocatalyst structure is crucial for achieving bifunctional HER/OER reactions. Herein, the 1 T-2H molybdenum sulphide with sulfur vacancy/copper sulphide (1 T-2H MoS2-Sv/CuS) catalyst with dual functions of HER and OER was synthesized via a one-step hydrothermal method, utilizing prepared copper(I) oxide (Cu2O) as the precursor. The surface of MoS2 substrate generates sulfur vacancies (Sv), which enriches the active site. These Sv to the benefit of MoS2 phase transition from a stable 2H phase to a more catalytically active 1 T phase. The synergistic effect of 1 T MoS2 and copper sulphide (CuS) promotes the acceleration of electron transfer. The 1 T-2H MoS2-Sv/CuS material exhibits an overpotential of 85 mV in the HER at a current density of 10 mA cm−2, while it shows an overpotential of 100 mV in the OER at the same current density of 10 mA cm−2, with a Tafel slope of 67 mV dec-1. Additionally, 1 T-2H MoS2-Sv/CuS exhibits excellent stability in both HER and OER. The work provides a new strategy for constructing MoS2-based composites exhibiting dual-functional, highly efficient HER and OER performance.