2D heterogeneous vanadium compound interfacial modulation enhanced synergistic catalytic hydrogen evolution for full pH range seawater splitting

Abstract

A novel electrocatalytic material VS₂@V₂C was proposed for the first time and successfully prepared by a one-step hydrothermal method. T-VS₂ nanosheets were uniformly and vertically embedded on the V₂C (MXene) matrix with a fewer layer structure. Owing to the fast charge transfer process at the interface of the two-phase structure and good conductivity, the composite material showed a lower hydrogen evolution overpotential and a very low Tafel slope in highly alkaline and highly acidic electrolytes (164 mV and 47.6 mV dec⁻¹ in 1.0 M KOH; 138 mV and 37.9 mV dec⁻¹ in 0.5 M H₂SO₄) under a current density of 20 mV cm⁻². More importantly, high-efficiency and stable electrolysis of seawater was achieved at a current density greater than 100 mA cm⁻², and the catalytic performance was significantly better than that of platinum-based alloys. First-principles calculations mechanically confirmed that VS₂@V₂C had higher carrier mobility and lower free energy of hydrogen adsorption. The VS₂ nanosheets that grew outwards could provide support to avoid agglomeration on the catalyst surface and the edge sulfur sites of VS₂ could promote the binding of adsorbed hydrogen atoms and the desorption of hydrogen molecules. Our work is expected to provide a valuable reference for the design and synthesis of the structure of industrial catalysts for hydrogen production from seawater in the future.