2D-Heterogeneous Vanadium Compound Interfacial Modulation Enhanced Synergistic Catalytic Hydrogen Evolution for Full pH Range Seawater Splitting
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 a V2C (MXene) matrix with a less layer structure. Thanks to the fast charge transfer process at the interface of the two-phase structure and the good conductivity, the composite material showed a lower hydrogen evolution overpotential and a very low Tafel slope in high alkaline and high acid electrolytes (164 mV, 47.6 mV/dec in 1.0 M KOH; 138 mV, 37.9 mV/dec in 0.5 M H2SO4) under the density the current of 20 mV cm-2. More importantly, high-efficiency and stable electrolysis of seawater were 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 have mechanically confirmed that VS2@V2C has higher carrier mobility and lower free energy of hydrogen adsorption. The VS2 nanosheets that grow outwards can provide support to avoid the agglomeration on the catalysts surface and the edge sulfur sites of VS2 can 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.