Modulating electronic by construction WS2/WN heterostructure coupled with N-doped carbon to boost alkaline seawater hydrogen production

The development of an efficient and durable non-precious electrocatalyst for alkaline seawater electrolysis is of great significance. Herein, two-dimensional (2D) lamellar heterostructure WS 2 /WN was dispersed on the carbon matrix (marked as WS 2 /WN@CM). The obtained WS 2 /WN@CM catalysts demonstrate exceptional performance in the hydrogen evolution reaction (HER) in alkaline freshwater (1.0 M KOH), alkaline simulated seawater (1.0 M KOH + 0.5 M NaCl) and alkaline natural seawater (1.0 M KOH + seawater), respectively, which achieved a low overpotential (92 mV, 95 mV and 113 mV) at 10 mA cm −2 and outstanding long-term durability at 200 mA cm −2 for 100 h. The catalyst benefits from the 3D carbon skeleton, which not only effectively prevents stacking of the 2D lamellar WS 2 /WN to fully utilize the active material, but also provides rapid electron transport. Moreover, stress effects at WS 2 /WN interfaces lead to distortions of torsion angles in the WS 2 lattice, thereby increasing crystal surface defects accompanied by an enhancement of electrical conductivity. Density functional theory (DFT) calculations combined with XPS evidence confirm the electronic structure reorganization of WS 2 /WN at interfaces, which optimizes the adsorption energy of specific intermediates. Additionally, WN captures many electrons from WS 2 , so the WN region favors the reduction reaction and thus enhances the HER process.