Synergism on Electronic Structures and Active Edges of Metallic Vanadium Disulfide Nanosheets via Co Doping for Efficient Hydrogen Evolution Reaction in Seawater

Abstract Seawater electrolysis with clean hydrogen energy has bright prospects due to the abundant reserves of seawater on our planet. However, the highly desirable direct seawater splitting with efficient electrocatalyst is still lacking. Herein, Co‐doped metallic VS 2 nanosheets with modulated electronic structures and numerous exposed edges were proposed and evaluated as superior catalysts for hydrogen evolution from seawater. The enlarged number of edges through reducing nanosheet size and enriching sulfur defects by Co doping contribute to numerous active sites exposed, leading to desirable catalytic performances. The Co‐doped VS 2 nanosheets with 10 % V substituted by Co exhibit excellent catalytic performance in simulated seawater with an onset potential of 196 mV and possesses long‐term stability without obvious current decay after 12‐h test. Moreover, this sample also delivers lower overpotentials of 234 mV at −10 mA cm −2 in acid media. The study can further broaden the development of vanadium chalcogenides in seawater catalysis.