High Active and Durable Vanadium Sulfide Multilayer Structure Featuring Rich Hole Defects Constructed for Accelerated Hydrogen Evolution Reaction

Abstract

VS2 nanomaterials with special morphology, exposed edges, defects have studied as an active and inexpensive electrocatalyst for hydrogen evolution reaction (HER). Here, we reported the fabrication of multilayer Waffle structured VS2 featuring rich hole defects (VS2 MLW). This structure shows excellent kinetic metrics for electrocatalytic HER, exhibiting a overpotential of 82 mV at the current density of −10 mA cm−2, a Tafel slope of 61 mV dec−1, and a long-term stability without any current fading. Its HER performance is much better than that of other V-based catalysts, and even comparable to that of commercial Pt/C. Through experimental and theoretical calculation, the outstanding electrocatalytic activity of the VS2 MLW is attributed to its special morphology and electronic structure. The hole defects in this structure provide larger electrochemical active area and more active sites for HER, more importantly, hole defects change the electron structure of catalyst and reduce the free energy of hydrogen adsorption, the optimized free energy consequently leading to the improved inherent catalytic activity of VS2 MLW. This work provides a new concept to design efficient HER catalyst by specific surface area and defect engineering.