Kinetic Study of Hydrogen Evolution Reaction over Strained MoS2 with Sulfur Vacancies Using Scanning Electrochemical Microscopy

Molybdenum disulfide (MoS2), with its active edge sites, is a proposed alternative to platinum for catalyzing the hydrogen evolution reaction (HER). Recently, the inert basal of was activated and optimized plane MoS2 successfully with excellent intrinsic HER activity by creating and further straining sulfur (S) vacancies. Nevertheless, little is known about the HER kinetics of those S vacancies and the additional effects from elastic tensile strain. Herein, scanning electrochemical microscopy was used to determine the HER kinetic data for both unstrained S vacancies (formal potential E-v(0) = -0.53 V-Ag/AgCl, electron-transfer coefficient alpha(v) = 0.4, electron-transfer rate constant k(v)(0) = 2.3 X 10(-4) cm/s) and strained S vacancies (E-sv(0) = -0.53 V-Ag/AgCl, alpha(sv) = 0.4, k(sv)(0) = 1.0 X 10(-3) cm/s