Strain-Engineered Two-Dimensional MoS₂ for Enhanced Hydrogen Evolution Reaction: A Combined DFT and Experimental Study

Abstract

We demonstrate that biaxial tensile strain of 3-5% applied to monolayer MoS₂ dramatically enhances its electrocatalytic activity for the hydrogen evolution reaction (HER). First-principles density functional theory (DFT) calculations predict that 4% strain reduces the Gibbs free energy of hydrogen adsorption (ΔG_H*) from +0.09 eV (unstrained) to −0.02 eV, approaching the thermoneutral optimum. Experimentally, strained MoS₂ films on flexible polyimide substrates achieve an overpotential of 152 mV at 10 mA/cm² with a Tafel slope of 58 mV/dec, representing a 35% improvement over unstrained counterparts. In situ Raman spectroscopy confirms the strain state is maintained during electrochemical cycling.