Enhanced HER Efficiency of Monolayer MoS2 via S Vacancies and Nano‐Cones Array Induced Strain Engineering

Abstract Molybdenum disulfide (MoS 2 ) has gained significant attention as a promising catalyst for hydrogen evolution reaction (HER). The catalytic performance of MoS 2 can be enhanced by either altering its structure or regulating external conditions. In this study, a novel approach combining the introduction of sulfur vacancy ( V S ) and biaxial tensile strain to create more active sites and modulate the band structure of monolayer MoS 2 is proposed. To achieve the desired strain level, nano‐cones (NCs) array substrates facilely fabricated by dip‐pen nanolithography (DPN) are employed. The magnitude of the applied tensile strain can be finely tuned via adjusting the height of the NCs. Furthermore, on‐chip electrochemical devices are constructed based on artificial structures, enabling precise optimization of HER performance of MoS 2 through the synergistic effect of V S and strain. Combined with the d‐band theory, it reveals that the HER properties of V S ‐MoS 2 are highly dependent on the degree of tensile strain. This study presents a promising avenue for the design and preparation of high‐performance 2D catalysts for energy conversion and storage applications.