Selective Introduction of Catalytic Sites on MoS ₂ for Hydrogen Evolution Reaction Using Laser Patterning

High Resolution Image Download MS PowerPoint Slide Engineering defects in two-dimensional transition metal dichalcogenides have emerged as a promising route to enhance their electrocatalytic activity toward the hydrogen evolution reaction. Here, we report a rapid and scalable laser patterning strategy to introduce controlled defects in MoS 2 transferred on highly oriented pyrolytic graphite substrates. Morphological and structural analyses by atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), scanning electron microscopy (SEM), Raman spectroscopy, and high-resolution transmission electron microscopy (HR-TEM) reveal that laser processing produces sulfur vacancies or amorphous edge-like defects in a laser power-dependent fashion. In particular, AFM/KPFM measurements indicate significant modifications of the surface potential even at lower laser doses, where no complete perforation occurs, suggesting subtle chemical changes that motivated further compositional studies. Complementary X-ray photoelectron spectroscopy and energy-dispersive spectroscopy analyses confirm sulfur depletion and partial oxidation around the ablated regions. Electrochemical measurements demonstrate that the sample treated with the lowest laser power exhibits the best performance, achieving an overpotential of ∼0.50 V and retaining stability after cycling. These results demonstrate that laser processing provides a versatile and selective platform to tailor the structural and electronic properties of MoS 2 on carbon substrates, enabling a scalable and stable approach for hydrogen generation.