“…Hydrogen, as a sustainable and clean energy vector, stands out as a viable substitute for fossil fuels, which not only contribute to environmental pollution but are also depleting worldwide. , The generation of green hydrogen via electrocatalytic water splitting, powered by renewable electricity, is a compelling approach, yet it is currently hampered by the reliance on costly noble metal electrocatalysts, such as Pt, for the cathodic hydrogen evolution reaction (HER). , MoS 2 , with its affordable cost and advantageous layered crystal structure, offers near-zero hydrogen adsorption energy (Δ G H* ) at its edges and defects, positioning it as a potential replacement for Pt in HER applications. − However, the practical catalytic activity of MoS 2 is often limited due to the inert nature of its basal plane toward HER, and its wide band gap hinders efficient charge transfer and electron mobility, thus constraining the catalytic process. , Strategic doping with heteroatoms has been recognized as an effective method to engineer MoS 2 by introducing defects and altering the host material’s intrinsic properties. , Among various dopants, selenium (Se) is particularly promising due to its high structural compatibility with MoS 2 , allowing for the creation of MoS x Se 2– x with a broad range of Se content. − Furthermore, Se’s lower electronegativity compared to sulfur can modulate the electronic structure of adjacent S atoms, potentially enhancing the catalytic performance of MoS 2 for HER applications.…”