Amaram, Ashutosh KrishnaAshutosh KrishnaAmaramRoy, AadityaAadityaRoyRanganathan, RaghavanRaghavanRanganathan2026-01-072026-01-072025-122331-842210.48550/arXiv.2512.23270http://repository.iitgn.ac.in/handle/IITG2025/33768The recent synthesis of Goldene, a 2D sheet of gold exfoliated from Ti_3AuC_2, offers high specific surface area (~260 m^2g^{-1}), roughly twice that of fine nanodots (~100 m^2g^{-1}), and unique electronic properties due to its dense d-orbital. In this work, we investigate the adsorption of single atom catalyst (SAC) of hydrogen atom on pristine goldene (pG), monovacant goldene (vG), and sulfur-functionalized variants (thiol-pG and thiol-vG) using ab initio calculations. The adsorption energy of a single H atom and \Delta G_H, determines the efficiency of the Volmer step of the hydrogen evolution reaction (HER) and is a key descriptor for HER activity. We explore various potential sites for H adsorption and its impact on descriptors such as Bader charges, d-band shift and the exchange current density.en-USDensity Functional Theory (DFT)Hydrogen Evolution Reaction (HER)2D MaterialsGoldeneE-print