First-principles investigation of elemental doping effects on H₂ adsorption on Ni (111) surfaces

The interaction between H₂ molecules and Ni(111) surfaces doped with Al, Co, Cr, and Ti is fundamental to understanding hydrogen-related reactions, including adsorption and dissociation. Using first-principles calculations, we investigated how the presence of different dopant elements (Al, Co, Cr, Ti) influences H₂ adsorption behavior on Ni(111), where a surface Ni atom is substituted by a dopant atom. Our calculations show that the Co-doped surface exhibits the lowest adsorption energy (E_ads) for single H₂ molecule adsorption, indicating easier H₂ absorption compared to other doped surfaces under this condition. In contrast, the Cr-doped surface demonstrates the lowest E_ads for two or three H₂ molecules, highlighting its superior efficiency in multi-molecule adsorption. Furthermore, analysis of the partial density of states (PDOS) and electron density difference confirms that H₂ adsorption on doped Ni(111) surfaces is modulated by the electronic property variations of dopant atoms. Dopants influence the surface atomic structure, with Co, Cr, and Ti inducing significant changes in the local electronic environment, thereby promoting the hydrogen absorption process. These findings provide critical guidance for designing more hydrogen-corrosion-resistant materials.