Rational design single-atom doped Ti3C2O2 MXene as a promising catalyst for hydrogen evolution reaction

• DFT and AIMD analyses reveal HER activity and stability of nonmetal-doped Ti 3 C 2 O 2 . • ΔG H * calculations identify As-doped Ti 3 C 2 O 2 as optimal (0.215 eV). • AIMD simulations confirm the good dynamic stability of P- and As-doped Ti 3 C 2 O 2 . • Electronic structure analyses reveal nonmetal doping-induced local electronic modulation of Ti 3 C 2 O 2 . • Findings provide computational insights for electrocatalyst design strategies. Two-dimensional MXenes have attracted extensive interest as promising HER electrocatalysts. Using density functional theory, we investigate nonmetal-doped Ti 3 C 2 O 2 (NM = B, N, P, Si, As) to correlate hydrogen adsorption free energy ( ΔG H * ) with electronic structure, and provide a comprehensive analysis of reaction pathways, kinetic barriers, and thermal stability. Our results demonstrate that NM doping can efficiently tailor the electronic structure of Ti 3 C 2 O 2 . Among the five dopants, As-doped Ti 3 C 2 O 2 exhibits the most favorable ΔG H * value of -0.215 eV, which is significantly improved relative to pristine Ti 3 C 2 O 2 . Analysis of band structures, projected density of states, and charge transfer further reveals that nonmetal doping modulates the local electronic environment around the dopant sites in Ti 3 C 2 O 2 . Ab initio molecular dynamics (AIMD) simulation results suggest that the P- and As-doped Ti 3 C 2 O 2 possess good dynamic stability. These results indicate that NM doping serves as an effective strategy to develop Ti 3 C 2 O 2 ‐based electrocatalysts for HER.