Volume 65

DFT Study on the Regulatory Mechanism of Terminal Groups (-O, -F) in Tuning the Hydrogen Evolution Reaction Performance of Single-Atom Pt Anchored on Ti₃C₂Tₓ MXene Dezheng Guo, Zhixun Xiong, Yuan Gao

Abstract

In this work, density functional theory (DFT) calculations were carried out to investigate the effect of surface terminations (-O and -F) on the hydrogen evolution reaction (HER) performance of single-atom Pt anchored Ti₃C₂Tₓ MXenes. The optimized structures reveal that surface functionalization induces subtle distortions of the lattice and modifies the electronic properties of the substrate. Gibbs free energy calculations show that bare Ti₃C₂ binds hydrogen too strongly (ΔGH*= –1.16888 eV), while Pt anchoring significantly weakens the binding (-0.89759 eV). Surface terminations further regulate the adsorption strength, with saPt-Ti₃C₂O₂ (-0.82934 eV) and saPt-Ti₃C₂F₂ (0.678677 eV) progressively approaching thermoneutrality. Projected density of states (PDOS) analysis demonstrates that O and F terminations downshift the Pt d-band center and reduce the density of states near the Fermi level, correlating with weaker Pt-H interactions. Charge density difference (CDD) plots further confirm that electron withdrawal by O and F enhances Pt electron deficiency, tuning the interfacial charge transfer and Pt-H bonding characteristics.

Keywords DFT, Terminal groups, HER, MXene, Pt