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