Electronic structure engineering of Zr-doped Ti3C2 and Ti3CN MXenes for efficient hydrogen evolution reaction

Hydrogen production via the Hydrogen Evolution Reaction (HER) is crucial for sustainable energy, but its reliance on expensive Pt-based catalysts limits scalability. Here, we investigate the catalytic performance of Zr-doped Ti₃C₂ and Ti₃CN MXenes using first-principles density functional theory (DFT). Our results show that Zr doping at 3% and 7% significantly enhances HER activity by reducing the work function to the optimal range of 3.5–4.5 eV and achieving near-zero Gibbs free energy ($\left|\Delta G_{H^{\ast }}\right|$= 0.18–0.16 eV), ideal for efficient hydrogen adsorption and desorption. Bader charge analysis reveals substantial electron accumulation at Zr and N sites, facilitating charge transfer and improving catalytic performance. These findings establish Zr-doped MXenes as cost-effective, high-performance alternatives to noble metal catalysts, offering a scalable pathway toward green hydrogen production and next-generation electrocatalysts.