Rational Design of Cluster-Modified MXene for Electrocatalytic High-Efficiency Hydrogen Evolution Reaction

To enable efficient and cost-effective hydrogen production from water splitting, transition-metal clusters (TMCs) loaded on various functionalized Ti₂CT₂ MXenes (TMCs/Ti₂CT₂) are systematically investigated as potential electrocatalysts for the hydrogen evolution reaction (HER) using first-principles calculations. The results indicate that 24 optimal combinations of functional groups and TMCs (e.g., Te–Co, Te–Rh, and Se–Ir) are screened from 223 candidates, which exhibit favorable stability and even lower |ΔG_H| than that of the noble-metal Pt benchmark (ΔG_H = −0.09 eV). Crucially, the enhanced activity originates from the electronegativity match between functional groups and TMCs, which induces uniform valence states across the cluster sites and thereby optimizes the hydrogen binding strength. Furthermore, a machine-learning framework with high predictive accuracy (R² = 0.89) is established to enable the rapid screening of TMCs/Ti₂CT₂ and reveal the correlation between their structural properties and HER catalytic activity. These findings not only provide promising HER electrocatalyst candidates but also elucidate the electronic origins of catalytic activity, offering a rational design strategy for TMCs/Ti₂CT₂.