Highly Active Hydrogen Evolution Achieved by Microwave‐Assisted Rapid Anchoring of Single Platinum Atom on S‐Ti ₃ C ₂ T <i> _x </i>

MXenes feature high surface area, a distinctive two‐dimensional layered architecture, and abundant surface terminations, establishing them as ideal supports for single‐atom catalysts (SACs). Herein, we employ a rapid microwave‐assisted strategy to anchor individual platinum (Pt) atoms onto poly(ionic liquid) (PIL)‐modified Ti 3 C 2 T x nanosheets, systematically elucidating the PIL’s critical role in directing Pt single‐atom nucleation. Advanced microscopic characterization confirms the uniform dispersion of isolated Pt species without detrimental nanoparticle aggregation. Comprehensive X‐ray absorption fine structure (XAFS) and near‐edge spectroscopy (XANES) analyses reveal the precise electronic structure and local coordination environment of Pt, demonstrating predominant anchoring at sulfur sites on the functionalized MXene surface, a structural motif further corroborated by density functional theory (DFT) calculations. The resulting Pt SA ‐S/Ti 3 C 2 T x ‐PIL electrocatalyst delivers exceptional hydrogen evolution reaction (HER) performance, requiring remarkably low overpotentials of 35 and 87 mV to drive current densities of 10 and 100 mA cm −2 , respectively. Moreover, the engineered sulfur‐rich surface significantly enhances long‐term operational durability, sustaining stable catalytic activity throughout 60 h of continuous electrolysis. Collectively, this study demonstrates that targeted PIL‐mediated surface engineering successfully introduces reactive sulfur terminations that simultaneously optimize HER reaction kinetics and provide thermodynamically robust coordination sites for atomic Pt anchoring.