Highly Active Hydrogen Evolution Achieved by Microwave-Assisted Rapid Anchoring of Single Platinum Atom on S-Ti₃C₂T_x

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 Ti₃C₂T_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/Ti₃C₂T_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.