Abstract
Proton exchange membrane water electrolysis stands as a promising technology for sustainable hydrogen production, although its viability hinges on minimizing platinum (Pt) usage without sacrificing catalytic efficiency. Central to this challenge is enhancing the intrinsic activity of Pt while ensuring the stability of the catalyst. We herein present a Mo(2)TiC(2) MXene-supported Pt nanocluster catalyst (Mo(2)TiC(2)-Pt(NC)) that requires a minimal Pt content (36 μg cm(-2)) to function, yet remains highly active and stable. Operando spectroscopy and theoretical simulation provide evidence for anomalous charge transfer from the MXene substrate to Pt(NC), thus generating highly efficient electron-rich Pt sites for robust hydrogen evolution. When incorporated into a proton exchange membrane electrolyzer, the catalyst affords more than 8700 h at 200 mA cm(-2) under ambient temperature with a decay rate of just 2.2 μV h(-1). All the performance metrics of the present Mo(2)TiC(2)-Pt(NC) catalysts are on par with or even surpass those of current hydrogen evolution electrocatalysts under identical operation conditions, thereby challenging the monopoly of high-loading Pt/C-20% in the current electrolyzer design.