Precisely Assembly of Individual‐Atom‐to‐Twinned Ruthenium Nanocrystal for Seawater Hydrogen Evolution

Atomic manufacturing technology can precisely control individual atoms to dynamically regulate atomic networks and provide a transformative approach for sustainable catalysis and energy fields. In this study, we report fluorine‐substituted graphdiyne (FGDY) as a promising platform for the gradual assembly of ruthenium (Ru) metal atoms from individual atoms to clusters, ultimately yielding twinned quantum dots (TQDs). Theoretical and experimental results show that FGDY, with a unique sp–sp 2 hybridized network and fluorine‐induced charge polarization, enhances Ru∼FGDY interactions, precisely controlling the atomic‐level dispersion of Ru while suppressing Ru aggregation and promoting active site exposure. These advantages further accelerate proton‐coupled electron transfer, reduce water dissociation barriers, and achieve excellent hydrogen evolution reaction (HER) activity (84 mV at 1.0 A cm −2 ) and stability (1200 h with negligible activity decay) in simulated seawater. This work provides a general platform for designing scalable, nonprecious metal catalysts for sustainable hydrogen production from complex electrolytes.