Spatial and mechanistic elucidation of distance tunable Ru dual atom catalysts for efficient CO hydrogenation to ethanol.

Syngas-to-ethanol conversion is economically attractive yet remains challenging due to limited activity and selectivity under practical conditions. Achieving selective C-C coupling and directing *CHO hydrogenation to ethanol require precise control of active-site geometry and electronics. Here we use a coordination-precursor-mediated strategy to construct Ru dual-atom catalysts on N-coordinated carbon supports with tunable local architectures, where the Ru-Ru separation serves as a primary descriptor-together with coordination environment and intersite electronic coupling-governing cooperative CO/H2 activation and C-C bond formation. Varying the interatomic distance modulates geometric confinement and electronic interactions, improving ethanol formation. Within the optimal reaction window, the catalyst with the shortest Ru-Ru distance exhibits high CO conversion, high ethanol selectivity among oxygenated products, with oxygen-free hydrocarbon products excluded from the selectivity normalization, and stable operation at 1.0 MPa. In situ spectroscopy and DFT reveal that short Ru-Ru spacing enhances d-orbital hybridization and confinement, facilitating synergistic back-donation that lowers the C-C coupling barrier; Bader/charge-density analyses indicate preferential stabilization of hydroxylated intermediates toward ethanol. This work highlights distance-tuned dual-atom cooperativity as a key lever for selective syngas-to-ethanol catalysis.