Room-temperature sodium-sulfur (Na-S) batteries are emerging as a promising next-generation energy storage technology, offering high energy densities at low cost and utilizing abundant elements. However, their practical application is hindered by the shuttle effect of sodium-polysulfides and the sluggish kinetics of sulfur redox reactions. In this study, we demonstrate a heteronuclear diatomic catalyst featuring Fe and Co bimetallic sites embedded in nitrogen-doped hollow carbon nanospheres (Fe-Co/NC) as an effective sulfur host at the cathode of Na-S batteries. Aberration-corrected high-angle annular dark field scanning transmission electron microscopy demonstrates the presence of isolated Fe-Co atomic pairs, while synchrotron radiation X-ray absorption fine structure analysis confirms the (Fe-Co-N