Highly Crystalline Co Nanoparticles With Uniform Surface CoO x Nanoislands Derived From a Co–N 2 O 2 Precursor for Selective CO 2 Conversion

Converting CO 2 into useful chemicals is a cornerstone of sustainable chemistry; among viable routes, the reverse water‐gas shift (RWGS) reaction supplies CO for subsequent fuel and olefin synthesis, yet achieving simultaneously high CO selectivity, fast CO 2 activation, and stability with non‐noble metals remains elusive. Here, we employ a pure H 2 torrent to rapidly reduce a Co‐salophen framework, forging a core‐shell Co@CoO x ‐C catalyst consisting of a highly crystalline metallic Co core and a defect‐rich CoO x shell capable of dynamic reconstruction under redox conditions. The metallic Co core dissociates H 2 , driving hydrogen spillover to the metal‐oxide interface, where CO 2 is efficiently activated, resulting in selective CO formation at the highly active Co/CoO x boundary. Rapid CO desorption from coordinatively saturated CoO x sites suppresses further hydrogenation, affording >99% CO selectivity and a CO formation rate of 254.0 mmol g cat −1 h −1 at 500°C maintained for >100 h. These findings demonstrate that engineering dynamic Co/CoO x interfaces via H 2 torrent reduction overcomes the intrinsic selectivity limitations of cobalt‐based RWGS catalysts and highlight defect‐rich core‐shell structures derived from H 2 ‐reduced metal‐salophen precursors as a versatile platform for next‐generation CO 2 conversion technologies.