Boosting Thermal Stability of Volatile Os Catalysts by Downsizing to Atomically Dispersed Species

High Resolution Image Download MS PowerPoint Slide Os-based catalysts present remarkable catalytic activity; however, their use has been limited by the undesirable side reactions that generate highly toxic and volatile OsO 4 even at room temperature. Herein, we demonstrate that the thermal stability of Os-based catalysts can be dramatically improved by downsizing Os nanoparticles (NPs) into atomically dispersed species. We observed that Os NPs were converted into OsO 4 after calcination at 250 °C followed by sublimation, whereas single Os sites retained their structure after calcination. Temperature-programmed oxidation analysis confirmed that Os NPs started to undergo oxidation at 130 °C, whereas atomically dispersed Os preserved its state up to 300 °C. The CO oxidation activity of the atomically dispersed Os catalyst at 400 °C (100% conversion) was stably preserved over 30 h. By contra…