Tracking the Formation of Atomically Dispersed Co-NC Catalyst via Operando XAFS

Single-atom catalysts (SACs) have recently attracted extensive attention attributed to their extremely high atom utilization and unique configuration. Meanwhile, high-temperature pyrolysis is indispensable for synthesizing metal and nitrogen-doped carbon catalysts. However, the rational design of SACs is hindered by the lack of understanding of evolutionary paths during pyrolysis due to uncontrollable factors. Here operando X-ray absorption fine structure (XAFS) spectroscopy combined with comprehensive analysis under heating conditions was conducted to monitor the structural evolution of Co-NC formatting. The pyrolysis procedure of the CoCl2 precursor to the Co-N4 moiety was thoroughly identified by confirming two key turning points at 300 and 700 degrees C. These results demonstrate that temperature greatly affects structural changes during the formation of SACs, providing a new perspective for the controllable design and synthesis of high-performance SACs.