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 °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.