Formamide-derived "glue" for the hundred-gram scale synthesis of atomically dispersed iron-nitrogen-carbon electrocatalysts.

The distinct structure and maximum utilization of metal atoms on supported single-atom catalysts (SACs) represents a new frontier of heterogeneous catalysis, yet the low-cost mass production of high-performance SACs is still a key issue for practical applications. Herein, by coating a formamide-derived highly N-modified carbonaceous layer as a "glue" on commercially available activated carbon black (AC), a hundred-gram scale synthesis of atomically dispersed non-noble metal-nitrogen-carbon (MNC) materials was realized, including but not limited to Fe, Co, Ni, Mn, and Cu. The dispersion and coordination environments of Fe atoms on AC were initially revealed by XRD, HRTEM, and XPS, and further confirmed by HAADF-STEM and XANES analysis, presenting Fe atoms in a Fe-N structure. The atomically dispersed metal species, though relatively low-loading grafted on AC (typical loading of 0.16 to 0.29 at%), are mostly distributed on the electrochemically accessible surface, resulting in improved metal utilization. The FeNC@AC-3 sample exhibited highly comparable catalytic performance to 20 wt% Pt/C for the alkaline oxygen reduction reaction, and superior Al-air battery performance. Our work may inspire the synthesis of other types of SACs for broad electrocatalysis applications at kilogram or even ton scale.