Synergistic Effects of Amine Functional Groups and Enriched-Atomic-Iron Sites in Carbon Dots for...

Metal phthalocyanine molecules with Me-N₄ centers have shown promise in electrocatalytic CO₂ reduction (eCO₂R) for CO generation. However, iron phthalocyanine (FePc) is an exception, exhibiting negligible eCO₂R activity due to a higher CO₂ to ^*COOH conversion barrier and stronger ^*CO binding energy. Here, amine functional groups onto atomic-Fe-rich carbon dots (Af-Fe-CDs) are introduced via a one-step solvothermal molecule fusion approach. Af-Fe-CDs feature well-defined Fe-N₄ active sites and an impressive Fe loading (up to 8.5 wt%). The synergistic effect between Fe-N₄ active centers and electron-donating amine functional groups in Af-Fe-CDs yielded outstanding CO₂-to-CO conversion performance. At industrial-relevant current densities exceeding 400 mA cm^-2 in a flow cell, Af-Fe-CDs achieved >92% selectivity, surpassing state-of-the-art CO₂-to-CO electrocatalysts. The in situ electrochemical FTIR characterization combined with theoretical calculations elucidated that Fe-N₄ integration with amine functional groups in Af-Fe-CDs significantly reduced energy barriers for ^*COOH intermediate formation and ^*CO desorption, enhancing eCO₂R efficiency. The proposed synergistic effect offers a promising avenue for high-efficiency catalysts with elevated atomic-metal loadings.