Doping C60 with single or dual fe atoms for nitrogen reduction reaction: a DFT study

Abstract In this work, we conducted a detailed investigation of the catalytic mechanism of the electrocatalytic nitrogen reduction reaction (NRR) by density functional theory (DFT) calculations, focusing on fullerene (C 60 ) doped with single or dual Fe atoms. The results indicate that single or dual Fe atoms can be stably embedded within defective C 60 , yielding Fe 1 C 59 and Fe 2 C 58 , respectively. Both catalysts exhibit excellent performance in the adsorption and activation of N 2 , with Fe 2 C 58 demonstrating a certain degree of superiority. Based on the investigation of the NRR reaction pathways on these catalysts, it has been found that, despite varying pathways in different systems, the rate-determining step (RDS) is consistently the first hydrogenation step *N 2 → *NNH. Both thermodynamic and kinetic analyses indicate that Fe 2 C 58 exhibits superior catalytic performance compared to Fe 1 C 59 . Specifically, the energy barrier for the RDS of the optimal reaction pathway on Fe 2 C 58 is only 0.690 eV. Additionally, Fe 2 C 58 also demonstrates an advantage in suppressing the competitive hydrogen evolution reaction (HER). The present work demonstrates that a catalyst composed of C 60 doped with dual Fe atoms exhibits superior stability, electrocatalytic activity, and selectivity for NRR compared to a catalyst doped with a single Fe atom. This research provides a foundation for the design and synthesis of other heteroatom-doped fullerene catalysts.