Computational high-throughput screening of high-performance transition metal C₈N₈ single-atom electrocatalysts for the oxygen reduction reaction

Two-dimensional materials with active sites are expected to replace platinum as large-scale oxygen reduction reaction (ORR) catalysts. C₈N₈ as a novel 2D material demonstrates an excellent high pore ratio and structural tunability by embedding transition metal (TM) atoms into its periodic units to form TM-N4 subunits, exhibiting enormous catalytic potential in reactions such as the ORR. However, due to experimental cycles and traditional computational cost limitations, the ORR catalytic activity of TM-C₈N₈ monolayers with varying central metal atoms remains insufficiently investigated, which severely hinders the development of this material. In this study, we performed systematic investigations on various TM-C₈N₈ monolayers containing different central metals using combined density functional theory and high-throughput screening, exploring their interactions and catalytic mechanisms in the ORR. Our study demonstrates that d-band center modification avoids excessive intermediate adsorption, while the TM-C₈N₈-intermediate interaction strength governs ORR catalytic activity. From 38 screened materials, Fe-C₈N₈ and Mn-C₈N₈ emerged as two optimal candidates; both materials exhibit exceptional thermodynamic and electrochemical stability, with Fe-C₈N₈ demonstrating particularly remarkable performance, achieving an outstanding overpotential of merely 0.26 V. This study guides the design of efficient ORR electrocatalysts and clarifies the reaction mechanism in TM-C₈N₈.