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

Abstract

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.