Coordination Modulated Nonplanar Penta Graphene as the Electronic Structural Lever for CO2RR Activity and Selectivity in Dual Atom Catalysts

Abstract

Electrocatalysts featuring distinct coordination environments can achieve markedly enhanced activity toward the CO2 reduction reaction (CO2RR) through modulation of the electronic structure at their active sites. Therefore, elucidating the intrinsic properties of active centers in diverse coordination environments is crucial for the rational structural design of such catalysts. Using the nonplanar pentagonal lattice of penta-graphene (PG), which contains three types of coordinatively distinct carbon atoms, we create vacancy defects that anchor homonuclear pairs of 3d metals, thereby generating a family of PG-based dual-atom catalysts (DACs) with systematically varied coordination motifs that act as an electronic structural lever for CO2RR activity and selectivity. Allowing for ferromagnetic (FM), antiferromagnetic (AFM) and nonmagnetic (NM) spin states, we examine 86 DAC configurations by first-principles calculations and identify 35 thermodynamically stable structures, from which we screen catalysts that combine low overpotentials (η) with strong selectivity toward HCOOH formation. Mn- and Fe-based PG DACs achieve η as low as 0.157 V and 0.091 V, respectively, while effectively suppressing the competing hydrogen evolution reaction (HER). To rationalize these trends, we develop an interpretable machine learning model trained on structural and electronic descriptors, which attains an R2 value of 0.85 with an RMSE of about 0.10 V and, through Shapley value-based feature importance analysis, identifies the Bader charge of the metal centers as the dominant descriptor of η, indicating that coordination primarily determines CO2RR performance. These results establish a clear quantitative link between coordination environment, electronic structure and CO2RR performance in PG-based DACs and provide design guidelines for tailoring coordination to optimize activity and selectivity.