High-Throughput Screening of Single-Atom Catalyst Coordination Environment Regulation for CO2 Reduction Reactions

Recent studies have demonstrated that precise modulation of the coordination environment around metal centers can significantly influence the catalytic activity, inspiring interest in the rational design of efficient CO2 reduction reaction (CO2RR) catalysts through coordination engineering. In this work, a series of single-atom catalysts (SACs) with asymmetric coordination environments were systematically constructed based on heteroatom-doped graphene frameworks, aiming to elucidate the structure-activity relationships governing CO2RR performance. By integrating density functional theory (DFT) calculations with machine learning (ML) approaches, the limiting potential (UL) was employed as the target descriptor. EXtreme Gradient Boosting Regression (XGBR) and Sure Independence Screening and Sparsifying Operator (SISSO) algorithms were adopted to construct a black-box predictive model. An interpretable descriptor model, achieving coefficients of determination of R2 = 0.96 and R2 = 0.95, respectively, validated the reliability and generalizability of the established models. The results revealed that, compared to conventional M-N4 SACs with symmetric coordination environments, the introduction of asymmetric coordination could further enhance the CO2RR catalytic activity of Co-, Fe-, and Mn-based SACs, with notable performance variations across different metal centers. Four SACs with superior catalytic potential, namely, Co-N3O, Co-N3S, Fe-N4O2, and Mn-N4N3, were identified. Electronic structure analysis indicated that coordination environment modulation drove an upshift of the metal center d band toward the Fermi level, strengthening interactions with key reaction intermediates and optimizing adsorption energies to enhance catalytic activity. The DFT-ML strategy established herein provides a systematic framework for the rational design of SACs toward efficient CO2RR and offers generalizable principles for coordination engineering in electrocatalysis.