Electroreduction of CO₂ on Cu, Fe, or Ni-doped Diamane Sheets: A DFT Study

Poor mass transfer behavior and inherent activity limit the efficiency of traditional catalysts in electrocatalyzing carbon dioxide reduction reactions. However, the development of novel nanomaterials provides new strategies to solve the above problems. Herein, we propose novel single-metal atom catalysts, namely diamane-based electrocatalysts doped with Cu, Fe, and Ni, explored through density functional theory (DFT) calculations. We thoroughly investigated the doping pattern and energetics for different dopants. Furthermore, we systematically investigated the conversion process of CO₂ to C₁ or C₂₊ products, utilizing the free energy analysis of reaction pathways. Our results reveal that dopants could only be introduced into diamane following a specific pattern. Dopants significantly enhance the CO₂ adsorption ability of diamane, with Fe and Ni proving notably more effective than Cu. After CO₂ adsorption, Cu- and Fe-doped diamane prefer to catalyze CO₂RR, while Ni-doped diamane favors hydrogen evolution reaction (HER). The C-C coupling reaction on Cu-hollow diamane, Cu-bridge diamane, and Fe-hollow diamane tends to be from C₂₊ products. Among all examined catalysts, Cu-hollow diamane shows better electro-catalytic performance. Our study demonstrates the feasibility of and contributes to the development of diamane-based electro-catalysts for CO₂RR.