Graphene-Supported Cun (n = 5, 6) Clusters for CO2 Reduction Catalysis.

In recent years, driven by the swift progress in nanotechnology and catalytic science, researchers in the field of physical chemistry have been vigorously exploring novel catalysts designed to enhance the efficiency and selectivity of a broad spectrum of chemical reactions. Against this backdrop, Cu clusters supported on defective graphene (Cu_n@GR, where n = 5, 6) function as two-dimensional nanocatalysts, demonstrating exceptional catalytic activity in the electrochemical reduction of carbon dioxide (CO₂RR). A comprehensive investigation into the catalytic properties of these materials has been undertaken using density functional theory (DFT) calculations. By tailoring the configuration of Cu_n@GR, specific reduction products such as CH₄ and CH₃OH can be selectively produced. The product selectivity is quantitatively analyzed through free energy calculations. Remarkably, the Cu₅@GR catalyst enables the electrochemical reduction of CO₂ to CH₄ with a significantly low overpotential of -0.31 eV. Furthermore, the overpotential of the hydrogen evolution reaction (HER) is higher than that of the conversion of CO₂ to CH₄; hence, the HER is unlikely to interfere and impede the efficiency of CH₄ production. This study demonstrates that Cu₅@GR offers low overpotential and high catalytic efficiency, providing a theoretical foundation for the design and experimental synthesis of composite nanocatalysts.