Enhancing CO₂ Methanation by Constructing Tetra-Atomic Catalysts on Graphdiyne

As an emerging two-dimensional material, graphdiyne (GDY) has attracted significant attention due to its distinctive porous architecture and acetylenic linkages. However, current research primarily focuses on catalytic systems with single- or dual-metal atom configurations for various reduction reactions. This study employs density functional theory (DFT) to systematically investigate the stability and catalytic activity of 4M-GDY (4 M = 4Sc, 4Ti, 4 V, 4Cr, 4Mn, 4Fe, 4Co, 4Ni, 4Cu, 4Zn). Computational results reveal that the 4M-GDY systems exhibit significant deep reduction propensity, with the 4Co-GDY configuration demonstrating particularly promising performance in the CO₂ reduction reaction (CRR), achieving a limiting potential of -0.46 V for methane (CH₄) production. Through comparative calculations of magnetic moments across different catalyst systems, we have discovered that magnetic moment can serve as an effective descriptor for CRR product selectivity in 4M-GDY catalyst systems. The unique tetra-metallic configuration provides an expanded structural platform for precise electronic structure modulation through metal composition engineering, enabling rational screening of high-efficiency catalysts for selective CH₄ generation. This work establishes a theoretical foundation for designing multimetallic GDY-based electrocatalysts with tailored catalytic properties.