Efficient CO 2 Capture and In Situ Electrocatalytic Conversion on Heavy Metal-Doped Graphene Surface: A Comprehensive DFT Study

The recovery of heavy metals and the capture and conversion of CO 2 are both highly energy-intensive processes. Nevertheless, they exhibit considerable synergistic potential, and integrating these technologies presents a promising approach for improving environmental sustainability while lowering operational costs. In this study, we utilized density functional theory (DFT) calculations to elucidate the mechanism through which nitrogen-doped graphene (NG) surfaces simultaneously capture five heavy metal atoms from coal-fired power plant flue gas and catalyze the in situ electrochemical reduction of CO 2 to CH 3 OH and CH 4 . Calculations of electronic properties reveal that the NG surface exhibits strong binding affinity toward all investigated heavy metals except Hg. Analysis of reaction pathways indicates that Cd@C–N 4 demonstrates the minimal overpotential (0.32 eV) among the examined systems. This study, underpinned by density functional theory calculations, illustrates the feasibility of simultaneously attaining heavy metal recovery and electrocatalytic CO 2 reduction. Additionally, it offers a theoretical framework for employing NG adsorbents to capture and stabilize heavy metals in coal-fired power plants, along with their subsequent use for in situ CO 2 electrocatalysis.