Exploring Metal Doped B12N12 Nanocage as Single Atom Catalyst for CO2 Reduction to Formic Acid: A DFT- Driven Analysis

Abstract

The ever-rising levels of emission of carbon dioxide (CO2) into the atmosphere have become a significant environmental issue, causing global warming and ecological imbalance. Converting CO₂ into value-added chemicals through efficient catalytic routes represents a sustainable strategy to mitigate emissions while enabling carbon recycling. In this work, transition-metal-doped B₁₂N₁₂ nanocages are systematically investigated as single-atom catalysts (SACs) for CO₂ reduction to formic acid using density functional theory (DFT). Structural stability, electronic properties, charge transfer behavior, and catalytic performance of late 3d transition metals (Fe, Co, Ni, Cu, and Zn) doped on B₁₂N₁₂ were comprehensively analyzed by QTAIM, FMO, NBO and MEP analyses. Energetic and electronic analyses reveal that Fe, Co, and Ni form thermodynamically stable complexes with strong metal–cage interactions, whereas Cu and Zn exhibit weak physisorption. Among the studied complexes, Co@B₁₂N₁₂ demonstrates superior catalytic performance by simultaneously activating both CO₂ and H₂ molecules, as confirmed by adsorption energies, bond elongation and IRI analyses. The reduction of CO2 on Co@B12N12 is carried out by a Langmuir Hinshelwood reaction in two competing pathways: the formate and the carboxyl pathways. In comparison of energy profiles, the carboxyl route is kinetically and thermodynamically preferable and has lower activation barriers and thermodynamically feasible reaction steps.