CO2 Reduction Reactivity on the SiC Monolayer with Doped Topological Defects

Abstract

This study explores the catalytic properties of boron- and nitrogen-doped 585 extended line defects (585-ELD) in SiC monolayers for the CO₂ reduction reaction (CO₂RR). Using Density Functional Theory and ab initio Molecular Dynamics (AIMD) simulations, we analyze the stability, electronic structure, and adsorption characteristics of each doped defect. The results indicate that all doped systems, except for N–N, exhibit significant kinetic and thermodynamic stability, with midgap states that enhance electron availability and catalytic activity. Among the doped structures, the C–B ELD system uniquely balances CO₂ protonation and H₂ desorption, selectively favoring CO₂ reduction over hydrogen evolution. Calculated reaction free energies show that CH₄ formation is possible if the transition from H₂COH to CH₂ occurs, with a limiting potential (U_L) of 0.73 V, while strong interactions between H₂COH and the surface make CH₃OH formation energetically challenging. These findings position the C–B ELD SiC system as a promising candidate for efficient and selective CO₂ conversion, enabling the formation of valuable hydrocarbons and oxygenates through effective charge transfer and controlled reaction pathways.