Stability and catalytic performance of Single-Atom catalysts supported on BN-ixene nanosheets for Hydrogen Adsorption, Dissociation, and CO 2 reduction reaction to formic acid

Catalytic hydrogenation of carbon dioxide to formic acid (CO 2 +H 2 → HCOOH) is a promising route for CO 2 utilization and sustainable fuel production. In this study, a series of ten transition-metal single-atom catalysts (Sc–Zn) supported on BN-ixene were systematically investigated using density functional theory to evaluate their stability, electronic properties, and catalytic performance. Interaction energy analysis confirms the strong stability of TM@BN-ixene systems, with values ranging from –2.32 to –0.20 eV. Among the studied catalysts, Sc- and Fe-decorated BN-ixene exhibit superior activity, delivering low activation barriers for hydrogen dissociation of 0.39 and 0.37 eV, respectively. Reaction energetics indicate that the formation of adsorbed atomic hydrogen (2H*) is thermodynamically favored over molecular adsorption (H 2 *), facilitating subsequent hydrogenation steps. Mechanistic analysis reveals that CO 2 hydrogenation proceeds via distinct pathways depending on the metal center, with the Langmuir–Hinshelwood (LH) pathway on Sc@BN-ixene with an activation barrier of 1.20 eV, which is slightly more favorable than the Eley–Rideal (ER) pathway on Fe@BN-ixene (1.24 eV). These findings provide critical mechanistic insights into CO hydrogenation on BN-ixene- supported single-atom catalysts and highlight their potential as cost-effective and efficient platforms for carbon capture and conversion.