Unlocking the potential of p-block single-atom anchored on the MXene electrocatalyst surface for efficient CO₂...

The electrochemical reduction of CO₂ into value-added products has emerged as a promising approach for mitigating CO₂ emissions. In this study, 23 p-block single-atom (PSA) anchored onto the Mo₂CO₂ catalyst for CO₂ reduction have been systematically investigated using density functional theory at the atomic level. Based on the binding energy and cohesive energy, 9 PSA prefer to anchor onto the Mo₂CO₂ hollow carbon site. Side-on and end-on modes are preferred for CO₂ adsorption on PSA anchored Mo₂CO₂ (PSA@Mo₂CO₂). Projected density of states (PDOS) analysis indicates that PSA@Mo₂CO₂ exhibits a metallic-like electronic structure. The Bader charge analysis and charge density difference show unique behavior for Sn@Mo₂CO₂, with a lower Gibbs free energy change for the potential-determining step, CO₂ to *OCHO (0.58 eV). Sn@Mo₂CO₂ is located on top of the volcano plot of limiting potential versus adsorption energy. Furthermore, Sn@Mo₂CO₂ exhibits the highest selectivity for CO₂ reduction to HCOOH and suppresses the competing hydrogen evolution reaction. PDOS analysis of the *OCHO intermediate reveals that the oxygen and Sn p orbitals show moderate overlap. Ab initio molecular dynamics simulations indicate that Sn@Mo₂CO₂ is stable at 300 K. This work provides an orbital-based strategy for catalyst design to enable selective CO₂ reduction to HCOOH.