Computational screening of defective BC3-supported single-atom catalysts for electrochemical CO2 reduction

Abstract

The electrochemical CO₂ reduction reaction (eCO₂RR) driven by renewable electricity offers a green and sustainable technology for synthesizing chemicals and managing global carbon balance. However, developing electrocatalysts with high activity and selectivity for producing C₁ products (CO, HCOOH, CH₃OH, and CH₄) remains a daunting task. In this study, we conducted comprehensive first-principles calculations to investigate the eCO₂RR mechanism using B-defective BC₃-supported transition metal single-atom catalysts (TM@BC₃ SACs). Initially, we evaluated the thermodynamic and electrochemical stability of the designed 26 TM@BC₃ SACs by calculating the binding energy and dissolution potential of the anchored TM atoms. Subsequently, the selectivity of the eCO₂RR and hydrogen evolution reaction (HER) on stable SACs was determined by comparing the free energy change (ΔG) for the first protonation of CO₂ with the ΔG of *H formation. The stability and selectivity screening processes enabled us to narrow down the pool of SACs to the 14 promising ones. Finally, volcano plots for the eCO₂RR towards different C₁ products were established by using the adsorption energy descriptors of key intermediates, and three SACs were predicted to exhibit high activity and selectivity. The limiting potentials (U_L) for HCOOH production on Pd@BC₃ and Ag@BC₃ are −0.11 V and −0.14 V. CH₄ is a preferred product on Re@BC₃ with U_L of −0.22 V. Elaborate electronic structure calculations elucidate that the activity and selectivity originate from the sufficient activation of the C–O bond and the strong orbital hybridization between crucial intermediates and metal atoms. The proposed catalyst screening criteria, constructed volcano plots and predicted SACs may provide a theoretical foundation for the development of computationally guided catalyst designs for electrochemical CO₂ conversion to C₁ products.