Computational screening of defective BC 3 -supported single-atom catalysts for electrochemical CO 2 reduction.

The electrochemical CO 2 reduction reaction (eCO 2 RR) 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 C 1 products (CO, HCOOH, CH 3 OH, and CH 4 ) remains a daunting task. In this study, we conducted comprehensive first-principles calculations to investigate the eCO 2 RR mechanism using B-defective BC 3 -supported transition metal single-atom catalysts (TM@BC 3 SACs). Initially, we evaluated the thermodynamic and electrochemical stability of the designed 26 TM@BC 3 SACs by calculating the binding energy and dissolution potential of the anchored TM atoms. Subsequently, the selectivity of the eCO 2 RR and hydrogen evolution reaction (HER) on stable SACs was determined by comparing the free energy change (Δ G ) for the first protonation of CO 2 with the Δ G 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 eCO 2 RR towards different C 1 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@BC 3 and Ag@BC 3 are -0.11 V and -0.14 V. CH 4 is a preferred product on Re@BC 3 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 CO 2 conversion to C 1 products.