Optimizing CO2RR selectivity on single atom catalysts using graphical construction and identification of energy descriptor

The electrocatalytic reduction of CO2 (CO2RR) into value-added hydrocarbons is limited due to high limiting potential (U-L) and competing hydrogen evolution reaction (HER). To find the best catalyst for CO2 reduction the concept of hydrogen poisoning was not considered in the catalyst screening process. Herein, we present a simple screening method and graphical construction using multiparameter optimization for the design of highly active and selective single-atom catalysts (SAC) using density functional theory calculations. A series of SAC namely, MN4, MBN3 and H@MBN3 (M: metal) are investigated for CO2RR. Our results revealed that MN4 and MBN3 SAC are not favorable for CO2RR due to high U-L > -0.85 V and hydrogen poisoning (?G(H*) < 0), respectively. H@MBN3 SAC (stable compounds forming H-B bonds) are identified as efficient catalysts with a low value of U(L )and significantly hinder the competitive HER. Among these, H@CoBN3 and H@FeBN3 SAC show excellent CO2RR activity with limiting potential -0.30 and -0.44 V respectively for CH4 production and no chance of HER. Scaling relations reveal the importance of *COOH/*CHO binding energy (E-b) as an energy descriptor to evaluate the catalytic performance. This work provides a new theoretical perspective to design a highly selective catalyst for CO2RR.