Exploring electronic and energy descriptors to identify the dual metal center catalyst for CO2ER towards C2 product

Abstract

The electrocatalytic CO2 reduction reaction (CO2ER) has sparked immense interest due to its potential to generate valuable multi-carbon (C2) products. The innovative dual active site catalysts (DACs), feature dual-atom sites that create the perfect geometric environment for two CO molecules to bond simultaneously. In this study, we spotlight transition metal (TM) dimers anchored on nitrogen-doped graphene, referred to as TM1TM2@NGr, as our primary focus. Analysing 54 candidates, we evaluate their stability via negative binding energy and ICOHP values, enhanced by ab initio molecular dynamics (AIMD) calculations. Three systems namely WIr@NGr, WFe@NGr, and WW@NG demonstrate remarkable selectivity for ethanol production due to their low free energy difference (∆G*CO dimer-2*CO) which offers low overpotentials of 0.47, 0.49, and 0.5 V, respectively. We analysed 71 electronic parameters to identify key factors influencing the free energy difference (∆G*CO dimer-2*CO) and found 12 electronic descriptors strongly correlated due to the Pearson correlation coefficient (r) larger than 0.8. Among these, the occupancy of the dxz orbital (dxz_occ), and the downward channels of dxz and dz2 orbitals (dxz_down_occ and dz2_down_occ) were the most effective for predicting the energy difference, demonstrating the highest r values. This highlights their importance as key descriptors for ∆G*COdimer-2*CO and corresponding C2 production. Furthermore, three DACs have been identified as highly effective for hydrogen evolution reactions (HER), while thirteen DACs show CO2ER to methane production. Our research offers vital insights into the catalytic mechanisms of DACs, paving the way for discovering cost-effective candidates for efficient CO2 conversion into valuable C2 products.