High-throughput screening of dual-atom doped PC6 electrocatalysts for efficient CO2 electrochemical reduction to CH4 by breaking scaling relations

The catalytic activity of the CO2 electrochemical reduction reaction (CO2RR), which is regarded as one of the most promising approach to tackle the current excess carbon emissions problem, is significantly restricted by the scaling relationship between adsorption energy of reaction intermediates. Here, inspired by the concept of multiple active centers, we designed 36 dual-atom catalysts in PC6 monolayer, including 8 homonuclear (M2@PC6, M=Cr, Mn, Fe, Co, Ni, Cu, Pd, and Ag) and 28 heteronuclear (M1M2@PC6) catalysts, to obtain efficient CO2RR catalysts by breaking the inherent limitation of linear scaling relations. After several rounds of screening for catalysts with stability, activity, selectivity through density functional theory (DFT) study, Mn2@PC6 was identified as a promising candidate for deep reduction of CO2 to CH4 with a low limiting potential of -0.31V (vs RHE). The projected density of states analysis demonstrates that the candidates break the linear scaling relationship stemming from the apparent mixing of the O-2p states and metal-3d states. The apparent change of spin polarization and asymmetric charge distribution on the active site of Mn2@PC6 play a crucial role in its superior CO2RR catalytic performance. This work provides a potential strategy from the theoretical perspective for rational design of efficient electrocatalyst by introduction of dual active centers to break the scaling relationship of intermediates.