Theoretical Screening of CO2 Electroreduction over MOF-808-Supported Self-Adaptive Dual-Metal-Site Pairs.

Electrochemical CO2 reduction to transportation fuels and valuable platform chemicals provides a sustainable avenue for renewable energy storage and realizes an artificially closed carbon loop. However, the rational design of highly active and selective CO2 reduction electrocatalysts remains a challenging task. Herein, a series of metal-organic framework (MOF)-supported flexible, self-adaptive dual-metal-site pairs (DMSPs) including 21 pairwise combinations of six transition metal single sites (MOF-808-EDTA-M1M2, M1/M2 = Fe, Cu, Ni, Pd, Pt, Au) for the CO2 reduction reaction (CO2RR) were theoretically screened using density functional theory calculations. Against the competitive hydrogen evolution reaction, MOF-808-EDTA-FeFe and MOF-808-EDTA-FePt were identified as the promising CO2RR electrocatalysts toward C1 and C2 products. The calculated limiting potential for CO2 electroreduction to C2H6 and C2H5OH over MOF-808-EDTA-FeFe is -0.87 V. Compared with an applied potential of -0.56 eV toward CH4 production over MOF-808-EDTA-FeFe, MOF-808-EDTA-FePt exhibits an even better activity for CO2 reduction to C1 products at a limiting potential of -0.35 V. The present work not only identifies promising candidates for highly selective CO2RR electrocatalysts leading to C1 and C2 products but also provides mechanistic insights into the dynamic nature of DMSPs for stabilizing various reaction intermediates in the CO2RR process.