Revealing well-defined cluster-supported bi-atom catalysts for enhanced CO electroreduction: a theoretical investigation.

It remains a great challenge to explore high-performance electrocatalysts for the CO reduction reaction (CO2RR) with high activity and selectivity. Herein, we employ first principles calculations to systematically investigate an emerging family of extended surface catalysts, bi-atom catalysts (BACs), in which bimetals anchored on graphitic carbon nitride (g-CN), for the CO2RR; and propose a novel framework to boost the CO2RR incorporation with well-defined clusters. Among 28 BACs, five candidates (Cr, CrFe, Mn, MnFe and Fe/g-CN) are first selected with efficient CO activation and favorability for CO reduction over H evolution. Fe@g-CN is then served as a superior electrocatalyst for the CO2RR with low limiting potentials () of -0.58 and -0.54 V towards C and C products. Intriguingly, the CO2RR performance of pure Fe@g-CN could be controlled by tunable Fe atomic cluster integration. In particular, the presence of an Fe cluster could strengthen the CO adsorption, effectively deactivate H, and intriguingly break the adsorbate (CO* and CHO*) scaling relation to achieve the distinguished CO2RR with a lowered to -0.45 V for the C mechanism, which is attributed to the exceptional charge redistribution of bimetals modulated by Fe. Our findings might open up possibilities for the rational design of BACs towards the CO2RR and other reactions.