The bio-inspired heterogeneous single-cluster catalyst Ni100-Fe 4 S 4 for enhanced electrochemical CO 2 reduction to CH 4

Electrochemical conversion of CO -to-CH is a process of converting the inert greenhouse gas into energy molecules. It offers great promise for the transformation of carbon-neutral economy. However, achieving high CH activity and selectivity remains a major challenge because the electrochemical reduction of CO -to-CH is accompanied by various C intermediates at the catalytic site, involving multiple proton-coupled electron transfer processes. Herein, different from the traditional designing strategy, we propose a bio-inspired theoretical design approach to construct a heterogeneous single-cluster catalyst Ni100-Fe S at the atomic level, which may show high CO electroreduction performance. Combined with the crystallographic data and theoretical calculations, Ni100-Fe S and CO dehydrogenase exhibit highly similar catalytic geometric active centers and CO binding modes. By exploring the origin of the catalytic activity of this biomimetic structure, we found that the activation of CO on Ni100-Fe S theoretically exceeds that on natural CO dehydrogenase. Density functional theory calculations reveal that the dehydrogenase enzyme-liked Fe-Ni active site serves as an electron enrichment 'electro-bridge' (an electron-rich highly active catalytic site), which can activate CO molecules efficiently and stabilize various intermediates in multistep elementary reactions to selectively produce CH at a low overpotential (0.13 eV). The calculated CO electroreduction pathways are well consistent with the nickel-based catalytic materials reported in experimental studies. Our work showcases and highlights the rational design of high-performance catalytic materials the biomimetic methodology at the atomic level.