Bias-Adaptable CO2-to-CO Conversion via Tuning the Binding of Competing Intermediates

CO2 electroreduction powered by renewable electricity represents a promising method to enclose anthropogenic carbon cycle. Current catalysts display high selectivity toward the desired product only over a narrow potential window due primarily to unoptimized intermediate binding. Here, we report a functional ligand modification strategy in which palladium nanoparticles are encapsulated inside metal-organic frameworks with 2,2'- bipyridine organic linkers to tune intermediate binding and thus to sustain a highly selective CO2-to-CO conversion over widened potential window. The catalyst exhibits CO faradaic efficiency in excess of 80% over a potential window from -0.3 to -1.2 V and reaches the maxima of 98.2% at -0.8 V. Mechanistic studies show that the 2,2'- bipyridine on Pd surface reduces the binding strength of both *H and *CO, a too strong binding of which leads to competing formate production and CO poison, respectively, and thus enhances the selectivity and stability of CO product.

Automated summary

By modifying the catalyst with functional ligands, the study successfully adjusted the intermediate binding of the catalyst, achieving a highly selective CO2-to-CO conversion over a widened potential window. The catalyst exhibited over 80% CO faradaic efficiency in the range of -0.3 to -1.2 V, reaching a maximum of 98.2% at -0.8 V.