Electrocatalytic Properties of Electrochemically‐Polymerized Metal‐Phenolic Networks.

Metal‐phenolic networks (MPNs) are a promising platform for developing new heterogeneous catalytic materials for water splitting technologies. This study systematically investigates the relationship between MPN composition and catalytic properties via electropolymerization of copper and cobalt combined with lignin, tannic acid, epigallocatechin‐3‐gallate (EGCG), and gallic acid polyphenols. We find that the choice of metal, size of polyphenol, and polymerization method have the greatest impact on the propensity of MPNs for catalyzing hydrogen evolution. For example, gallic acid‐based MPNs result in smoother surfaces with ~2 nm roughness, resulting in low surface area and lower average current densities compared to all other polyphenols tested. Cobalt‐based MPNs show higher current densities compared to copper, yet higher onset potentials. The results provide a map of design choices that can be used to increase the catalytic performance of new materials used in water electrolysis. [ABSTRACT FROM AUTHOR]