Why surface hydrophobicity promotes CO electroreduction: a case study of hydrophobic polymer -heterocyclic carbenes.

We report the use of polymer -heterocyclic carbenes (NHCs) to control the microenvironment surrounding metal nanocatalysts, thereby enhancing their catalytic performance in CO electroreduction. Three polymer NHC ligands were designed with different hydrophobicity: hydrophilic poly(ethylene oxide) (PEO-NHC), hydrophobic polystyrene (PS-NHC), and amphiphilic block copolymer (BCP) (PEO--PS-NHC). All three polymer NHCs exhibited enhanced reactivity of gold nanoparticles (AuNPs) during CO electroreduction by suppressing proton reduction.