Self‐Assembled Crystalline Peptoid Nanomaterials as Metal‐Free Enzyme Mimics for Enhanced Carbon Dioxide Hydration and Precipitation

Inspired by recently discovered metal‐free carbonic anhydrases (CAs) and other natural enzymes that achieve efficient catalysis without metal cofactors, we herein report a sequence‐defined supramolecular peptoid platform that mimics metal‐free CAs and exhibits hydrolytic activity via a supramolecular assembly‐mediated proton‐transfer mechanism. This rational peptoid design employs a spatially distributed histidine‐inspired functionality within a cyclen‐based macrocyclic scaffold embedded in an amphiphilic peptoid system, enabling self‐assembly into highly crystalline nanosheets and nanotubes. These peptoid assemblies exhibit efficient hydrolysis of 4‐nitrophenyl acetate (4‐NPA) under physiological conditions, with catalytic activity strongly correlated with the spatial organization of imidazole groups and the assembly morphology. Extensive mechanistic studies suggest that the catalysis relies on assembly‐confined proton transfer within the H‐bonding network of peptoid assemblies, thereby promoting general acid‐base catalysis. Additionally, peptoid catalysts enhance CO 2 hydration and precipitation, providing sequence‐defined nanomaterials as a flexible, metal‐free artificial enzyme platform for hydrolytic catalysis and biomimetic mineralization.