ZIF-4 exhibiting high carbonic anhydrase-mimicking activities

Fixation of greenhouse gas CO₂ using carbonic anhydrase (CA) for waste-to-resource utilization is a green and environmentally friendly treatment strategy. In this work, ZIF-4 was conveniently synthesized using zinc as the metal center and imidazole as the ligand. The CO₂ hydration reaction confirmed that the resulting ZIF-4 is a CA-mimicking nanozyme. The CA-mimicking activities were quantitively evaluated using an esterase activity-based method with p-nitrophenyl acetate (p-NPA) as the substrate. Surprisingly, the CA-mimicking activities of ZIF-4 was significantly higher than those of ZIF-8 and the doped ZIF-8 with 2-methylimidazole as the ligand.