Synthesis of ZIF-90 based nanozyme with excellent carbonic anhydrase activity

Capturing CO2 using natural carbonic anhydrase (CA) has advantages of environmental friendliness, low energy consumption, renewable and no secondary pollution. However, the high cost, poor stability and low reusability of free CA under harsh conditions limit its industrial applications. Great efforts have been devoted to developing CA mimetic nanozymes to solve these problems. In this work, ZIF-90-based nanoparticles were prepared to mimic the active center of natural CA. The excellent CA-like catalytic activity of ZIF-90 nanoparticles was confirmed by using hydrolysis of p-nitrophenyl acetate (p-NPA) as the model reaction. Moreover, modifying ZIF-90 with monoethanolamine (MEA) could further improve its affinity for CO2, which in turn enhances the CO2 uptake capacity. Moreover, the hydrolysis of CO2 was also investigated through the pH decrease of the reaction solution and the results indicated that CO2 hydration and exchange were remarkably enhanced with the aid of ZIF-90 or ZIF-90 @MEA. This approach is facile and costless, which sheds light on the development of novel catalysts for industrial CO2 capture.