Fabrication of polyphenol-etched amino acid-modified ZIF-8 and their carbonic anhydrase-like catalytic activity

Carbonic anhydrase mimics have recently emerged as promising alternative catalysts for industrial CO2 capture and utilization. Up to now, many strategies have been developed to design and prepare nanostructures with excellent carbonic anhydrase-like catalytic activity. Herein, two kinds of polyphenol molecules (tannic acid (TA) and gallic acid (GA)) were used to etch amino acid (valine (Val) and leucine (Leu)) modified ZIF-8 (AA-ZIF-8) for fabricating carbonic anhydrase mimics. The TA-treated AA-ZIF-8 (Val-ZIF-8/TA and Leu-ZIF-8/TA) possess hollow nanostructure while the GA-treated AA-ZIF-8 (Val-ZIF-8/GA and Leu-ZIF-8/GA) are decomposed into smaller nanoparticles. Zn-polyphenol coordination interaction and protons released by polyphenols are considered to be the driving force for the etching of AA-ZIF-8. Using hydrolysis of p-nitrophenyl acetate (p-NPA) as the model reaction, the carbonic anhydrase-like activity of AA-ZIF-8/polyphenol nanoparticles were evaluated and the results indicated their excellent catalytic activity. Moreover, after using AA-ZIF-8/polyphenol as catalysts, the CO2 hydration efficiency could also be enhanced. This work provides a new approach for developing carbonic anhydrase mimics, which could help for designing of materials for industrial CO2 capture.