Preparation of defective UiO-67 for CA immobilization to improve the ability of CO2 capture and conversion

Carbonic anhydrase (CA) has been suggested as a biocatalyst for carbon dioxide capture since it could effectively catalyze the hydration of carbon dioxide. Metal-organic frameworks (MOFs) have attracted significant attention in the development of immobilized enzyme carriers due to their pore tunability and excellent stability. In this study, UiO-67 materials with varying defect degrees (DUiO-67) were prepared using the organic linker missing method to enhance the catalytic performance. The results indicated that both the defect degree and the pore size of DUiO-67 materials decreased with an increase in acetic acid equivalent. After CA immobilization, all DUiO-67 materials exhibited excellent thermal, pH and recycling stability. CA@DUiO-67-25 showed higher enzyme catalytic activity and conversion ability than the other materials. After 10 cycles, CA@DUiO-67-25 retained 57 % of its initial conversion capacity. The construction of defective MOFs provides a promising new strategy for CA immobilization to achieve the catalytic conversion of CO2.