Harnessing Copper-Metalated Covalent Organic Frameworks: A Biomimetic Approach to High-Efficiency Dye Degradation

Abstract

Schiff-base covalent organic frameworks (COFs), recognized for their designable structures, abundant modification sites, and robust stability, are considered ideal platforms for constructing biomimetic enzymes. This study introduces a strategy for the construction of copper-metalated covalent organic frameworks based on the N–M–O coordination environment of peroxidases’ metal and amino acids. A biomimetic enzyme framework, Cu-COF-TAPT-DHTA, was synthesized by postmetalation with copper. This framework catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with a Michaelis constant K_M of 0.19 mM and a catalytic efficiency k_cat/K_M of 5.26 M^–1·s^–1, demonstrating robust peroxidase activity. Additionally, leveraging the photocatalytic in situ production of hydrogen peroxide by Cu-COF-TAPT-DHTA in conjunction with its peroxidase activity enabled the degradation of methyl orange to reach 98% within 30 min, while malachite green and methylene blue were degraded over 99% within 20 min. The catalytic activity maintained 70% efficiency after seven cycles.