Metal covalent organic frameworks-based laccase-like nanozyme for oxidative degradation and identification of phenolic pollutants

Phenolic compounds are a kind of persistent organic pollutants (POPs), which are always a threat to human and environment due to their strong toxicity and low biodegradability. Therefore, developing a reliable method to simultaneously detect phenolic pollutants is of great importance to environmental safety and human health. Herein, we combined the advantages of metal organic frameworks (MOFs) and covalent organic frameworks (COFs) to prepare two cyclic trinuclear unit-based metal covalent organic framework (MCOFs, denoted as Cu3- TDH COF and Cu3-BDU COF) with large specific surface area, good stability and excellent laccase-like activity. Their oxidative degradation ability toward phenolic pollutants was verified, and a dual-channel nanozyme sensor array based on Cu3-TDH COF and Cu3-BDU COF was constructed for the identification of six phenolic pollutants. Notably, the sensor array can accurately distinguish between different concentrations of phenolic pollutants and different types of phenolic pollutants at the same concentration, even at levels as low as 1 mu M. Moreover, three real water samples (rainwater, tap water and wastewater) and 18 unknown samples were also distinguished and differentiated by the sensor array. This study opens up a potential avenue for the design of MCOFs-based nanozyme sensor arrays to simultaneously realize identification and detection of multiple phenolic pollutants.