Integrated Modulation of Fe, Co-MOF Nanozymes for Expressing Peroxidase-like Activity: Enhanced Affinity for H₂O₂ and Analysis of Isoniazid

The limited affinity of horseradish peroxidase (HRP) for H2O2 makes it unsuitable for identifying situations containing trace amounts of H2O2. Herein, a set of regulation schemes for Fe, Co-MOF was proposed to develop a substitute for HRP. Regarding H2O2 adsorption, solvent engineering allowed the MIL framework to expose the (101) crystal plane with the highest density of Lewis acid sites, and the unsaturated center of the ligand generated by the Co sites on the 1D metal–oxygen chain facilitates the adsorption of H2O2 in sub-nanochannels. Regarding H2O2 reduction, ligand amination engineering created electron donor regions. Hydrogenation engineering increased the number of Fe2+ as catalytic centers, and the synergy between in situ modified tiny AuNPs and them reduced the activation energy of the peroxidase-like reaction. Ultimately, the affinity of Fe, Co-MOF for H2O2 was increased by 70 times compared with HRP. As a proof-of-concept, it was used to detect isoniazid, a typical antituberculosis drug, in human urine samples.