Metalloporphyrin-Based Metal–Organic Framework Nanorods for Peroxidase-Like Catalysis

Metal–organic frameworks (MOFs) and their derivatives are emerging biosensing platforms due to their rational structural optimization. Herein, several metalloporphyrin–Porous Coordinated Network-222 (M-PCN-222) are developed for composition-dependent hydrogen peroxide (H2O2) sensing. A typical colorimetric sensing method (via a 3,3′,5,5′-tetramethylbenzidine-induced allochroic reaction) is employed to investigate the intrinsic peroxidase activity of M-PCN-222 (M = Mn, Fe, Co, and Ni). Fe-PCN-222 affords high sensitivity, good selectivity, robust stability, and a widely applicable concentration range. Theoretical investigations of active sites reveal that such different performances stem from the OH* binding on the M-PCN-222 surface. In addition, the adsorption energy of OH* on Fe-PCN-222 is similar to that of natural horseradish peroxidase. Molecular dynamics simulations are performed on Fe-PCN-222 nanorods to study the catalytic process of H2O2 based on their abundant micropores and mesopores. The obtained results suggest that the porphyrinic Fe-PCN-222 nanorod-based colorimetric sensing of H2O2 has great potential in catalysis, biosensors, and food industries.