Hollow porphyrin-based porous organic polymer with dual enzyme-like activities for ultra-fast colorimetric detection of Cr (VI) in wastewater

Abstract A hollow porphyrin-based porous organic polymer (H-Fe-POP) was prepared for rapid and sensitive colorimetric determination of Cr(VI), which exhibited excellent dual enzyme-like activities, including oxidase-like and peroxidase-like activities. Due to the specific binding of 8-hydroxyquinoline (8-HQ) to Cr(VI), 3,3′,5,5′-tetramethylbenzidine (TMB) was liberated, and TMB was oxidized to blue ox-TMB catalyzed by H-Fe-POP. Based on the excellent oxidase-like activity of H-Fe-POP, an ultra-fast colorimetric platform for the detection of Cr(VI) was constructed, allowing the quantification of Cr(VI) in the range 2–130 μM within 30 s with a detection limit of 0.23 μM. Importantly, the sensor can accurately determine Cr(VI) in industrial wastewater, indicating its high potential for environmental monitoring. Graphical Abstract