Anchoring biomimetic Zn site in metal–organic framework nanozyme to enhance phosphatase-like catalytic activity for discrimination of organophosphorus pesticides

[Display omitted] •A powerful biomimetic approach was proposed to boost the catalytic activity of the phosphatase-mimicking UiO-66-NH2 nanozyme.•By covalently integrating biomimetic Zn sites, the Kcat of the resultant 66-IS-Zn nanozyme was enhanced by up to 130 times.•66-IS-Zn nanozyme exhibited both enhanced self-fluorescence emission and high multi-enzyme activities.•A three-channel sensor array based on 66-IS-Zn nanozyme was proposed for distinguishing organophosphorus pesticides. Herein, a biomimetic approach is developed to improve the phosphatase-like catalytic activity of a metal–organic framework (MOF) nanozyme. Specifically, biomimetic Zn sites, featuring a coordination environment similar to that of natural phosphatase, were covalently anchored into UiO-66-NH2 nanozyme through a step-by-step modification process. Compared with pristine UiO-66-NH2, the resultant 66-IS-Zn exhibited a 130-fold increase in Kcat. Mechanism studies suggest that the anchoring of Zn sites can only enhance the catalytic performance of MOFs that possess intrinsic phosphatase-like activity, and the enhancement of catalytic activity strongly relies on the coordination environment of Zn sites, which involves the co-coordination of N and O with Zn. Besides the excellent phosphatase-like activity, 66-IS-Zn also exhibited enhanced intrinsic fluorescence emission and high phosphodiesterase-like catalytic activity. Consequently, 66-IS-Zn was used as the sensing unit to construct a three-channel sensor array for distinguishing organophosphorus pesticides (OPs). This sensor array can successfully distinguish six OPs and allow the quantification of profenofos and phoxim. Moreover, the binary mixtures of OPs and cherry tomato samples were precisely discriminated without any overlapping, indicating the reliability and practicability of the sensor array.