Bifunctional ZrO₂@ZIF-90 nanozyme with high phosphohydrolase activity for sensitive electrochemical detection of methyl parathion

In this work, a novel bifunctional zirconium dioxide@zeolitic imidazolate framework-90 (ZrO₂@ZIF-90) nanozyme was successfully developed for the catalytic degradation and electrochemical detection of methyl parathion (MP). The ZrO₂@ZIF-90 nanozyme with phosphatase hydrolysis activity can convert MP into p-nitrophenol (p-NP). The addition of ZrO₂ riched in Lewis acid Zr(Ⅳ) sites significantly enhanced the phosphatase hydrolysis activity of ZIF-90. ZrO₂@ZIF-90 also displayed satisfactory electrocatalytic performance on account of the high surface area, high porosity and powerful enrichment ability of the ZIF-90 and the excellent ion transfer capacity of ZrO₂. A ZrO₂@ZIF-90 nanozyme modified glassy carbon electrode (ZrO₂@ZIF-90/GCE) was then fabricated to analyze p-NP formed through MP degradation. Under the optimized conditions, the developed sensor displayed satisfactory analytical performance with a low limit of detection of 0.53 μmol/L and two wide linear ranges (3-10 and 10-200 μmol/L). ZrO₂@ZIF-90 nanozyme accomplished to the degradation and electrochemical detection of MP in river water and spiked fruits. This study identifies a promising new strategy for the design of bifunctional nanozymes for the detection of environmental hazards.