Ligand-Defect Modulation of UiO-66(Ce) Unlocks Oxygen-Vacancy-Driven Glyphosate Hydrolysis and Sensitive Detection

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Chemistry

Background:

• Glyphosate, a widely used organophosphorus herbicide, poses significant environmental and health risks.
• Developing efficient methods for glyphosate detection and degradation is crucial for environmental protection and food safety.

Purpose of the Study:

• To develop a biomimetic dual-function nanozyme for efficient glyphosate hydrolysis and sensitive detection.
• To engineer a cerium-based metal-organic framework (UiO-66(Ce)-3) with oxygen vacancies for enhanced catalytic activity.

Main Methods:

• Synthesis of a cerium-based metal-organic framework (UiO-66(Ce)-3) with engineered oxygen vacancies.
• Investigation of acetic acid-triggered "missing-linker" defects to generate oxygen vacancies and expose Ce3+/Ce4+ redox sites.
• Evaluation of the nanozyme's organophosphorus hydrolase-like activity under alkaline conditions and oxidase-like activity at pH 4.0.

Main Results:

• UiO-66(Ce)-3 exhibited excellent organophosphorus hydrolase-like activity (kcat = 57.77 s-1, SA = 0.70 U·mg-1, kcat/Km = 152.04 × 103 M-1 s-1).
• The nanozyme effectively mitigated glyphosate-induced toxicity in plants, achieving a 95% survival rate.
• High-sensitivity detection of glyphosate was achieved via point-of-care testing with a limit of detection (LOD) of 11.66 ng·mL-1 and good recovery rates (93.51%-110.19%) in complex matrices.

Conclusions:

• The developed pH-switchable nanozyme demonstrates efficient glyphosate degradation and sensitive detection capabilities.
• Engineered oxygen vacancies in UiO-66(Ce)-3 are key to its dual enzyme-like activities.
• This work presents a novel approach for the detection and remediation of organophosphorus compounds.