Zirconium and vanadium bimetallic organic framework nanozyme for bioenzymes-free colorimetric and photothermal dual-mode direct detection of organophosphorus pesticides

Abstract

Presently, the vast majority of colorimetric methods for the detection of organophosphorus pesticides (OPs) generally require the presence of bioenzymes coupled with just single-signal mode. Herein, by using VCl3 and ZrCl4 as the metal precursors as well as 2-aminoterephthalic acid as the coordination ligand, we firstly designed and prepared successfully a novel bimetallic Zr/V-based UiO-66-NH2 organic framework nanozyme which could offer prominent peroxidase (POD)-like activity to catalyze the oxidation of 3,3,5,5-tetramethylbenzidine efficiently. The results revealed this oxidation process could induce color change of the nanozyme catalytical system and interestingly the system temperature would be increased after a near infrared laser. Additionally, the as-prepared bimetallic nanozyme could bond with the OPs structure specifically and its POD-like activity would be inhibited in the presence of OPs. Based on these interesting phenomenons, a bioenzymes-free colorimetric-photothermal dual-mode direct sensing strategy of OPs was then proposed for the first time in this work. Upon optimizing various conditions, the as-proposed sensing strategy achieved simple, sensitive and direct dual-mode detection for OPs, which may offer a new tool for the OPs analysis in the real application.