Controllable Preparation of 2D V₂O₅ Peroxidase‐Mimetic Nanozyme to Develop Portable Paper‐Based Analytical Device for Intelligent Pesticide Assay

Given severe harmfulness of pesticides, unique characteristics of peroxidase-mimetic nanozymes, and favorable prospects of paper-based analytical devices (PADs), it is highly desirable to construct a nanozyme-based PAD for intelligent analysis of pesticide without enzyme/aptamer/antibody and interference of O2 . Herein, 2D nanosheet-like V2 O5 (2D-VONz) with exclusive peroxidase-mimetic activity is controllably prepared under the optimal reactants concentration and reaction temperature. Experimental characterizations demonstrate that 2D-VONz exhibits high affinity and catalytic rate, and catalytic oxidation is dependent on •OH yielded from the decomposition of H2 O2 catalyzed by 2D-VONz, and the catalytic performance is relevant to π-π stacking force-controlled surface zeta potential of 2D-VONz changed by substrates, giving a comprehensive understand of the inherent mechanism. Interestingly, 2D-VONz activity is inhibited by pesticide glyphosate (Gly), and then is exploited to develop a PAD, on which, Gly declines 2D-VONz activity to prevent it from catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine, contributing to rapid, naked-eye, and portable analysis of pesticide using a smartphone. The current strategy on preparing exclusive peroxidase-mimetic 2D nanozyme, investigating catalytic mechanism, developing nanozyme-based PAD, and achieving direct pesticide sensing will set up new avenues to improve the analytical performance, strengthen the practicability, and broaden the application scope of nanozymes.