Selective inhibition toward the enzyme-like activity of 3D porous cerium-doped graphene oxide nanoribbons for highly sensitive and enzyme-free colorimetric detection of pesticides

The development of the detection method based on directly inhibiting nanozyme activity holds great promise for on-site monitoring pesticide contamination of foods, while rarely investigated. In this work, a 3D porous cerium-doped graphene oxide nanoribbons (Ce-GONRs) with dual enzyme-like activities (peroxidase and oxidase) were prepared, which could synergistically catalyze the oxidation of TMB. Diafenthiuron and carbaryl were found to selectively inhibit the dual enzyme-like activities of Ce-GONRs, ascribing to π-π stacking and hydrogen bond between pesticides with nanozymes. Based on this mechanism, the enzyme-free colorimetric detection for diafenthiuron and carbaryl were developed. The linear range of diafenthiuron and carbaryl were 10–1500 ng/mL and 2–800 ng/mL, and the detection limits (LOD) of these were 0.57 and 0.23 ng/mL, respectively. The method was successfully applied to detect diafenthiuron and carbaryl in apple and lake water samples. In addition, this work opened up a new way for developing highly sensitive and selective pesticide detection based on the direct inhibition of nanozyme activity through non-metal-sulfur bonding.