Investigation of the electrocatalytic activity of metal molybdate MMoO (M = Fe, Ni, and Zn) and the development of the ZnMoO/S-RGO for the electrochemical sensing of pyrimethanil.

The extensive use of pesticides in modern agriculture poses significant environmental and human health threats. This work aims to compare the electrocatalytic activity of structured metal molybdate nanomaterials, MMoO (M = Fe, Ni, and Zn), on the electrochemical oxidation of pyrimethanil (PYR). Among these nanomaterials, ZnMoO manifests superior performance via increasing the PYR oxidation peak currents. This is attributed to the higher crystallinity and optimized surface morphology of ZnMoO, which facilitate efficient charge transfer and promote improved electrochemical behavior. Further, ZnMoO nanomaterials have been incorporated with sulfur-doped reduced graphene oxide (S-RGO) and were employed to construct a simple ultrasensitive sensor for the electrochemical detection of PYR. The prepared ZnMoO/S-RGO/GCE electrode demonstrated excellent performance for PYR detection, with a limit of detection of 4.58 nM and a wide linear range of 0.5-100 μM, a sensitivity of 0.935 μA μM cm, and excellent reproducibility, repeatability, selectivity, and stability. Meanwhile, the real-time performance of the prepared sensor was evaluated by analyzing environmental samples, including river water, and food samples, such as tomatoes and cucumbers. The sensor demonstrated satisfactory recovery rates, ranging from 95.50 % to 101.4 %. Our work results suggest that the prepared sensor is a new strategy for the quantification of PYR in practical applications.