ZIF-67 derived CuCo2O4 based Reduced Graphene Oxide-sensitized H-C3N4 modified FTO based sensor for Electrochemical sensing of Glyphosate in real samples

Abstract

Glyphosate is considered as one of the most common, toxic and non-electroactive organophosphorus herbicide used widely in agriculture and food industries to satisfy the demand of huge population because of its ability to control weeds effectively. However, the unlimited usage of this shows detrimental impacts on animals, environment, and potential indirect effects on human health significantly. Therefore, a sensitive detection of glyphosate in different real samples is highly demanded for the protection of living beings. Towards this context, an easy, rapid, cost-effective non-enzymatic senor involving ZIF 67-derived CuCo2O4 decorated on rGO/protonated g-C3N4 modified different electrodes like GCE, ITO, FTO are used for comparative analysis as a sensitive and selective photo-electrochemical sensor for the detection of glyphosate. The designed nanocomposite has been synthesized via simple hydrothermal synthetic route followed by calcination. After then, the nanocomposite has been characterized thoroughly by various sophisticated analytical techniques such as FTIR, XRD, Raman, FESEM, TEM with EDS mapping, and XPS to investigate the successful synthesis of desired nanocomposite. The large specific area and hierarchical pores of MOF-derived CuCo2O4 significantly increase the effective area of electrode and adsorption capacity followed by the addition on FTO as electrode amplifies the electrode response site as well as the detection limit. Later on, the electrochemical sensing performance of the synthesized nanocomposite was investigated by using Cyclic voltammetry, Square wave voltammetry and Differential Pulse Voltammetry. Then the optimized sensing conditions were obtained by varying different sensing parameters such as material loading, pH, temperature and incubation time. The design nanomaterial has able to detect a wide range of pesticide concentrations (1μM-1nM) with a lower limit of detection (LOD = 23.69 pM) (S/N = 3) under optimized sensor conditions, which was further verified by Nyquist plot. In addition, the reusability and stability of the sensor were also studied for 30 days. Finally, the material has successfully applied for real sample analysis in different fruits and vegetables. The enhanced sensitivity of the synthesized nanomaterial is due to the synergistic combination of rGO, protonated g-C3N4 and CuCo2O4 along with controllable pore structures, large BET surface area, good adsorption capacity, and more no of exposing redox-active sites, which leads to rapid transmission of electrons during the sensing application in the nanocomposite. This study bring new opportunities for the detection of non-electroactive pesticides not only in wide detection range and ultra-low detection limits, but also displays low detection limit, good reproducibility and favorable selectivity