High Current Transport of TiO₂/C-dots@NiO Incorporated Graphene Nanocomposite as Smart Electrode for Diazinon Pesticide Detection

Graphene electrodes incorporated TiO₂/C-dots@NiO (G-TCN) nanocomposites have been successfully synthesized and investigated for their performance in detecting the pesticide diazinon (DZN). The synthesis begins with preparing a C-dots solution hydrothermally using tolaki citrus extract (Citrus sp.) as a precursor. The incorporation was continued hydrothermally between C-dots, Ni (II), and TiO₂ to obtain the TiO₂/C-dots@NiO (TCN) nanocomposites. The results of the morphological study illustrate that the TCN nanocomposite is composed of round particles with a uniform size between 180 and 200 nm. The XRD diffractogram pattern describes the overlapping interactions between the elements that make up the nanocomposites. The electrochemical performance in the Fe(CN)₆³⁻/Fe(CN)₆⁴⁻ solution system illustrates the reversible redox reaction of G-TCN with a value of ∆E_p = 0.08 V. DZN detection showed superior results. Based on the cyclic voltammogram, DZN experienced a reduction at a potential of 0.65 V. The linearity test showed an LOD value of 0.09 μg/mL. In other tests, G-TCN showed good stability and reliability, with an RSD of 11.90% and 7.44%, respectively. The results reported in this work will be a reference for researchers in developing voltammetric sensors for pesticide residue detection.