Efficient detection of nitrite in water based on an Au/NiO/Rh trimetallic composite modified laser-induced graphene electrode prepared by one-step electrodeposition

In this study, we employed a straightforward and rapid one-step electrodeposition method to enhance modify an Au/NiO/Rh composite on laser-induced graphene (LIG) for nitrite (NO2–) detection. We extensively characterized and tested the morphological composition and electrochemical properties of the electrode using scanning electron microscopy and other characterization techniques. To compare the electrochemical active surface areas of the electrode before and after modification, we conducted cyclic voltammetry experiments. Additionally, we confirmed the changes in electron transfer performance and adsorption energy of the modified electrode through by density functional theory calculations. The experimental results demonstrate that the combined modification of LIG with rhodium nanoparticles (RhNPs) and gold nanoparticles (AuNPs) improves electron transport ability at the electrode interface and enhances the electrode's electrocatalytic performance. The incorporation of nickel oxide (NiO) also provides a larger reaction area and more active sites for NO2– detection. The synergistic effects of these three modified components significantly enhance NO2– detection at the electrode, surpassing the performance of the bimetallic modified electrode. Under optimized experimental conditions, the sensor exhibits a linear range of 1 μmol/L to 1 mmol/L and a detection limit of 0.3 μmol/L. Furthermore, the sensor demonstrates excellent anti-interference and repeatability properties. We successfully applied the sensor for determination of NO2– in tap water, yielding satisfactory results. This research presents a promising strategy for the portable, sensitive, and in-situ detection of NO2– in water environments using metal-based electrochemical sensors.