Synthesis, characterization and application of bimetallic XAg/rGO (X = Co, Cu) nanocomposites for electrochemical detection of nitrobenzene

• XAg/rGO (X = Co,Cu) are developed as innovative electrochemical nitrobenzene sensing platforms. • CoAg/rGO’s charge-transfer properties make it ideal for real-time monitoring of nitroaromatic pollutants. • CoAg/rGO exhibited more stable response compared to CuAg/rGO due to weaker NB adsorption. • CoAg/rGO bared robustness with ∼ 5 % variation in repeated measurements/ <10 % signal change over a month. • Minimal impact from SO 4 2− ions and stable NB detection in spiked real water samples are observed. This study presents an innovative electrochemical platform utilizing CoAg/rGO and CuAg/rGO nanocomposites for the detection of nitrobenzene (NB), a hazardous industrial chemical frequently present in waste streams. The prepared materials were analyzed using SEM, TEM, FTIR spectroscopy, and electrochemical techniques, revealing distinct mechanisms in the sensing of NB by the two nanocomposites. Voltammetric measurements demonstrated clear redox peak corresponding to NB reduction in case of both nanocomposites, with the optimal performance in case of CoAg/rGO observed in neutral media. Limit of detection (LOD) of NB of 6.36 μM was determined with CoAg/rGO over 5 – 45 µM linear range, while it was not possible to determine LOD using CuAg/rGO. Moreover, high reporoducibility (<10 % change in signal current), repetability (∼5% variation in signal current) and stability over time (<10 % change in signal current over 1 month) were observed for sensing of NB with CoAg/rGO. Interference by sulphate ions was studied. Finally, CoAg/rGO exhibited excellent sensing capability in spiked real water samples (9 different samples), confirming its high practical application potential. Highly sensitive and stable response of CoAg/rGO in the presence of NB on account of its favourable charge-transfer propreties point it out as a promising candidate for real-time monitoring of nitroaromatic pollutants in water.