A gold nanoparticles/nitrogen doped graphene quantum dots/reduced graphene oxide ternary nanocomplex for electrocatalytic sensing of hydrazine in environmental water samples

A novel electrochemical sensor for hydrazine (N₂H₄) detection was reported based on a glassy carbon electrode (GCE) modified with a ternary nanocomposite composed of gold nanoparticles (AuNPs), nitrogen-doped graphene quantum dots (N-GQDs), and reduced graphene oxide (rGO). The fabricated AuNPs/N-GQDs@rGO/GCE was characterized by several techniques and displayed excellent electrocatalytic activity towards N₂H₄ oxidation. Optimization of experimental parameters, including the volume ratio of N-GQDs and rGO, electrodeposition time of AuNPs, pH of detection solution, and enrichment time, was performed to achieve optimal performance. A wide linear detection range (10 nM to 20 μM), a low limit of detection of 5 nM (S/N = 3), and high sensitivity (31 μA μM⁻¹) were obtained for N₂H₄ determination. Moreover, the fabricated AuNPs/N-GQDs@rGO/GCE shows superior selectivity, reproducibility (relative standard deviation (RSD) = 5.5%), and stability (RSD = 6.3% over 10 days), with minimal interference from common coexisting species. Application of the prepared sensor to real environmental water samples demonstrated good recoveries between 98.0% and 104.0%, confirming its reliability for environmental monitoring and offering a promising tool for environmental analysis.