Preparation and characterization of gold nanoparticles decorated on graphene oxide@polydopamine composite: Application for sensitive and low potential detection of catechol

We report a highly sensitive and selective electrochemical catechol (CT) sensor based on gold nanoparticles (AuNPs) decorated on graphene oxide@polydopamine (GO@PDA) composite modified glassy carbon electrode. The as-prepared composite materials were characterized by scanning electron microscopy, energy-dispersive X-ray, Raman and Fourier transform infrared spectroscopy. The GO@PDA-AuNPs composite modified electrode shows a well-defined redox couple with a better peak to peak separation for CT than that of GO-AuNPs, GO@PDA and GO modified electrodes. Furthermore, GO@PDA-AuNPs composite modified electrode shows an enhanced oxidation peak current response and low oxidation potential for the detection of CT than that of other modified electrodes. Under optimum conditions, the response current of CT at GO@PDA-AuNPs composite modified electrode was linear over the concentration ranging from 0.3 to 67.55 μM with the detection limit of 0.015 μM. The sensitivity of the sensor was estimated as 4.66 ± 0.15 μAμM^-1 cm^-2. The GO@PDA-AuNPs composite modified electrode shows its superior selectivity towards CT in the presence of 100-fold additions of potentially active compounds including hydroquinone. In addition, the fabricated composite electrode is also applied for the determination of CT in the tap water samples.