Porous carbon-NiO nanocomposites for amperometric detection of hydrazine and hydrogen peroxide

A hydrothermal route is reported for the preparation of a composite consisting of sheet-like glucose-derived carbon and nickel oxide nanoparticles. The nanocomposites were prepared at different annealing temperatures and exploited as electrode materials for amperometric (i-t) determination of hydrazine (N₂H₄) and hydrogen peroxide (H₂O₂) at trace levels. The performances of the sensors were assessed by cyclic voltammetry and amperometry detection using a rotating disk electrode (RDE) technique. The modified electrode annealed at ca. 300 °C was found to exhibit the best electrocatalytic performance in terms of sensitive and selective detection of N₂H₄ and H₂O₂ even in the presence of interfering species. The electrode is inexpensive, robust, easy to prepare in large batches, highly stable, and has a low overpotential. H₂O₂ can be sensed, best at a working voltage of typically 0.13 V vs Ag/AgCl; rotationg speed 1200 rpm) over a wide concentration range (0.01 to 3.9 µM) with a detection limit of 1.5 nM. N₂H₄ can be sensed, best at a working voltage of typically 0.0 V within the concentration range from 0.5 μM to 12 mM with an excellent detection limit of 1.5 µM. Thus, this cost-effective and robust modified electrode, which may be readily prepared in large batch quantity, represents a practical platform for industrial sensing. Graphical abstract Schematic of the hydrothermal method for synthesis of carbon and nickel oxide nanoparticle composites (GCD/NiO-150, GCD/NiO-300, and GCD/NiO-450). The composite was used for the electro-oxidation of hydrazine (N₂H₄) and hydrogen peroxide (H₂O₂) by cyclic voltammetry and amperometry (i-t).