Electrochemical preparation of biomolecule stabilized copper nanoparticles decorated reduced graphene oxide for the sensitive and selective determination of hydrogen peroxide

Copper nanoparticles (CuNPs) with an average diameter of 70 ± 20 nm were deposited on glassy carbon electrode (GCE) through a simple, facile and template free electrochemical potentiostatic method. The sizes of CuNPs were readily controlled using a biomolecule, histidine that acts as stabilizing agent. The effect of histidine concentration on the formation of CuNPs was studied in the fixed concentration of copper ions. To increase their surface area and the catalytic activity, histidine stabilized CuNPs were deposited on the surface of reduced graphene oxide (RGO) to form RGO/histidine-CuNPs nanocomposite. The as-prepared nanocomposite was confirmed by various techniques. RGO/histidine-CuNPs/GCE was used to develop a highly sensitive and selective sensor for the detection of hydrogen peroxide (H2O2). The sensor showed a good linear response to H2O2 in the range of 1 μM to 5 mM with a low detection limit (LOD) of 75 nM. The fabricated modified electrode detected H2O2 selectively even in the presence of other biomolecules such as dopamine, ascorbic acid, uric acid, acetaminophen, glucose and L-cysteine. Practicality of the sensor was demonstrated in human urine samples. The important features of this nanocomposite are simple, low cost, ecofriendly and easy fabrication of sensor for sensitive and selective determination of H2O2.