Reduced Graphene Oxide/Copper Nanoparticle Composites as Electrochemical Sensor Materials for Nitrate Detection

An efficient electrochemical nitrate (NO3–) sensor consisting of a copper nanoparticle-reduced graphene oxide composite (Cu-rGO) with different rGO loadings was fabricated on indium tin oxide glass (ITO) by simple one-pot electrochemical deposition. The one-pot electrochemical deposition allows for the formation of Cu nanoparticles, reduction of graphene oxide, and decoration of Cu nanoparticles onto the rGO surface simultaneously. The as-electrochemically deposited Cu-rGO-modified ITO electrode was characterized using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The effect of rGO on the electrocatalytic activity of the Cu-rGO-modified ITO electrode toward NO3– reduction was investigated. The Cu-rGO composite with 0.5 mg mL–1 rGO loading shows better sensitivity, a lower detection limit, and a wide linear detection range. Finally, the Cu-rGO-modified ITO electrode with 0.5 mg mL–1 rGO loading was used to measure nitrate in real samples.