Layer-by-layer electrodeposited nanowall-like palladium-reduced graphene oxide film as a highly-sensitive electrochemical non-enzymatic sensor

•Electrodeposition of Palladium nanowall on reduced graphene oxide.•Support of palladium showed an efficient electrocatalytic performance for biosensor.•CV curves of palladium nanowall improved in the presence of reduced graphene oxide.•Agglomeration of reduced graphene oxide has an effect on sensitivity of devices.

Efficient and excellent non-enzymatic electrochemical sensors for H2O2 detection, consisting of reduced graphene oxide (rGO) and palladium (Pd) nanowalls with different rGO loadings, were electrochemically deposited in a layer-by-layer fashion onto indium tin oxide (ITO) glass. The structure and morphology of the as-fabricated non-enzymatic sensor electrodes were confirmed by X-ray diffraction, field-emission electron microscopy, and Raman spectroscopy. The effective combination of Pd nanowalls and rGO nanosheets provides many benefits in electrochemical detection, such as charge carriers with rapid transport and a greater number of sensing sites; thus, the Pd-rGO-modified ITO electrode with 0.5 mg ml−1 rGO displays the best electrochemical sensitivity with regard to H2O2 detection. The responses to H2O2 differ linearly with the concentration (from 100 μM to 12 mM). These devices showed a lowest detection limit of 0.24 μM, excellent stability, and high reproducibility. The enhanced sensitivity of the sensor electrode is due to the synergistic effect between the electrocatalytic activity of the Pd nanowalls and the high conductivity and large surface area of rGO.