MoS2 Nanosheet-Modified NiO Layers on a Conducting Carbon Paper for Glucose Sensing

In this research, we demonstrate a disposable carbon-based paper electrode with engineered surfaces that is capable of detecting glucose in an alkaline medium at concentrations down to 10 μM. The sensitive electrode is fabricated by introducing a hydrothermally synthesized nickel oxide (NiO) layer on a carbon paper electrode, followed by the growth of nanostructured molybdenum disulfide (MoS2) by pulsed laser deposition on the NiO layer. The surface modification was investigated using transmission electron microscopy and micro-Raman spectroscopy. The electrocatalytic activity of the fabricated electrodes was investigated in presence of a low concentration (0.1 mM) of an alkaline solution of sodium hydroxide. The catalytic enhancement of a NiO–MoS2 hybrid electrode is attributed to the edge sites and defects associated with MoS2 nanostructures responsible for creating a highly reactive environment. This system dissociates a water molecule into OH– and H+ species. H+ continues to diffuse on the MoS2 surface, simultaneously modifying it due to its quantum nature. On the addition of glucose molecules into the electrolyte, an oxidation reaction takes place at the surface of the electrode, realizing an enzyme-free glucose sensor. Simulations are carried out via a thin-film-based electrochemical sensor model to better understand the trends in the experimental results. These results indicate a new route to detect glucose at low concentrations and with high sensitivity.