A Highly Sensitive and Simple Platform for Enzyme-Free Detection of Ethanol Based on a Nano-Porous Glassy Carbon Electrode with Electrodeposited Ni Nanoparticles

In this work, we demonstrated the use of nano-porous glassy carbon electrode (NPGCE) decorated with nickel oxide nanoparticles (NiO_x/NPGCE) as a highly sensitive and straightforward platform for the non-enzymatic electrochemical detection of ethanol. The glassy carbon electrode (GCE) was pretreated by applying constant oxidizing and reducing potentials, respectively, to create a porous carbon nanostructure with an increased surface area. This pretreatment enhanced the loading of NiO_x and its activity towards ethanol electrooxidation. The modified electrode showed a wide ethanol concentration range (0.5–5 mM) with excellent linearity (r = 0.987), a very low detection limit of 75 μM, and a sensitivity of 924.3 µAcm^–2µM^–1 using controlled potential amperometry. The surface coverage of NiO_x/NPGCE was estimated to be 4.86 × 10^–11 mol cm^–2. Furthermore, the specificity of the designed sensor was evaluated, and no cross-reactivity was observed. This developed sensitive platform offers a practical strategy for rapid, simple and cost-effective determination of ethanol in clinical and food samples.