Layer-by-layer (LbL) deposition is a versatile method to prepare thin film coatings with alternating layers of oppositely charged materials. The layers may be installed using different processes such as drop casting, dip coating, spin coating, spray coating, the choice of which have a significant impact in accurate reproducibility and the electrochemical properties of the resulting hybrid electrode.
The last few years a great intertest has being taken in the development and functionalization of 2D materials in electronic applications mainly due to their high conductivity. MXenes possess a unique combination of physicochemical characteristics that render them particularly attractive for sensing applications. Their electrical conductivity facilitates rapid electron transfer, which is essential for effective signal generation in electrochemical sensors. At the same time, their large surface area coupled with the presence of diverse surface terminations such as -OH, -O, -F, and -Cl provides abundant active sites and allows their functionalization with other materials such as Graphene Oxide (GO), leading to the formation of hybrids with improved and synergistic functional properties.
In this study, LbL deposition of Ti₃C₂Tₓ MXenes and GO was employed for the modification of GCEs using two different assembly approaches, namely dip coating and drop casting. The influence of the deposition method on film formation, structure and interfacial properties of the MXene-GO hybrid electrodes were assessed using a combination of structural, surface, and electrochemical techniques, including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Water Contact Angle measurements (WCA), Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and cycling stability tests. Results showed that the LbL-assembled hybrid coatings significantly enhanced the electrochemical performance of the modified electrodes compared to bare GCEs, while clear differences between dip-coated and drop-cast electrodes were observed in terms of charge transfer resistance, surface wettability, and electrochemical stability. Based on the above results, the developed hybrid electrodes could be used as electrochemical sensing platforms for glucose and lactate detection, exploiting the synergistic properties of MXenes and GO.
