Fabrication of ionic liquid stabilized MXene interface for electrochemical dopamine detection

Development of MXene (Ti₃C₂Cl₂)-based sensing platforms by exploiting their inherent active electrochemistry is highly challenging due to their characteristic poor stability in air and water. Herein, we report a cost-effective methodology to deposit MXene on a conductive graphitic pencil electrode (GPE). MXenes can provide active surface area due to their clever morphology of accordion-like sheets; however, the disposition to stack together limits their potential applications. A task-specific ionic liquid (1-methyl imidazolium acetate) is utilized as a multiplex host material to engineer MXene interface via π-π interactions as well as to act as a selective binding site for biomolecules. The resulting IL-MXene/GPE interface proved to be a highly stable interface owing to good interactions between MXene and IL that inhibited electrode leaching and boosted electron transfer at the electrode–electrolyte interface. It resulted in robust dopamine (DA) oxidation with amplified faradaic response and enhanced sensitivity (9.61 µA µM⁻¹ cm⁻²) for DA detection. This fabricated sensor demonstrated large linear range (10 µM − 2000 µM), low detection limit (702 nM), high reproducibility, and good selectivity. We anticipate that such platform will pave the way for the development of stable and economically viable MXene-based sensors without sacrificing their inherent properties.

Graphical abstract

Scheme 1 Schematic illustration of the IL-MXene/GPE fabrication and oxidative process towards non-enzymatic dopamine sensor