Ultrathin Ti3C2Tx MXene-based electrochemical transistor for highly sensitive determination of nitrite

Two-dimensional (2D) transition metal carbide Ti 3 C 2 T x is the most widely studied MXene and has shown excellent metal conductivity, high carrier mobility and rich surface functions due to its unique structure and characteristics, which can act as an ideal potential material for electronic devices. Herein, an electrochemical transistor sensor based on ultrathin Ti 3 C 2 T x MXene as a sensing channel was fabricated, which combined with Au nanoparticles (AuNPs)/Ti 3 C 2 T x nanocomposites functionalized gate electrode to realize the electrocatalytic oxidation of nitrite. Utilizing the high electron mobility of the Ti 3 C 2 T x channel and the outstanding electrocatalytic activity of the gate material, the transistor sensor achieved ultrasensitive detection of nitrite, including the urtralow detection limit down to 0.01 nM, which is lower than those of other available methods and wide linear range (0.01 nM-0.5 μM and 0.5 μM-5 mM). In addition, the Ti 3 C 2 T x -based device exhibited good selectivity, long-term stability and practicability, realizing the accurate detection of nitrite in natural lake water, which provided a new way for the highly sensitive monitoring of nitrite in environmental and food safety.