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

Two-dimensional (2D) transition metal carbide Ti3C2Tx is the most widely studied MXene and has shown excel-lent metal conductivity, high carrier mobility and rich surface functions due to its unique structure and char-acteristics, which can act as an ideal potential material for electronic devices. Herein, an electrochemical transistor sensor based on ultrathin Ti3C2Tx MXene as a sensing channel was fabricated, which combined with Au nanoparticles (AuNPs)/Ti3C2Tx nanocomposites functionalized gate electrode to realize the electrocatalytic oxidation of nitrite. Utilizing the high electron mobility of the Ti3C2Tx channel and the outstanding electrocat-alytic 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 mu M and 0.5 mu M-5 mM). In addition, the Ti3C2Tx-based device exhibited good selec-tivity, 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.