Synthesis and Chemoresistive Properties of Single-Layer MXene Ti 2 CT x

As part of the study, we have developed a method for obtaining a single-layer Ti 2 CT x MXene by the interaction of Ti 2 AlC with a mixture of hydrochloric acid and sodium fluoride followed by delamination using a tetramethylammonium hydroxide solution and ultrasonic exposure. The obtained stable aqueous dispersion of Ti 2 CT x has been applied by microplotter printing onto a specialized sensor chip, which has been dried at a temperature of 150°C under reduced pressure. The coating has been studied using modern physicochemical methods of analysis. According to the data of X-ray spectral elemental microanalysis, the ratio n (Ti) : n (F + Cl) = 2 : (0.82–0.85), n (F) : n (Cl) ≈ 6 : 4; aluminum impurity does not exceed 1.5–2.0%. Data have been obtained on the local electrophysical properties of the Ti 2 CT x coating: on the value of the electron work function from the surface of the material, the distribution of charge carriers, and the capacitance gradient of the “probe tip–sample microregion” capacitor. For the first time, at an operating temperature of 30°C, extremely high chemoresistive responses of the Ti 2 CT x receptor layer to the content of 1 and 5% oxygen in nitrogen have been determined, which amounted to 8.6 and >276, respectively.