In Situ Growth of a TiO2 Nanosheet on Amorphous Carbonaceous Layer for Sensing NH3 at Room Temperature.

The development and manufacture of room-temperature NH₃ respiratory gas sensors are particularly important in the medical field. However, current NH₃ sensors either lack sensitivity or have slow response and recovery. Herein, in situ growth of TiO₂ nanosheet on the layered amorphous C derived from oxidation of Ti₃C₂T_x by a hydrothermal method is proposed. The resultant gas sensing performance showed that the TiO₂-C-2 (hydrothermal reactor for 12 h) specimen exhibited a high gas response value (10.3) and short response and recovery times (69 and 82 s, respectively) to 100 ppm of NH₃ at room temperature. In the UV light environment, gas sensitivity is further improved (from 10.3 to 14.2 for 100 ppm of NH₃ response value) and response and recovery times are reduced from 69 and 82 s to 50 and 60 s, respectively. Finally, selective adsorption of NH₃ was characterized by density functional theory (DFT). This study confirms that the in situ growth of a TiO₂ nanosheet on the layered amorphous C for gas-sensitive detection is expected to be a strategy. [ABSTRACT FROM AUTHOR]