Interfacial proton conduction in MXene/NTO for ultrafast room-temperature NO₂ sensing

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Two-dimensional transition metal carbides and nitrides (MXene) offer potential for gas sensors due to high surface area and conductivity.
• Achieving high sensitivity, stability, and rapid response simultaneously in MXene sensors is challenging.

Purpose of the Study:

• To develop a highly sensitive and selective gas sensor for nitrogen dioxide (NO2).
• To investigate the performance of a novel MXene/sodium titanate (NTO) heterostructure for gas sensing applications.

Main Methods:

• In-situ growth of sodium titanate (NTO) nanoribbons on Ti3C2Tx MXene.
• Fabrication and testing of the MXene/NTO heterostructure gas sensor under ambient conditions.

Main Results:

• The MXene/NTO sensor exhibited an outstanding response of 808.6% to 50 ppm NO2 with an ultrafast response time of ~1s.
• Detection of NO2 at 5 ppb levels with a fully reversible resistance signal and negligible power consumption was achieved.
• The sensor demonstrated high sensitivity, selectivity, and stability for NO2 detection.

Conclusions:

• MXene/NTO heterostructures provide a versatile platform for next-generation room-temperature gas sensing.
• Surface proton conduction in NTO and the interfacial electric field at the MXene/NTO junction enhance charge transfer and NO2 adsorption, leading to exceptional performance.