High-Performance Humidity Sensor Based on Urchin-Like Composite of Ti₃C₂ MXene-Derived TiO₂ Nanowires

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Humidity sensors are crucial for health monitoring, environmental protection, and human-machine interfaces.
• Existing sensors often lack sufficient sensitivity, especially in low relative humidity (RH) environments.
• Titanium carbide (Ti3C2) MXene and titanium dioxide (TiO2) are promising materials for sensor development.

Purpose of the Study:

• To develop a novel humidity sensor with enhanced sensitivity, particularly at low RH levels.
• To investigate the sensing mechanisms of a composite material based on Ti3C2 MXene and TiO2.
• To demonstrate the practical applications of the developed sensor in noncontact detection.

Main Methods:

• Fabrication of a Ti3C2/TiO2 composite using an alkali oxidation method to grow in situ TiO2 nanowires on Ti3C2 MXene.
• Characterization of the composite's morphology and surface area.
• Performance evaluation using complex impedance spectroscopy and humidity sweeps.
• Application testing for noncontact detection of liquids and human fingers.

Main Results:

• The urchin-like Ti3C2/TiO2 composite exhibited an order of magnitude larger surface area than individual components.
• A record high sensitivity of approximately 280 pF/% RH was achieved in the low RH range (7%–33% RH).
• The sensor demonstrated successful noncontact detection of liquids and human fingers.

Conclusions:

• The Ti3C2/TiO2 composite offers a promising platform for developing highly sensitive humidity sensors.
• The unique structure and synergistic effects between Ti3C2 and TiO2 contribute to the enhanced sensing performance.
• The developed sensor has potential applications in various fields requiring precise humidity detection and noncontact sensing.