A novel NO2 sensor based on TiO2 nanotubes array with in-situ Au decoration

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Titanium dioxide (TiO2) is a widely studied material for gas sensing applications.
• Enhancing TiO2 performance, particularly at room temperature, remains a key challenge.
• Noble metal decoration is a promising strategy to improve TiO2-based sensor sensitivity and response.

Purpose of the Study:

• To fabricate gold (Au)-decorated TiO2 nanotubes on a Ti-Au alloy.
• To investigate the sensing performance of the Au-decorated TiO2 nanotubes for nitrogen dioxide (NO2) detection.
• To evaluate the sensor's sensitivity, response time, and stability at room temperature.

Main Methods:

• Electrochemical anodization of Ti-Au alloy to form TiO2 nanotubes.
• Characterization using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM).
• Gas sensing measurements of NO2 at room temperature and 35°C.

Main Results:

• Successfully fabricated Au-decorated TiO2 nanotubes with well-distributed Au nanoparticles.
• The sensor exhibited high sensitivity to low concentrations of NO2 at room temperature (36.11 for 8 ppm NO2).
• Au-decorated TiO2 sensors showed significantly faster response (within 80 s) and more stable signals compared to undecorated TiO2 (>110 s).

Conclusions:

• Au-decorated TiO2 nanotubes fabricated via electrochemical anodization are effective for highly sensitive NO2 detection.
• The sensor demonstrates excellent room-temperature sensing performance with rapid response and enhanced stability.
• This material holds promise for developing advanced gas sensors for environmental monitoring.