Highly selective NH₃ gas sensor based on Co(OH)₂/Ti₃C₂T nanocomposites operating at room temperature

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Ammonia (NH3) is a critical air pollutant and a key biomarker for kidney disease.
• Developing highly sensitive, selective, and low-operating-temperature ammonia gas sensors is vital for public health and environmental monitoring.
• Existing sensor technologies often face limitations in performance and operational conditions.

Purpose of the Study:

• To create a chemoresistive gas sensor utilizing a novel Co(OH)2/Ti3C2Tx hybrid material.
• To evaluate the gas sensing properties of the fabricated sensor for ammonia detection.
• To assess the potential of this hybrid material for health protection and IoT applications.

Main Methods:

• Synthesis of Co(OH)2/Ti3C2Tx hybrid material using in situ electrostatic self-assembly.
• Characterization of material structure, surface topography, and elemental composition via XRD, XPS, TEM, and BET.
• Fabrication of chemoresistive sensors and testing of ammonia gas sensing performance under various conditions.

Main Results:

• The Co(OH)2/Ti3C2Tx hybrid sensor (C/M-2) achieved a gas response of 14.7% at 100 ppm NH3, which is three times higher than pure Ti3C2Tx.
• The sensor demonstrated high sensitivity at low ammonia concentrations (<5 ppm).
• Excellent repeatability, fast response (29 s) and recovery (49 s) times, and long-term stability were observed.

Conclusions:

• The Co(OH)2/Ti3C2Tx hybrid material significantly enhances ammonia gas sensing performance compared to pure Ti3C2Tx.
• The developed sensor exhibits promising characteristics for effective ammonia detection in health monitoring and IoT systems.
• The in situ electrostatic self-assembly method is effective for creating advanced gas sensing materials.